Some people learn best when they start at the basics: This is a camera. Press this button to make it go ‘click’, and it takes a picture. Change the aperture to… etc. Me, I like to work the other way around – I learned a long time ago that photography – like computers, cars, etc – is interesting mostly for its results, rather than for its technology. Who cares if your camera can do 1/4,000 second or 1/12,000 second shutter times… Unless, of course, you need the faster shutter time to achieve something.

Learning by example, then, is the act of starting at the other end of the learning process: Find a photograph you like, or come up with a crazy idea, and then start stepping backwards: What do I need to do to create the photograph I have seen / imagined / come up with.

What’s the point?

Boats on Ha Long Bay in Vietnam. Taken with a Canon Digital IXUS at ISO 200, f/8 and 1/30 second exposure, at widest possible zoom

The interesting thing of learning by example is that there’s a pretty good chance you miss whole fields of photography. If ISO or lens length isn’t relevant to the shots you’re taking, you’ll never have to learn them… It’s kind of like mathematics: I could never wrap my head around calculus. Not because I don’t have the brain capacity (or, at least, I would like to think), but because I never saw the point. Just like I never saw the point of geometry, until someone managed to bring it to life by explaining how I could apply it to my life – suddenly, I had a need for a bit of knowledge, so I went out to acquire the necessary information and understanding, and was able to do the calculations I needed.

I’m a strong believer in doing the same thing with photography: If you don’t think you need something, well, you probably don’t. You’ll eventually find out that the techniques you’re using at the moment are limiting you – or making the things you’re trying to achieve more difficult – but that’ll be new motivation to learn something new again.

So, how do you do it?

My sister in Vietnam. Taken at ISO 100 with a 50mm f/1.4 prime lens stopped wide open, aperture mode. Shutter time was whatever the camera suggested. Slightly desaturated the RAW file to get a more timeless 'feel'

Well, it’s easy: Find a source of inspiration. Personally, I use all sorts of sources: Magazines are a great starting point (especially amateur photography magazines like Digital Camera Magazine or similar – also check out PhotoRadar). Flickr, of course, is a marvellous source as well. The problem with on-line, however, is the nature of computer screens. Call me old-fashioned, but I really prefer the high-resolution way of looking at photography: Prints, books, magazines, etc.

The other problem is that, even on Flickr, not that many photographers take you through their way of thinking, or their technique for getting the shot (I love the idea of the How I Took It group, but so far, only 22 photos have been posted, which seems like a huge shame). Luckily, you can often ask questions, and many are good enough to help you along, but that’s still not an ideal way of getting tucked in. (Of course, I’m also guilty of this, but if you find any photos in my photo stream which you’d like explained and deconstructed, I’d be more than happy to – leave a comment and I’ll dig out the info!)

Using books for inspiration

Photos that Inspire is one of the few books I'm aware of that goes into detail about the individual photos, with how, why, where and when they were taken - perfect to start learning

There are a lot of fantastic photography books out there, but many of them are by a single photographer – the problem with that is that they have only a limited number of styles, and most of them say nothing about how the photos were taken – you’re expected to enjoy them as art, rather than as part of a learning experience. As you get better, this is a sensible approach, but when you’re starting out, it can be mighty frustrating.

The best one I’ve found that does things a little differently is Photos that Inspire (Amazon US / Amazon UK) is in the same series as my macro book – the Photo Workshop series published by Wiley – and it’s a peach.

For one thing, it has a couple of my photos in there (which obviously makes it a much better book already) but the important bit is that it contains tons of photographs taken by professional photographers – who explain why and how the shots were taken. It’s like a small art gallery with a personal guide by each of the individual photographers – and a fantastic place to start learning, of course.

How do you learn?

So, that’s my take on it – How do you prefer to learn about photography? Where do you get your inspiration? There’s a comment box down there somewhere…

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To understand exposure in photographical terms, EV is probably the single most important number you will have to understand, to understand the theory behind the art of photography. This goes from your tiniest, least significant compact camera, to your cock-on-the-table style medium format camera with a digital back.

Non-technical

Let us imagine a value called TCE. This TCE (The Correct Exposure) does not exist, because you might for a variety of reasons want a different exposure than the TCE. But for the sake of argument, let’s assume TCE exists, and this is what you will want when you take a certain picture.

To get a correct exposure, you will want to have EXACTLY the right amount of light to capture your image. Not too much, and not too little.

So, what is it that might affect how much light comes to the film or imaging chip?

Shutter speed – Imagine a mug with a lid containing a mysterious source of light, and the room you stand in is covered in darkness. Shutter speed would be how long you open the lid.
Aperture – Same cup, same concept, but this time, how far you open the lid (if you open it a little – small aperture, i.e. high aperture numbers (for example f/22). If you open it all the way – large aperture – i.e. low aperture numbers (for example f/2.8)
These are the two basic ones. The last factor that comes into play is your film speed, or the light sensitivity of your surroundings while holding the cup if you will.

That’s all there is to it – these three factors combined allow you to manipulate the light in all kinds of ways (big depth of field through small apertures, freezing motion through fast shutter times, etc).

So, to get TCE, you will want to combine these three factors into JUST the correct way. Now, if you replace TCE with TCEV (The Correct Exposure Value), you understand what I have been on about.

EV is a number describing an exposure – any exposure – regardless of its “correctness”.

Technical

The definition of EV=0 is an exposure of 1 second at f/1 using ISO 100 film, or any equivalent thereof (2 seconds f/1.4, 4 seconds f/2.0 etc)

The technical definition of EV is 2^EV = LS/C.

EV = the exposure value – explained above
L = field (or zone) luminance –
C = Exposure Constant – This is a constant that depends on what unit you are using to express the luminance (L)If you use candelas/ft², it is 1.3. If you are using candelas/m²*, it is 12.5*. If you use apostilb, it is 3,98.
S = film speed following the ISO standard

*) some of you might know cd/m² as lux or lumens/m²,

This also means that 2^ev = A²/T

A = the f-stop number of the aperture
T = shutter time in seconds

Combining these two; EV = log2(A²/T) = log2(LS/C) – which is the only formula you are likely to need, if you want to understand the basics of mathematics behind photography.

So what is the EV number used for?

Ah. Well, the EV number is used internally in cameras – an EV number of 10, for example, would refer to all the combinations of shutter times and apertures that would give a given exposure using ISO 100 film. This is useful, because a camera only has to add one thing to this equation; A light measurement. A camera with a lookup table or an algorithm to calculate the correct EV is all set for using all the different combinations that are able to give you the exposure you want.

But why would I care, if the camera handles everything?

Because the camera doesn’t always get things right. You may also want to use alternative exposures for artistic reasons.

Most cameras have an EV compensation wheel/dial, allowing you to choose how much you want to over/underexpose an image. This is usually measured in +/- 2EV, 1/3 steps. This means that you can over- or underexpose an image by two whole EV steps (which, incidentally, would mean the same as two full f-stops either way), in steps of 1/3 EV.

I hope that made things a little clearer – if not, leave a comment, and I’ll see what I can do!

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