The weather reports over the last few days hadn’t been looking great, so both the model and I knew well in advance that there was a chance that the game could be called on account of rain.  That’s pretty much what happened.  Even as late as 9:30 the morning of the shoot, the weather reports said the heavens would open up at around 11am and not stop pouring until about 5 or 6pm.  So, we called it off to reschedule it for another day.  This turned out to be a mistake, as you’ll see later.

As I’d already arranged an assistant for the day, the two of us decided to still go out anyway and just do some location scouting.  Even if it’s raining, shooting with my iPhone isn’t a big deal (I use my iPhone when location scouting so I get GPS tagged photos that I can map out when I get back home).

We decided to head up near Coniston Water, as I’d seen a couple of spots there last weekend that I wanted to explore further.  On the way up we drove through some rain, literally – we could see it raining ahead of us, we hit it, and 30 seconds later we could see it still falling in the rear view mirror.

Once we arrived near Coniston, we accidentally took a wrong turn, which turned out to be a good one, as I noticed a little stream off to the side of the road shortly after we’d realised our mistake (this is why I scout with the iPhone, it’s easy to get lost on some of these country roads).  Not really expecting it to turn out to be much, we parked up and checked it out anyway.  It went on for about half a mile, containing some of the clearest water I’ve seen around here, with little waterfalls varying from about 18″ to 6ft every 50ft or so along the half mile-ish stretch (and I do like my waterfalls).

The sky was still somewhat great, but it was bright enough to get some decent shots showing the general area – all shot on the iPhone 4s.

10 minutes later we were off.  Couple of little spots of wet hitting the face hinting at a downpour.  We waited, nope, nothing.  The rain continued to hold off.
Back in the car we go, turn around and head back in our original direction, and we make it down to the lake.  Despite the distinct lack of rain, it was still rather dull and boring, and there were quite a few die-hards getting ready to send their various boats and kayaks into the water, so I grabbed one shot (GPS tagging!), with the intention of returning on a better day, and left.

Upon heading back to the car park and preparing to leave, we confronted with the image you see above right.  Decision made (we do that), that was going to be our next spot to check out (we saw what we thought was a stream of water flowing down, and I wanted to know where it was coming from – it didn’t look THAT high).

After driving up to it, and around it, trying to find a way to get close-ish, we turned the corner, saw another mountain, and decided to head for that one instead.  And boy, am I glad we did!

After finding a spot to park, we had a little wander around, found another stream, took a few shots of that, then got to the base of a mountain – which had a very handy set of stone steps leading up the initial tricky climb, and leading to a path, of sorts.

Turns out this mountain was an old slate quarry, no longer in use.  Was pretty cool to make our way inside there, with walls at least 50ft high, we were fairly sheltered from the wind, and barely felt a mild breeze.

I’ve saved this until the end, but on our way in, we ran across a path, which led to something I’ve been seeking for a long time.  A cave!  Well, sort of, it only goes back about 20ft into the rock, but the light falls off so rapidly, it looks like it could go on forever.  Absolutely perfect for an idea that’s been floating around in my head for a couple of years.

After this, it was time to head home, just as the sun was really starting to shine.

The moral of the story?  Well, there’s two.

1) If you have to cancel a shoot, don’t waste the day.  Get out there and do something useful and productive, even if it’s just driving around and scouting out new areas to determine if there’s any locations worth shooting at.  You may be surprised by what you find!

2) Try not to cancel unless you absolutely, really, positively have to.  The weather guys in this country seem to get it wrong more often than not these days.  What was supposed to be a thundery, rainy, storm-packed day turned out to be rather lovely and could’ve made for some fantastic photographs.

Until next time, happy shooting!

On the flash workshops I teach, this is also the one question that almost everybody wants the answer to.  People typically come to my flash workshops because they have little or no experience with flash, are confused by the vast amount of information and options out there , and just want it translated into plain English with practical examples that they can try themselves.  So, their question is perfectly reasonable, and they are often quite surprised by how little it can cost to get them up and running with a basic one light system.

The biggest problem I’ve found in all of this is weighing up budget vs. versatility.  Each component in a basic flash setup is going to depend on what each individual photographer needs and wants to learn & shoot.  Everybody also has a different idea of “on a budget”.

So, I will present my preferred option first, for each component in the setup, and below each, some boxes with suitable alternatives. It’s not that there’s anything wrong with the alternatives, but as I mentioned above, budget vs. versatility. Sometimes you can sacrifice certain features in order to save a little money, and sometimes you absolutely have to have certain features and it’s worth it to spend a little more.

All of these items should be available from many different sellers on eBay, both in the UK and direct from Hong Kong or China (with free shipping they often work out a little cheaper, but you could be waiting up to 12 weeks for them to actually arrive).  Some are also available from more traditional photographic retailers.

First up, the flash unit itself, and I’ll probably go a bit more in-depth on this one than I will with the rest of the items.

Flash : Yongnuo YN560 (typical price £40-50)

Given the price, this is probably one of the best speedlights on the market at the moment.  It’s as powerful as a Nikon SB-800 or Canon 580EX2, but without all the brand specific features (TTL, wireless remote control, etc).  It’s fully manual, meaning you’ll physically have to walk over to the flash in order to adjust the power output, but that’s only what we’ve had to do for years with studio strobes anyway.  The build quality is excellent, although early versions of this flash seemed a little easy to kill, and it was updated in 2011 to offer a metal foot and other modifications to increase physical strength and durability.  I still wouldn’t like to test if it’ll bounce off concrete though.

Power Output

As mentioned above, this flash has about the same output as a Nikon SB-800, while the body of the flash itself is loosely modelled on the Canon 580EX2.  Added to this revision of the flash is a zoomable head, which goes from 24-105mm.  This allows you to broaden or narrow the beam of light emitted from the flash in order to focus it where you need it.  It also has a built in flip out wide angle adapter in order to spread that beam out as wide as 18mm.

Remember, though, the wider you spread the beam, the lower the effective power becomes as it’s spread across more area.  Inversely, the narrower you spread the beam, the more power and the more light you can focus to a smaller area.  The zoom setting of your flash doesn’t need to be the same as the focal length of your lens if the flash is not sitting on the hotshoe of the camera.

Triggering Methods

The YN560 offers several ways to be able to trigger it.  It has two optical slave modes; One being the typical “see a flash go off and fire” mode we’ve had for years, the other being a pre-flash ignoring mode (handy if you want to mix it in with TTL or optical AWL type setups).

It also features a PC Sync socket, for traditional cabled firing (also very handy when used in certain light modifiers where space can be at a premium & positioning is important, or when using custom triggers for high speed photography).

Finally it can be triggered via a hotshoe – either sat right on the top of your camera, or via radio trigger, such as the RF-602 or RF-603 (which can also connect to the PC Sync socket with the appropriate cable).

Batteries & Recycle Time

As with most hotshoe flashes, the YN560 is powered by 4 AA batteries, but it also features a socket into which you can plug an external battery pack for even faster recycle time and longer usage between battery replacement.  When using alkaline batteries, the YN-560 has a full power recycle time of around 4 seconds.  Using NiMH batteries, that drops down to under 2 seconds (which is extremely impressive for a flash with this kind of power).

That said, if you’re gunning it like a lunatic, it may have a tendency to go into “thermal protection mode” and make you wait for it to cool down a little bit.  With the battery pack, this recycle time likely drops down to around a second or less, but given the potential for it to overheat, I wouldn’t take advantage of that too often.

Handy but not essential features

The YN-560 also offers pretty rapid fire shooting abilities at lower power levels.  Their website claims you can shoot continually at 8fps at 1/8th power or lower, but for how long it can keep this up I don’t know.

Verdict

I started this section off by saying that this is probably one of the best speedlight on the market given what it costs, and I stand by that.  The Nikon SB-900 costs about 8 times as much as the YN560, and while it offers fantastic features and time saving abilities, the YN560 can stand up to most jobs just as well.

Overall, this is the one I would recommend the most, and the one I would be looking to purchase myself, if I did not already own several SB-900s.

Alternatives

Light Stand : Konig 2m Light Stand (typical price £10-15)

I own 4 of these light stands, and they’re not bad at all.  They’re fairly light (no pun intended), which means they can have a tendency to fall over in a breeze with an umbrella attached if you’re not careful, so make sure you have sandbags with you or somebody to hold on to the stand to make sure it doesn’t blow away.  At this price bracket though, there aren’t really any other alternatives that offer anything extra over the Konig stands.

They support a weight of up to 2.5KG, which is more than enough for a speedlight, bracket and most light modifiers.  These go with me in my lighting bag everywhere, and are what I probably use the most often when out on location.

Alternatives

Umbrella Bracket : Interfit Strobies Umbrella Holder (typical price around £15)

There are a number of different options out there for umbrella brackets, and there are certainly cheaper alternatives to this (two are mentioned below), but this is as close as I can find to the ones I use.  The ones I have, I acquired in an auction and have not seen them online for sale anywhere since, but these come closest (I believe Manfrotto/Bogen make a similar one too, although it’s slightly more expensive).

Like the light stands, there’s not much to umbrella brackets, they all do pretty much the same job, but the long handle on the design of this one makes adjustments quick and easy.  It has a hole in the bottom to attach it to your light stand, a shoe on the top into which you can place your flash and a hole through which you put the shaft of your umbrella, with a little thumbscrew to hold it in place (don’t tighten those too much or they will crush the shaft of your umbrella).

Whichever one you go for, make sure it has an adjustable stroboframe style shoe, that you can screw open and closed.  Trust me, it’ll make life a lot easier when you’re setting up and packing down, or if you need to make quick changes in your lighting setup.

Alternatives

Radio Triggers : RF-602 (around £25-30 for a Tx/Rx set)
There are many different options out there for radio triggers these days.  Some are ridiculously cheap, in price, build quality and reliability, and some are ridiculously expensive (PocketWizards).  The good news, for us, is that you can get inexpensive triggers that are rock solid, have great build quality and are completely reliable. Here enters the RF-602 trigger set.

The basic RF-602 kit is a transmitter (Tx) and receiver (Rx).  The Tx goes onto the camera’s hotshoe, and the flash sits in the shoe on the Rx. But, you don’t have to use it as a flash trigger. The RF-602 kit also has cables available that allow you to plug it in to many Nikon and Canon DSLRs and use it as a remote camera trigger too, or for using them with studio strobes. In the image above, you can see two of these cables. One is the 3.5mm flash sync cable (with a 3.5mm to 6mm adapter for studio strobes), and the Nikon 10-pin cable for bodies like the D300s, D3, D4, etc. There are also cables available with a traditional PC Sync plug on the end.

Recently, these kits have actually started shipping with an RF-600 Tx, which are slightly different to the RF-602 Tx. The only difference is that the RF-602 Tx has a PC sync socket on it, and the RF-600 Tx doesn’t. This isn’t a huge deal for most people, but if you’re looking to use external sources (sound & light triggers, for example) to fire your flashes, you’ll need to make sure you get the RF-602 version transmitter.

Do note that while all the RF-602 Rx are identical, the RF-600/RF-602 Tx are brand specific.  They are available for both Nikon and Canon.  Either Tx will work with either brand, but if you don’t use your own brand, the Tx doesn’t see a half-press of the shutter button.  This means that if you have flashes that go into sleep mode or idle status, it won’t tell those flashes to wake up and when you take the shot nothing will happen, so you’ll have to manually press the trigger button yourself to make the flashes wake up & fire, and then you can carry on shooting.  It’s only a minor inconvenience, and not one you have to worry about if you get the right Tx for your brand of camera.

I’ve been using these for a little over 2 years now, and have never had a single misfire in that time that wasn’t my own fault – basically, I didn’t wait long enough for the flashes to recycle. I’ve shot these at 8fps for 30-40 image sequences, with half a dozen flashes, and they didn’t skip a beat. I’ve shot them 100ft away through 12ft of solid concrete and they still fired every time.

Alternatives

As this post is already getting pretty long, we’ll get into light modifiers (softboxes, umbrellas, beauty dishes, etc) in another article.  There are so many possible options out there, depending on what you want to shoot and the look you’re after that they really deserve a proper in-depth look.

That said, you can get some rather pleasing looks with a bare flash as a hard light source without any modifiers at all.  With that in mind, using the list above as a guide, you can pick up a complete flash setup for as low as about £65-80 (Yongnuo YN460-II, Konig Light Stand, Large Shoe Bracket, and a pair of RF-603 transceivers), and all of these items are easily available from eBay and online retailers.

At the higher end of the items listed above, you’re looking at around £165 (Yongnuo YN560-II, Manfrotto Nano Stand, Interfit Strobies XS bracket, and a pair of RF-603 transceivers), which will give you more versatility, stability, power and potential future upgrade options, as you will be able to use a much wider array of modifiers with the Strobies XS backet, and have a stand capable of taking the extra weight, but that’s still less than half the price of just going out and buying a Nikon SB-900 or Canon 580EX2 flash at current prices (and that’s just for the flash, without the stand, bracket, and radio triggers).

Of course, there are advantages to buying the manufacturer’s own brand top of the line flash units, but unless you already understand what those advantages are and why you need them, they’re probably overkill for those just getting into it.

One of the things we really go into, that will almost certainly confuse your camera’s meter, is flash.  This is essentially because your camera’s meter is only looking at the ambient light in the scene through the viewfinder.  As the flash isn’t going off constantly while the camera’s looking at the scene, it doesn’t know that it needs to account for it.

This is one of the circumstances under which a handheld incident light meter can prove extremely useful, although it is not the only time when it can prove to be an advantage.

So, how does an incident meter differ from a reflective meter?

Where a reflective light meter’s sensor looks at the amount of light reflecting off the surface of an object through the viewfinder, in order to determine an average exposure, an incident light meter actually looks at the light being emitted from a source and the sensor measures how much light is actually hitting it.

So, are these just for flash then?

Most light meters offer 2 or more different modes for measuring light – some have several advanced modes for metering all kinds of different types of lighting setups & combinations, but pretty much all of them have these two in common – one for measuring flash, and one for measuring ambient light.

The ambient light meter is as it sounds, it looks at the ambient light in the environment and feeds back a reading.  Typically you can measure this in one of two ways, either aperture priority or shutter priority.

In aperture priority mode, you tell the meter what ISO you’re using, what aperture you want to shoot at, it measures the light and tells you what shutter speed to use.  This is handy for situations where your depth of field is important, and you want to focus in on specific parts of your scene while letting the rest drift off out of focus.

In shutter priority mode, you tell the meter what ISO you’re using and what shutter speed you want to set and it tells you what aperture to use.  This is useful when you’re trying to either freeze or capture motion.  If you want to shoot at 1/4000th of a second to stop a runner in their tracks, or pan with the runner on a slightly longer exposure to give some motion blur to the background, shutter priority is where you want to be.

One thing to remember is that 18% grey means nothing to incident light meters.  That’s solely to do with reflective light meters and how your camera is attempting to see the light.  You’re only ever really going to get accurate metering on a camera’s reflective meter if your subject is actually holding an accurate 18% grey card (let’s ignore histograms for now).  Incident light meters just look at the amount of light hitting the sensor, and give you an appropriate reading based on the information you tell it (ISO and either aperture or shutter speed).

So, how would I use an incident meter differently than the reflective meter in the camera for ambient light?

As incident meters are looking at the amount of light they get hit by, that means that they need to be positioned where your subject is.  So, if you’re photographing somebody in the park, for example, you’d hold the light meter up to where their face will be.

There is debate about whether you should point the light meter at the light source itself, or back at your camera.  Personally, I find that there is no single answer and it’s a situational judgement call depending on the shot and the result you’re trying to achieve.  Typically, I will point the light meter towards the key light (whether that be the sun, a light on the wall in an interior, or at the main flash unit).

You press a button, and the meter feeds back your ISO, aperture and shutter speed.  Once you set your camera to manual mode and enter these settings, you should (in theory) get perfect exposures every time.  I say in theory, as it will depend on the lighting conditions under which you’re shooting, and how you’re using your meter.

As you’re in manual mode, if somebody turns one of the lights off in a room, or a cloud comes up and covers the sun, you’ll probably start to get underexposed images.  Likewise, if you meter when the lights are low or the cloud’s already in front of the sun, if the cloud goes away or more lights get turned on, now you’ll start to overexpose.

The light meter will give you back the settings you should be using under the lighting conditions you metered.  If those lighting conditions change, you should meter again.

If I have to keep going over to my subject to meter, isn’t that a lot more hassle than just using the camera’s reflective meter?

Personally I don’t think so, but it depends on what you’re shooting.  If you’re wandering around an event capturing moments as they happen, under varying lighting conditions, your camera’s built in meter is probably going to give you the best results – but it’s still a “best guess” (albeit a very educated one with modern DSLRs and final generation or two of 35mm SLRs).

If you are shooting under more controlled conditions, and are able to pose your subject, or have control over the light that you’re shooting under, a light meter is typically going to give you more accurate results consistently.

As to whether it’s more or less hassle or not, if you want accuracy and consistency using your camera’s reflective light meter, you’re going to need to have an 18% grey card with you.  Every time you need to meter, you’re going to have to get that card, hand it to your subject, have them hold it while you point your camera at it, fiddle with some settings, get the card back from your subject, put it away, and then shoot.  If you’re using an incident meter, assuming you don’t change your ISO and aperture (or shutter speed if you’re in shutter priority mode), all you need to do is walk up to your subject, press a button, walk back to where you’re shooting from, and enter the settings the meter has given you (or have an assistant meter and yell out what aperture or shutter speed you need to set).

Most of the time, I’m shooting under controlled conditions, it’s not typically “spur of the moment” events, and the timing is not critical.  Accuracy, however, is.

I get it now, so what about with flash?

Flash works a little bit differently to metering for ambient, as with flash your exposure is determined almost entirely by your aperture (and ISO), and not your shutter speed.

Typically, when your scene or subject is lit solely by flash, you’ll be in shutter priority mode.  You’ll give your meter a shutter speed (which is largely irrelevant, as noted above), press a button, fire your flash, and when the meter sees your flash go off, it tells you what aperture you need to set on your camera in order to achieve a good exposure.

Cool, but I want to shoot at f/4, and my meter’s telling me to use f/8.  What can I do?

Well, you have a few options here.  The first one is the obvious one, set your camera to f/8 and deal with the extra depth of field.  Sometimes you may be forced into this situation if you’re unable to use one of the other solutions suggested below.

As we know from the Inverse Square law, when we double the distance between the flash and the subject, we quarter the amount of power from that light hitting the subject.  Or, we lose two stops of light.  Doubling the distance of the flash from the subject and metering again should bring that f/8 right down to f/4 where we want to be.  But, as with changing your aperture above, this affects the quality of the light and how hard or soft the shadows are.

Another option is to lower the power on the flash.  If we’re currently at full power, dropping the flash down to 1/4 power also loses us two stops of light without changing the quality of the light and without affecting the shadows.  If your flash meters f/8 at 1/8th power, you’d need to drop down to 1/32nd power to lose two stops.  If your flash is already at its lowest possible power setting, there’s ways around that too.

If you can’t (or don’t want to) move your flash further from your subject, you don’t want to change your depth of field, and you’re already at the lowest flash power setting, you can drop your ISO.  If you’re shooting at ISO200, going to ISO50 (if your camera is capable of it) will lose you those two stops.

If your camera’s ISO can’t quite go low enough, you could also use Neutral Density.  You can either put ND gels over your flash head or you can use ND filters over your lens.  Either way will drop the amount of light emitted from the flash and seen by the camera by however many stops of ND you apply.

If you put 2 stops of ND gels over your flash, your meter should now tell you f/4 and everything’s good.  If, however, you put two stops of ND over the end of your lens, your flash meter will still tell you f/8 (as the flash itself isn’t being affected), so you need to remember that you have 2 stops of ND over your lens and compensate accordingly by opening up your aperture to f/4.

You could also combine some of the above solutions.  If your light meters f/8 @ ISO200 and your ISO only goes down to 100, you could lose one stop by dropping your ISO to 100, and then add just 1 stop of ND over the lens (or the flash).  Or you could be happy dealing with slightly more depth of field and set your aperture to f/5.6.  If you’re happy to settle for a tiny bit of extra sharpness, you could just move your flash about 40% further away instead of doubling the distance.  You’ve already lost one stop by going from ISO200 to ISO100, so now you only need to lose one more instead of two.

One thing you quickly learn about photography, is that everything is a compromise.  It’s a trade off between this or that, and when you take from somewhere you have to give back somewhere else in order to compensate.  Once you start to figure that out, where those compromises and trade-offs can be made, and find your preferred way of doing things, that’s when you start to develop your own style which makes your images stand out from everybody else’s.

Awesome! So, when else might an incident meter be useful?

One of the advantages of digital photography is that you can instantly see your results on the back of the camera.  You take a shot, you bring up the image review, you can check the histogram, and immediately correct any issues that may arise in your exposure.

The same cannot be said when shooting film.  I have several film cameras, some including rather fancy meters similar to those which we see in DSLRs, like my Nikon N90s (the camera which captured the image at the top of this article – metered with my Sekonic L718 light meter), and some which don’t have any kind of metering at all, like the 60 year old Agfa Isolette and the 80 year old Voigtlander Brilliant.

Even though my N90s has a built in meter that’s pretty reliable, it can still get confused – the same way DSLR meters do.  Using a light meter gets around those issues and helps me to get an accurate result every time, and I know that when the time comes to develop the film I’ll be getting exactly what I expected.  With cameras that don’t have a light meter at all, they’re pretty much essential.

So, with film, light meters are extremely useful, even if the camera has a built in meter, to help ensure accurate exposures, pretty much every time – when used correctly.

With digital, they’re not as essential as they are with film, as the histogram is a pretty wonderful tool (although still not necessarily completely accurate or perfect).  That said, they are a great time saver, even with digital, to help you get the shot that much faster when you know how to use one.

Speed and efficiency of workflow on a shoot can make the difference between a nice happy and relaxed portrait session, and your subject looking bored and uncomfortable halfway through the set and in a large number of the images.

Sorry, what?

To really make sense of what metering is, you need to understand firstly what the meter is trying to do with the readings it gets and then the different metering modes available in your camera (the different ways it can get those readings in the first place).

I’m trying to keep the definitions of how each mode works and what they do as broad as possible, as every manufacturer does things just slightly differently in order to achieve the desired results.  Even different models of camera from the same manufacturer can work slightly differently – see your manual for details.

Ok, so you say my camera looks at the light reflected off a subject?

Yes, the meter inside your camera is what’s known as a reflective meter.  This is pretty much as it sounds, it takes a reading based off the amount of light reflected off either part or all of your scene.  Different objects reflect back different amounts of light.  For example, a black T-Shirt is going to reflect less light than a white one.

What it then tries to do is figure out an exposure value that would allow the camera to represent all this light at a brightness level of 18% grey (which is the mid point between pure black and pure white).

It works this way in order to try to have some consistency in the brightness levels from shot to shot, under potentially very different lighting conditions, and to try to retain as much detail as possible in both the shadow and highlight areas of the scene.  But, it can be confused depending on what you’re shooting.

I’m with you so far.  So what are metering modes?

Metering modes are the different ways you can tell your camera to “see” the light and determine its readings.

There are three main metering modes typically available on DSLRs; Spot metering, Centre weighted metering, and Matrix metering (or evaluative metering, depending on your particular brand of camera – but for all intents and purposes they’re the same thing).

Matrix metering, I’ve heard of that one!

Let’s have a look at matrix or evaluative metering first then.  This is the one that most people will probably use for the majority of the images they shoot, and it’s typically the one your camera is set to by default when you purchase it.  In this mode, your camera basically looks at the entire scene, it then tries to figure out an average value for the brightness levels represented in your scene, and determines an exposure value to make the scene’s overall brightness average out to 18% grey.  This is a simplified explanation, but it demonstrates the point.  There’s a little more information on this down at the bottom.

As an example, let’s say you’re spending the day at the park with your family.  Your significant other is wearing a rather fetching bright yellow number, your toddler is with you wearing his spiderman suit, it’s a glorious day with a few white clouds darted about the sky, there’s grass and trees in the background, and they’re on a near black footpath.  Then, you bring up your camera to take a shot.

The camera will look at all the brightness values of each of these areas around the frame, average them all out, and then determine an exposure value that will make this average brightness level become 18% grey.  This way the camera can try to retain as much detail as possible in both the bright highlights (the bright yellow shirt/dress/whatever, the fluffy white clouds, etc) as well as in the darker areas (the dark footpath and the deep reds and blues in the spider suit) when you actually press the shutter.

If you’re shooting in one of the fully or semi automatic modes (P, A & S for Nikon or P, Av and Tv for Canon) it will try to set what it thinks is the right combination of aperture & shutter speed, based off your ISO, in order to achieve that exposure value.  In manual mode, the meter just tells you if you’re over or underexposed, by how many stops or fractions of a stop, and lets you determine whether you want to adjust your ISO, aperture or shutter speed in order to “zero it out” and get the exposure value the camera tells you is the “correct” one.

The majority of the time, matrix metering (or evaluative metering) is the method that will get you the best overall result, but this is also the metering mode which can get confused easily if you’re shooting very contrasty scenes or shooting a scene that contains an unusually high amount of particular bright or dark areas.  This is why you may find that the nice portrait on the beach turns into a beautifully blue sky & ocean with your subject a pure black silhouette, as in the example below of the lovely Collette Von Tora (not that you can tell in this image).

Alternatively, if you’re shooting against a dark background that is in shade and your subject is in bright sunlight, it may give you a beautifully exposed background while turning your subject pure white.

Ahhh, ok, so what can we do to fix this?

In the sample image above, the only way to really get a good exposure on Collette while maintaining the exposure in the sky is to pop her with flash (which is what we did on that shoot).

But let’s say we’re not that bothered about whether the entire scene is well exposed, and we’re just concerned with our primary subject and we don’t have a flash with us, or it’s impractical.  Well, that’s where centre weighted metering and spot metering come in.

In spot metering mode the camera looks at a very tiny section of the image, and reads only the light reflected by whatever that very small section is covering.  Spot metering is generally associated more with the Zone System, developed by Ansel Adams based off the work of Fred Archer.  While we’re not going to get deeply into the zone system here, there are other times when spot metering can be very handy.  The above possibly being one of them if we weren’t bothered about having detail in the sky.

Traditionally, in spot metering mode, the camera just looks at the brightness levels in a small circle covering about 3mm diameter of the image in the dead centre of the frame, and then formulates an exposure value based entirely on the reading of that small area.  On more modern recent cameras, this 3mm circle will follow your autofocus point.  So, if you’re using a single AF point other than the centre one, in order to lock focus onto your subject, the meter will be looking at the same part of the frame to determine what brightness levels it needs to pay attention to.  When you change your AF point from the centre, that 3mm circular area moves along with it.

This is a handy advancement in the way things work, as you typically want to use the AF point nearest to the part of the frame you want to focus on, and as it’s the point of focus, that’s what you’ll want to be metering too.

In this example, of a pleasant old chap I met at Blackpool Zoo, I encountered a similar problem to that which I faced with Collette.  Bright cloudy sky (although not quite as bright as the clear cloudless sky in image above), and a dark subject that appeared near black if I’d allowed the camera to expose the scene all by itself using matrix metering mode, and as he was around 35-40ft away from me (and about 10-15ft above me), there wasn’t much chance of throwing out some flash.

Our primary focus here was the orangutan, not the environment around or behind him. As such, it didn’t really matter if our sky was blown out slightly (although, as I was shooting RAW, I was able to pull back a tiny bit of detail so it wasn’t completely white) and I wasn’t too bothered if the wooden frame of the climbing apparatus was adequately exposed either (as it was also slightly brighter than the orangutan, I didn’t want it to contribute to the exposure either).

Spot metering was the answer here. In spot metering mode, I placed my autofocus point directly over one of the areas of the orangutan that was lit by sunlight. I figured this was the same approximate brightness as 18% grey. With my ISO at 200, and my aperture set to give me the depth of field I required, this allowed me to get a shutter speed that would give me adequate exposure on the subject, regardless of what else may be in the scene.

With my ISO, aperture and shutter speed set, I was now free to compose the image how I wanted, and be able to make the photo knowing that my exposure for the subject would be good.

That makes sense, so what’s centre weighted metering?

Centre weighted metering is a bit of a hybrid between matrix/evaluative metering and spot metering.  Centre weighted metering does look at the entire scene, however it primarily focuses on an area in the centre of the frame (or, again, following your AF point), and gives that area more “weight” than the outside of the scene when determining how to expose.

The camera I primarily use is the Nikon D300s.  On the D300s, the camera has a default value of 8mm set for the diameter of this circle (which also moves along with the AF point), although this setting can be changed via the camera’s menu system to be 6mm, 8mm, 10mm, 13mm or even average the entire frame.  The default setting, and whether you can even change it or not will vary depending upon the make and model of your camera – again, see your manual.

Anyway, let’s go back to our day out at the park.  There you are shooting your son, but instead of a spiderman outfit, he’s wearing standard blue jeans and a grey t-shirt.  We have a similar arrangement with bright blue sky and dark ground, but matrix metering isn’t quite giving us what we want.  Perhaps the sky is too bright, or the ground too dark, and it’s throwing things off a little bit.

Here spot metering may be impractical as we’re not entirely sure how closely the different areas of our subject or his clothes represent an 18% grey level of brightness, and we really don’t need to be that precise anyway.  We just want to have a nicely exposed image of the boy, and it doesn’t matter if our sun is slightly overexposed, or our ground underexposed.

If we set our camera to centre weighted metering mode, and set our AF point to somewhere around our subject’s face, when we now bring up the camera and frame it on our subject, our camera is still metering the entire scene, however the areas contained within that circular area around our AF point are receiving about 75% of the weight (influence) of the whole shot.  The other 25% is the rest of the scene outside that circular area.

In theory, this gives us a nicely averaged exposure on our subject, without giving the outside areas so much importance.  This was generally the most common method of metering 35mm cameras for general use until matrix metering came along.

You said that centre weighted metering can be configured to look at the whole scene, so how is that different from matrix metering?

Well, matrix metering has come a long way over the years.  Initially it pretty much was just looking at the entire scene and averaging things out, as I would get on my D300s if I configured CW metering mode to cover the entire viewfinder.  These days matrix metering takes a lot more of the scene’s information into account in order to determine an accurate exposure.

Nikon’s current matrix metering system, “3D Color Matrix Metering II”, takes many other factors into account in order to determine what it is you’re actually trying to get the exposure of, and uses what it perceives to be in focus to help determine a valid exposure.  Things like the distance at which your lens is focused (with compatible lenses – which is most modern Nikon glass), the actual colour of items within the scene (one of the drawbacks of spot & CW metering is that they only “see” in simple grey brightness levels), exploring individual RGB values of everything in the shot.  The meter then accesses an internal database of over 30,000 images in order to compare and try to give you the most accurate exposure possible (and it does this almost instantaneously).

Evaluative metering, as it is called on some other camera systems, has similar methods that it utilises in order to try to determine the correct exposure, but, as mentioned above, it can still get confused in scenes that contain a very high dynamic range, a lot of contrast or when a major part of the image is an extremely bright or dark area.

So my camera’s pretty smart, huh?

Generally speaking, when it comes to metering, yes, it can be.

As I stated at the top of this article, matrix or evaluative metering is the mode you’ll want to be in for the vast majority of your shooting.  On the current generation of bodies (and those newly announced ones waiting to hit the streets) the metering systems are very advanced, and will often just know what you’re trying to do, even if you don’t.

Unless you know you have a specific need to jump into spot or centre weighted metering modes (and only experience can really tell you when this is), you can pretty much stay in matrix metering mode the whole time and not have to worry about it.

Together these three settings comprise your exposure triangle, and while you can achieve the same exposure value with different combinations of these three components, you won’t necessarily see the same results.

Changing any of these settings will have a different consequence, and you’ll have to adjust something else in order to compensate.  Ultimately your final image will be a trade-off between depth of field (aperture), noise level (ISO) and how much motion you want to capture or freeze (shutter speed).

There are other things which can affect your exposure, but we’ll get to those later on at the end.

Ok, so how do I figure out what my exposure should be then?

What you need to do is a process called metering.

Temporarily put your camera into P mode (yes, yes, I know, I said temporarily!), and it should work out a shutter speed and aperture (maybe ISO too, depending on how your camera is configured) that would give you an accurate exposure for your scene (at least, that’s the theory).

If we set our camera on a tripod and point it at a mostly static landscape scene on a very dull day, the camera may have chosen the following settings.

• ISO400
• f/5.6
• 1/60th of a second

If we take a test shot, we can see that we have a nicely exposed image with details in the highlights, details in the shadows, and lovely midtones (that doesn’t always happen in the real world, but for the sake of this example let’s assume your camera metered correctly).

Now if we pop it into manual mode, enter those same settings, take another shot, we can see that we get the exact same image.  But, what if we want to get a shallower depth of field on a subject in the foreground?  Or a much larger depth of field to capture the whole landscape?  Or we want to freeze a moving subject?  Or to capture the motion of it?

Yeah, what about that?

Let’s look at the first example, decreasing our depth of field.  Here you’d have to open up your aperture (remember, smaller number = larger aperture = more light hitting your sensor) in order to get a shallower depth of field.  This has the side effect of letting in more light.  If we look at the following list, we can see our whole stop aperture values starting at f/1 all the way to f/32.

• f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32

There’s our lens at its current setting, right in the middle.  The numbers to the left of this give us a progressively larger aperture with a shallower depth of field, and each allows one stop more light to enter our lens than the number directly to its right.  If we go the other way, the larger numbers give us a progressively smaller aperture, a deeper depth of field, and allow one stop less light than the number directly to its left.

This is a list of our whole stop ISO values.  The higher the number, the more light our sensor is sensitive to, at the expense of an increased level of noise.  Some cameras, such as the Nikon D3s and D4, will go much higher than ISO25600.

• 50, 100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600

There’s our setting, ISO400, highlighted in bold.  Each number to the left is 1 stop less sensitive (less light capturing ability) than the number immediately to its right.  Each number to the right is 1 stop more sensitive (more light capturing ability) than the number immediately to its left.  The further right you go, the more noise you get.  The further left you go, the less noise you get.

Shutter speeds increase and decrease the amount of light in the same way as ISO, by doubling or halving.  There are far more shutter speed options, going all the way from 1/8000th of a second to 30 seconds (and longer with some cameras or external timers).

• 1/8000, 1/4000, 1/2000, 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1, 2, 4, 8, 15, 30 (duration in seconds, or fractions of)

You’ll see that the fractions aren’t always exactly halves, for example going from 1/125th to 1/60th, or from 1/15th to 1/8th.  These numbers are rounded off simply for the sake of mathematical simplicity.  For all intents and purposes, the numbers above are each 1 stop apart.  As we go left, each shutter speed lets in half the amount of light as the number directly to its right, and as we go right, each shutter speed lets in twice as much light as the number directly to its left.

Remember, when we double or half the amount of light, we are increasing or decreasing the light by a stop.

So, let’s have a look at the settings our camera suggested we use again.

• ISO400
• f/5.6
• 1/60th of a second

We see a nice tree in the foreground of our landscape, and we want a shallower depth of field on that tree so we can blur out the background, in order to be able to really impress that tree upon our viewer.  Our lens opens up all the way to f/2, great, nice and shallow.  If we go from f/5.6 to f/2 and change no other settings, we have the depth of field we want, but we have also gained 3 stops of light (8x as much light).  This means our shot will now be 3 stops overexposed.

Now, we have to lose light somewhere else.

This presents us with 3 options.  We can either lower our ISO, speed up our shutter, or both.  We need to lose 3 stops of light, this means we can take our shutter speed from 1/60th to 1/500th of  second.  If we take a shot now, we can see we get the exact same exposure value (“brightness level”) as we originally did, but with a much shallower depth of field.

• ISO400
• f/2
• 1/500th of a second

The image looks ok, but we do have a little bit more noise than we’d like, so let’s see what else we could do.

The hypothetical camera that we’re using has a minimum ISO value of 100.  So, with our camera set back to ISO400 at 1/60th of a second, when we set our aperture to f/2 we again need to lose three stops of light, and we want to get rid of some noise.  So, we can drop down to ISO100.  We would like to go lower, but this is as low as our camera allows us to go.

This only loses us two stops of light (see the list of ISO values above), but we have a much cleaner image than we did before with less noise.  Now we can bump our shutter speed from 1/60th to 1/125th to lose that last stop of light.

• ISO100
• f/2
• 1/125th of a second

If we take another shot now, we’ll see that once again we have the exact same exposure value, with our shallow depth of field, but with less noise than the image above.

Ok, fantastic, but there’s this really cool waterfall behind the tree that I’d love to get in focus, and I’d really like to be able to capture the motion of the water a bit if I can, what can we do?

Well, as we know, decreasing the size of our aperture (larger number) will increase our depth of field.  The lens we’re using goes all the way up to f/22, and that’s probably plenty enough depth of field for what we want.

If we’re still at the settings of our last shot, and we go down to f/22 in order to maximise the depth of field we can get from our lens, we have lost a whopping 7 stops of light.  Now, we could bump our ISO up to ISO12800, and get the following settings.

• ISO12800
• f/22
• 1/125th of a second

We’d get a well exposed image, same as all of our examples above, but we’d get far more noise than we would at ISO100, and lose a lot of detail.  It wouldn’t look anywhere near as clean as the other images we’ve shot.  We also would still be shooting at 1/125th of a second, which wouldn’t allow us to capture much motion from the beautiful waterfall.

So, let’s start again, if we keep our ISO at 100 in order to minimise the amount of noise, we change our aperture to f/22, then we need to gain 7 stops back on the shutter speed.  At 1/125th of a second, we need to slow the shutter all the way down to 1 second in order to get that 7 stops of light back and get a good exposure.

• ISO100
• f/22
• 1 Second

Now we have a really deep depth of field, allowing us to capture the tree in the foreground of our scene, the lovely waterfall behind it, the clouds in the sky several miles behind that and have everything in focus.  As our shutter is open for an entire second, the speed of the water in the waterfall means we have captured the motion and the path of the water falling down it and along the river.  As our ISO is very low at only 100, we also have a very clean image with virtually no noise, so we can see every detail.

Remember, we have not moved our camera, the light has not changed much, it’s a fairly dull day, so even though the sun has moved, the clouds have given us some consistency.

Given that the light has not changed, and our scene has not changed, every combination of settings listed above will give us a “correct” exposure in this instance, given how our camera initially metered the scene.  Every time we changed one setting to give us a certain effect, we changed another setting to compensate for the increase or decrease in light recorded by our camera.

Which one is the right image depends entirely upon you and what you’re trying to capture.  Whether we increase or decrease the depth of field, capture more or less motion, or have more or less noise in our image are creative decisions, and it’s a balancing act that allows you to get the results you desire.

This is one of the reasons why automatic exposure modes often aren’t a great idea, and why you don’t always get the results you expect!

My camera has a whole bunch of other numbers in between all the ISO, aperture and shutter speed values you listed above, what are those?

These will either be 1/3rd or 1/2 stop increments, depending on which camera you use and how you have it configured.

The principle is the same, you lose a 1/3rd of a stop of light by adjusting one thing, you have to gain it back by adjusting something else, you’re just dealing with more specific amounts of light, depth of field, noise and motion in order to really nail down the shot you want to get.

Before you go, earlier you said there was something else that could affect our exposure?

Yes, I did.  There is one other main method of changing your exposure and that is by the use of neutral density filters.  Sometimes you want to shoot at a shallow depth of field in the middle of the day and capture some motion at the same time.  When your ISO is as low as it’ll go, if your image is still overexposed, the only other reliable way to decrease the amount of light entering your lens is via  a neutral density filter.  On a bright day, even at f/22 and ISO100, you may not be able to get anywhere close to a 1 second exposure, and you may want to go even slower if you want to capture some motion.

When I say a “reliable way”, I mean predictable and measurable.  Neutral density filters are typically available at varying strengths from 1 stop all the way to 10 stops (and sometimes even more!), and will allow you to shoot at wide open apertures for decreased depth of field, and longer shutter speeds to capture that motion.

Circular polarising filters will also decrease the amount of light entering your lens, and allow for longer shutter speeds at smaller apertures, but the amount of light lost on polarising filters will vary from brand to brand and from price point to price point.  Typically, the better the brand, and the more expensive the filter, the less light is lost.

This might make the cheaper filters sound more appealing if you’re looking to lose more light, however it comes at the expense of a loss of sharpness and a much increased risk of flare due to the lack of high end coatings used on the filter.  Your best bet is to get the highest end circular polariser you can, and if you need to drop the light even more, stack it with ND filters.

But, we’ll get deeper into using both of those in other articles.

This morning I developed that film!

So, what did I learn from this first roll?

• For a start, I’d forgotten how solid the N90s feels and sounds when you hit that shutter. It’s a clunk that just isn’t there with the DSLRs (probably due to the extra noise from the motordrive progressing the film), and it just fills you with positivity and happy feelings.
• I definitely need more practise loading rolls of film onto the spools inside the changing bag. It probably took me about 6 or 7 goes to get it all on without screwing it up. Other than that, it was a simple process. Cracking open the cannister, removing the film, cutting off the leader, cutting the end of the film off the cannister’s spool, getting it on the spindle with the other spool and putting the developing tank all back together was pretty much a doddle.
• I learned that I need to buy new containers for measuring liquid. Putting 37.5ml of Ilfostop into a bottle with a 1cc syringe isn’t all that fun.
• I discovered how quickly time flies when you’re agitating (inverting) the developing tank, and how slow it goes when you’re watching the clock waiting for the next time you’re supposed to do it (and again how quickly it goes when you get distracted from watching the clock).
• I definitely need more than one jug to pour liquids into when they’re ready to come out of the tank.  30-60 second intervals between agitations is barely enough time to pour it back in the bottle and rinse out the jug.
• I need to be more prepared.  I completely forgot clips to hang the roll, so had a mad dash looking for something that would work while it was rinsing.  I also had no idea where I was going to be storing these negatives (yup, I forgot to buy protective sleeves).
• I really have to get a wetting agent, despite several local photographers telling me “nah, our water here’s fine”.  You may be able to notice in the image at the top of this article that there are one or two water spots.  They appear on pretty much every frame (but, hey I knew I’d screw up a roll or six which is why I bought the cheap stuff).  It was suggested to me today that raising the temperature of the rinsing water should help to resolve this without a wetting agent.
• My scanner is just awful for working with negatives (again, see the image at the top), but then it was never designed for this purpose.  It captures almost zero shadow deal, instead just fading it off to black.  This means when I invert the negative on the computer, white gets blown out about 3 stops higher than it should.  It also has terrible banding.
• The Nikon N90s manual lies.  It claims a 1/250th of a second max sync speed, however, I couldn’t get beyond 1/200 without seeing black bars across the bottom.
• I also learned, later in the day, that banging the developing tank against the bathroom sink at 7am to loosen air bubbles while my wife is trying to sleep probably wasn’t the best move I made today.

I’ve already been out and bought new measuring jugs today (although they still don’t allow measurements quite as small as I need – will continue to hunt!), bought some more suitable bulldog clips (I did manage to find something I could use this morning, but now I have proper clips), and I have now been out and bought some slide sleeves and a ring binder in which to put them (I bought both 35mm as well as 120 in preparation for shooting some MF).

The wetting agent will have to be ordered online.  I went into our two local photography shops, and neither had any available (both normally carry it, but both were sold out).  One was expecting some next week, but they typically say that whenever I ask for something they don’t have.

As far as the scanner, I should be picking up an Epson Perfection V700 this week, so I’ll be able to scan them all in properly.  Mine is just absolutely useless.

So that’s it for now.  I’m quite pleased with how the negatives look against a backlight, lots of shadow & highlight detail, not so much with the scans, but that should be resolved soon and then hopefully I can show you what they’re supposed to look like.  I’m off to do some scouting and location lighting tests with a friend tomorrow for a shoot next week, so will be taking a couple of rolls of the Kentmere 100 with me.

Will keep y’all posted!

PS. Just for my own reference here….

• Camera : Nikon N90s
• Lens : Nikon 50mm f/1.8D
• Film : Kentmere ASA100
• Developer : Ilfosol 3 / 1:9 / 5 Mins, agitate 4 times at the beginning of every minute (24°C)
• Stop : Ilfostop / 1:19 / 30 Sec, agitate the whole time
• Fixer : Ilford Rapid Fixer / 1:4 / 5 Mins, agitate 4 times every 30 seconds

And I’ll pop up a link to some of the images once I can get them scanned in properly.

Essentially, the Inverse Square Law (let’s just call it the ISL from here, or this could get annoying) states that any point source which spreads its influence equally in all directions will see the strength of that influence reduced in a manner inversely proportional to the square of the difference in distance (or to put it more simply, when you double the distance from the source, you quarter the strength (1/2²) of that point source’s influence, when you triple the distance you get 1/9th (1/3²) the power, quadruple the distance you get 1/16th (1/4²) the power, and so on).

This is simply geometrical fact.  Point sources such as gravitational force, light, sound, radiation and electricity all conform to the ISL.  If the earth were twice the diameter it currently is, yet had the same mass, we’d weigh a quarter of what we currently do (much to the delight of some).  If we cut the distance between the Earth and the Sun in half, daytime would be 4x as bright (although, as a nasty side effect to the improvement in British weather, we’d cook from the heat!).

So, how does that apply to us, as photographers?

Well, you’ll notice one of the things I mentioned above that’s affected by the ISL is light, and given that photography depends entirely upon light (or a lack thereof) that’s a bit of a biggy, especially if you use flash (although the principle still applies to ambient light shooters too).

Let’s have a look at why this happens, with the help of the image below.

Remember, the point source spreads its influence equally in all directions.  So, given that the point source is at the centre of the sphere, at a set distance you’ll get the exact same readings from any point on the surface of that sphere.  You can see above that as the sphere grows it has to spread that influence out to cover the new larger surface area, which results in a reduction of power.

When you double the radius or diameter of the sphere, the surface area is multipled by 4.  The inverse of this is 1/4, so when you double the distance, you get 1/4 the power.

Oddly enough, while making the above image, I discovered that radial gradients (or “ramps” as AE calls them) can also obey the ISL.

I think I’m starting to understand, so how does that work in practical terms?

For our purposes, there are two basic things to keep in mind.  Light falls off from the source (it gets weaker the further away it is) and diminishes at a predictable rate, and the greater the distance between the light source and your subject, the more even spread of light your flash will provide over a larger area (at the expense of power).

Woah, wait, let’s take this slowly

Ok, let’s have a look at the first bit.  Light falling off and diminishing at a predictable rate.

Let’s assume that we have a bare flash which meters f/16 at a distance of 10ft from our subject.  We lose approximately a stop of light every time we multiply the distance by 1.4, and we lose two stops whenever we double the distance.  With our light metering f/16 at 10ft, it would meter f/11 at 14ft (a loss of 1 stop, or 1/2 as much light), and f/8 at around 20ft (a loss of 2 stops, or 1/4 of the light.

It stands to reason, then, that this also works the other way, if we divide the distance by 1.4, we gain a stop of light, and if we divide the distance by 2, we gain two stops of light.  So, at 7ft, we meter f/22 (a gain of 1 stop, or double the light), and at 5ft we meter f/32 (a gain of 2 stops, or 4x as much light).

You have just learned how to increase or decrease the amount of light hitting your subject from your light without adjusting any settings on your camera, and without adjusting the flash’s power setting.  This can have other side effects which may or may not be desired.  One is the angle and convergence of shadows casting onto and by your subject, another brings us on to point number two.

Ok, hit me!

In the second point I mentioned that the greater the distance between your light source and your subject, the more even the spread of light it provides.  This is because the further away you get from your light source, the slower the light it emits falls off.

Let’s look at our example again.  At 5ft, we meter f/32, at 7ft we meter f/22, at 10ft we meter f/16, at 14ft we meter f/11 and at 20ft we meter f/8.

At 5ft, we lose a whole stop of light 2ft further away from our subject.  At 14ft, we have 6ft before we lose another stop.  This is handy to know if you’re shooting several people at once.  The further away your lights are from the subject, the more evenly lit each of your subjects will be as they stand closer to or further away from the light relative to each other.

Look at the images below for an example.  If you’re doing a group portrait of 3 people stood side by side, your light is on the left, and your closest subject is 5ft away from the light, metering at f/32, your subject furthest from the light may be 10-11ft away.

In reality, you probably wouldn’t light a group of people this way, but just for the sake of demonstration, let’s say you would.

If your lens is set to f/32, the person on the left will meter beautifully and be accurately exposed, the person in the middle will be about a stop and a half underexposed, and the person on the right will be over 2 stops underexposed.  If you  went the other way and set your lens to about f/16 to expose the subject on the far right, the person closest to the light will probably be pure white with no detail at all.

We have over 2 stops of difference between a distance of 5ft and 11ft from the light source, or over 4 times as much light on our closest subject.

If we move all our subjects about 15ft to the right (our right, their left), you can see that they’re all lit fairly similarly.

In fact, the variance here between the closest and furthest subject is only about a 20-30% difference in the amount of light received (we don’t lose another whole stop of light until we’re 28ft away from our light).  This means that all three subjects are going to receive a fairly similar amount of exposure (much less than a stop of difference between the nearest and farthest subject).  You could bump up the amount of light on the subject furthest from the light with a little bit of fill, or you could position your subjects so that the one with the darkest skin tone is closer to the light, and the one with the lightest skin tone is furthest away, then all will appear more consistent in your shot.

If we set our aperture somewhere between f/5.6 and f/8 we can get a fairly even exposure on all three subjects.

Aha, I get it now.  So, how might this affect the background behind our subject?

Because the falloff of light from its source is predictable, you can also position your lights, subject and background in positions relative to each other so that you can turn a white background into a grey or even black background.  If your subject meters f/8 at a distance of 4ft from your lights, your background 12ft behind your subject (16ft away from the light) would only be metering at about f/4 and become very dark grey (even if it’s actually white in reality).

If your subject stepped forward by 2ft, and you knocked your flash power down by 2 stops, so that your subject still metered f/8, your background would now be metering f/2 and virtually black.

Or, you can position them in such a way that your background receives about the same amount of light as your subject.  If your subject is 20ft away from your light source, and the background is only 2ft behind your subject, both will receive a similar amount of light (of course, your subject will also now cast a shadow on the background as they’re so close – which may or may not be desirable – this is why you sometimes need to light your background separately from your subject).

So, how does this work for ambient light?

It works in exactly the same way.  Let’s say you’re shooting by a large window or inside a doorway on a cloudy, but still rather bright, day.  If your subject is 2ft away from the window, and is metering f/8, you would see a reading of f/4 if you moved your subject 4ft away from the window, and you would see a reading of f/2 if you moved them 8ft away from the window.  This happens because the window, rather than the sky, has become your light source, so what matters is the distance between your subject and the window (or doorway).

So what about shooting outside in ambient light then?  If I’m outside on a sunny day and my subject is 6ft away from me, why are the people 50ft behind them just as bright?

When the sun is your light source, the inverse square law still applies, however it involves such huge distances that you don’t notice any difference.  The Sun is approximately 93 million miles away from the Earth.

In order to lose just one stop of light, the Earth would need to be about another 37 million miles further away from the Sun (at which point your camera would probably seize up anyway with it being so cold n’ all, although that probably wouldn’t be your biggest concern).  A difference of only 50ft is so small it can’t even be measured when compared to 93 million miles.

Well, that makes sense, I think.  I’m going to read through all that again a couple of times, and get back to you!

Don’t worry if it’s not fully sinking in just yet.  While the Inverse Square Law is a fairly basic concept, its implications in the photographic world can be a bit difficult thing to initially grasp.  Just experiment.  The more you play around and practise, the more you’ll understand it, and one day it’ll just click, and the whole thing will make complete sense.

Happy shooting, and if anything above confused you even more than it helped you and you want to ask further questions, or you notice that I made any big fat obvious mistakes in this article please post a comment below.

I did not make this choice to garner praise, nor criticism (however much a certainty that may be), nor am I doing it in some sort of hipster-like attempt to “fit in” – if anything, the revival and popularity of film in the last couple of years has made the whole idea slightly less appealing and much more expensive!.  But, it’s just something I want to do.

So, why am I shooting film again?

In short, going through the whole process with film was something I was keen on doing right from the start.  When I made the switch to digital SLRs about 10 years ago, I went into it full steam ahead – always disappointed that I felt my film experience was “incomplete”.

Despite all the doom & gloom and the “it’ll never be as good as film” naysayers, I saw the potential of digital and knew that this would be taking over the world very quickly.  I was right, it did.  Within just a couple of years, many people I knew now owned a Nikon D70, Canon 300D, 10D or 20D (and most of them were just taking snaps of the family, their pets or holidays in far off exotic locations).

The likes of Facebook and Twitter did not yet exist, but already people wanted to share the photographs they were creating with a wider audience and long lost relatives on the other side of the planet, posting on many forums relating to the topics that featured in their images, the “nice pic” brigade was born, but you could still get very honest and valuable critique on a few select photography forums.

Digital’s future was inevitable, and I wanted to try to stay ahead of the curve.

The obvious question then, why now?

I’d intended to start shooting film again years ago.  I actually never really intended to drop it completely, it just worked out that way.  Since going digital, I’ve moved house three times, switched from one continent to another, I’ve never found a lab that could produce a consistent level of quality at a price I was willing to pay, and digital just became so reliable, simple, and quick (the instant gratification of seeing how your photographs are coming together on that tiny LCD on the back of the camera never completely disappears – even when you know it’s going to be right before you hit the shutter).

This year, however, I’ve been rearranging my priorities, and have found that I now have a little time to put back into shooting film once again, to try to further progress along on that journey I’d started years ago.  While the principles of photography remain the same, shooting film is just different to shooting digital.  I suppose it’s like owning both a car and a bicycle.  Sure, the car’s practical, it gets its daily use, they both get you from A to B, but sometimes it’s just nice to go out in the countryside for a quiet ride.

So, I’m not trying to “relive the good old days”, It’s unlikely to be something I’ll use with a paying client, it’s not some advertising gimmick to make myself stand out from the other photographers in the area,  but sometimes you just want to just limit your gear and your technology (certainly makes for a lighter camera bag) and go out there and make images.

Ever since getting the Nikon D100, shortly after its initial release in 2002, I’ve been exclusively digital and my N90s has lived in one of various drawers, boxes and camera bags during the last 3 house moves.  It still even has a roll of el-Cheapo Kodak something or other other sitting half unused inside it (I’ll have to finish that off and get it developed, because I’m kinda curious what I was last shooting with it).

A couple of years ago I picked up an 1932 Voigtlander Brilliant to have a play with some TTV photography.  TTV is sort of a precursor to the iPhone photography we see today with the multitude of apps available to make your crisp clean beautifully exposed images look like they were shot through an old dirty stocking.

Then, during 2011, a friend at Lancaster Photographic Society, who’d sold all his medium format gear several years beforehand, gave me a couple of dozen rolls of 120 film he’d found laying around in a box.  It’s a varied mix of Ilford PANF, FP4 and HP5, all quite a way beyond various dates of expiry.

If I actually want to use it with film, the Voigtlander needs a little TLC.  The shutter speed timings are way off (if I set it for 1/2 a second exposure, it lasts about 4 seconds), and I don’t have the time or knowledge to fix it at the moment.  Not too long ago I managed to get hold of an Agfa Isolette for an extremely good price, which also just happens to take 120 film.

I still have all the rolls of 120 film, kept nice and cool in their box, having had the urge to go out and use some of it but never the time.  This year, I’m making the time.

With the decline in the numbers of decent places to get film developed, the typical price for development has become rather high (today I was quoted £12 to develop a 36 exposure roll of 35mm!).  I figured it would ultimately be less expensive to learn to develop my own film (and much more fun too!).  As I’ve not shot 120 film before, and not used either of those cameras before (regardless of one not being too terribly accurate), I’m relearning film with something I know; My trusty old N90s.

So, a few days ago I pick up a couple of rolls of 35mm Ilford FP4, along with Ilfosol 3 developer, Ilfostop, and Ilford Rapid Fixer.  I’ve also ordered a pack of 10 rolls of Kentmere 100 film too (as I know I’m going to mess up my first few rolls, so I figured I’d do it with rolls that cost half as much as the lovely FP4), and I’ll be picking up my developing tank in a couple of days.

As I’ve never yet developed my own film, I’m going to be documenting my adventures so you can all have a good laugh at my expense, and hopefully learn from the mistakes I will inevitably make.

So, watch this space.

It is important, right at the very start of this, to understand what it is not. A stop of light is not a fixed quantity. How much a stop is all depends on how much light you have to begin with.

It is also important to note that there’s quite a lot of information below, for what is a fairly simple and straightforward principle, but once you start to soak it in, it just comes naturally and you’ll be adding and taking away stops of light from your exposure without even thinking about it.

So, what is a stop of light?

Put simply, a stop of light is either a doubling or halving of an amount of light, depending on whether you’re adding a stop or taking it away. This is why, when you have one light at a set distance from your subject, adding another identical light at the same position increases the output by a stop, but adding two does not increase it by two stops.

The fact that it is a ratio of light also explains why changing your ISO, aperture or shutter speed all have a very predictable effect on the images you shoot.

Let’s assume, for a minute, that we have a constant light source (LED, tungsten, compact flourescent, whatever, it doesn’t matter) that outputs X amount of light at maximum power. Exactly how much X is doesn’t really matter, as long as it remains consistent throughout the example.

If our light is set to maximum power (X), and we want to add a stop of light, we can simply add a second identical light. We are now shooting at a power of 2X. If we now wanted to increase this amount of light by another stop on top of that, we would have to add two more lights. Remember, when we add a stop, we double the amount of light, and double of two lights is four lights. We are now shooting at 4X power, or 2 stops brighter.  If we have one light at maximum power and we want to add 4 stops of light, we now need 16 lights instead of our original one!

If our one light is currently at maximum power, and we want to take away a stop of light, we simply dial it down to half (1/2 power). If we want to take away a second stop of light we dial it down to half of a half – otherwise known as a quarter (or 1/4 power).

The same principle applies to flash & studio strobes too. A Nikon SB-900 speedlight at maximum power is nowhere near the output of something like a Bowens Gemini 500 Pro at maximum power, but if you want to dial down the SB-900 by a stop, you cut the power in half. Similarly, if you want to dial the Bowens down by a stop, again, you cut the power in half.  If you’re already at maximum power and want to add a stop, you add another identical light and set them both to maximum power (or replace it with a more powerful light!)

Moving the lights closer to or further away from your subject will also affect the amount of light hitting your subject, but that’s for a whole other article.

Ok, I’m with you so far, but what about shooting ambient light?

If we’re shooting ambient light, and we are unable to use flashes or continuous lights to augment the light that’s available, we are at the mercy of what is around us or our subject. So, how do we add or remove stops of light in this instance?

Well, there are essentially three ways common to most all cameras out there. There’s the ISO (or ASA as it was often referred to in the film days), shutter speed, and your aperture. All of these methods of adding or subtracting a stop of light are a doubling of halving of the light that’s recorded.

ISO is the simplest to get to grips with. If we want twice as much light, we simply double the number of the ISO. If we want half as much light, we half the ISO. So, if we’re shooting at ISO400 and we want an extra stop, we switch to ISO800. If we’re at ISO400 and we want to lose a stop of light we switch to ISO200.

ISO/ASA on film was a physical property of the makeup of the film and its coatings. In the digital world, ISO is essentially just a different way for the camera to interpret the light hitting the sensor in order to give the appearance of more or less light. Every DSLR has a “native” ISO, which varies from body to body, and all other ISOs the camera is capable of are essentially simulated, based off the readings at this native ISO.

Shutter speed is a little bit different as speeds are often rounded off in order to simplify the numbers (going from say, 1/8th of a second to 1/15th of a second instead of 1/16th).

If we have a base shutter speed of 1 second, and we want to add a stop of light, we simply double the duration the shutter is open, so we set our shutter speed to 2 seconds. If we want to lose a stop of light, we half the amount of time the shutter is open, and we set it to 1/2 a second.

If we’re have 1/250th as our base shutter speed and we want to add a stop of light, we go to 1/125th of a second.  If we want to lose a stop of light, we go to 1/500th.

Aperture is probably the most confusing to many, as the numbering system used doesn’t follow the typical doubling & halving rule (it sort of does, but not directly). Expand the box below for a full explanation of why the numbers are they way they are, why it makes sense and why the numbers also seem to go the wrong way.

Right, that was way too complicated, is there an easier way to understand this?

Here’s the short version. This is a set of numbers that you should learn and become familiar with.

f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32.

f/1.4 is our brightest setting in this list, and f/32 is our darkest setting. Not all lenses go as bright as f/1.4, and not all go as dark as f/32 (and some lenses go brighter than f/1.4 or darker than f/32).

Each of the numbers in that list is either a stop brighter than the number than it’s neighbour on the right, or a stop darker than its neighbour on the left.  If, for example, you’re at f/4 and you want to lose a stop of light, you go to f/5.6, if you want to lose two stops, you go to f/8. If you’re at f/4 and you want to increase the light by a stop, you open up to f/2.8, and if you want to increase it by two stops you go to f/2 (assuming you have a lens capable of it).

Your camera may show other numbers in between those, these are either 1/2 stop or 1/3rd stop increments.  For now, you don’t really need to worry about those, but if you understand what’s been said above, you’ll probably understand that too.

Cool, got it!  So, is there anything else that can affect the amount of light my camera sees or records?

Why, yes, there is.  How fortunate you asked!

Pretty much anything that you put in front of a lens or a light source will affect the amount of light that is ultimately received by your camera.  For the sake of consistent and predictable results, however, let’s have a look at neutral density, or ND filters (and please, no arguments on whether they technically are or aren’t classed as “filters”).

One thing you need to remember about ND filters is that they can only take light away, they cannot increase the amount of light put out by a light or seen through your lens.

Why might I want to use one of them then?

There are two common situations where you might wish to use an ND filter.  One is the ability to shoot long exposures, and the other is to allow you to shoot in very bright conditions with a wide aperture in order to get a shallow depth of field.  In either situation, without ND filters, your camera could be seeing far too much light and just result in a pure white image with everything blown out.

ND filters work on exactly the same principle as above.  If you put a 1 stop ND filter over your lens, your sensor sees 1/2 the amount of light through the lens.  If you use a 2 stop ND filter, it sees 1/4 of the light, a 3 stop ND is 1/8th of the light, a 4 stop ND is 1/16th and so on.  Commonly available commercial ND filters go all the way down to 10 stops, which is 1/1024th the amount of light – which would allow you to shoot long exposures at very small apertures even in the brightest sunlight.

If you are using flash, and you’re already at minimum power, ND gels will also cut your flash power by even more.  SB-900 speedlights go all the way down to 1/128th power, that’s a reduction of 7 stops below their maximum power output.  If you’re shooting macro and your flashes are very close to your subject, even lowest power might be too much.  A 1 stop ND gel over the end of your flash will essentially give you 1/256th power.  A 2 stop ND gel will bring you down to 1/512th power.  You add however much you need to prevent the flash from blowing out your subject.

 Anything else?

Yes.  As mentioned above, pretty much anything you put in front of your lens will affect the amount of light the camera sees.  This includes almost any filter you put in front of your lens, although things like UV filters reduce the light by such a small amount it’s not even worth mentioning, especially high end top quality UV filters.

Circular Polarising filters (CPL filters), on the other hand, can decrease the amount of light your camera sees by as much as 1-3 stops.  Typically, the more expensive and higher quality CPL you purchase, the amount of light lost is reduced.  Sometimes this is an advantage, sometimes it is not.

And there you have it.  As mentioned at the top of this rather long article, it’s a pretty straightforward principle that can look very confusing until you figure out exactly what it is, what affects it, and how.

Many of the things mentioned above deserve complete articles all on their own, and most of those things will be elaborated upon in future posts, so stay tuned!