Welcome back! – I hope you’re gaining something from this course and, if so, please let me know! Suggestions, criticism, and praise are all welcome.
I’ve been thinking a little about the previous post – and really that’s what this is all about – making me & you think about photography. On reflection, focus & composition are more linked than I had previously considered. Cartier-Bresson had it about right when he talked of “The decisive moment” (he didn’t actually say that – he said “To me, photography is the simultaneous recognition, in a fraction of a second, of the significance of an event as well as of a precise organization of forms which give that event its proper expression.” — Henri Cartier-Bresson)
This was later shortened to the much snappier “the decisive moment” which is from a quote made by a Cardinal Retz. I don’t know why the good Cardinal said it but I suspect it had nothing to do with photography. But it is true that the decisive moment must involve composition - the precise organisation of forms. So to capture, accurately, the decisive moment you must have all the other elements such as focus in place.
Now off we go with “My 3 most important photographs” or “why do I get grey snow photos?” I don’t get grey snow photos of course, and neither will you from now on.
I want you to set your camera to fully automatic – focus, exposure, white balance – the lot. Enjoy it for it ought to be the very last time that you use the dreaded “A” setting. Check that your camera chooses centre-weighted average or evaluative as its exposure model – don’t use spot or expanded spot for metering in this test.
Get 3 pieces of A4 card – one white, one mid-grey and one black. I use proper photo grey & white – the type used to establish the correct exposure & white balance but anything will do, providing it doesn’t have too many artificial whiteners in the white sheet, and the grey should be mid grey – 18% grey in photographic terms.
In the centre of one sheet, put a small brightly coloured flat object. I’ve used a postage stamp but, again, anything will do providing it isn’t too large – the background needs to predominate.
Fill your viewfinder with the background and focus on the coloured centre-piece and take a fully automatic photograph. Repeat for the other two backgrounds, keeping the lighting the same for all three.
You should end up with three images similar to those below which you should look at on your (calibrated? Well perhaps not, as yet) monitor.
You will find that the colours of the central object look dull and underexposed when photographed on the white background which will be less than a bright white itself, more of a light grey.
On the black background, the coloured central object will look washed out and over exposed and the background will not be a pure deep black (on-screen here there is not too much difference between the grey & the black images but, believe me, the black background was a pure, deep black).
On the grey background, both the central object and the background will look just as they should.
Your camera, whichever make & model, has far more computing power than the early space missions but it has a couple of drawbacks too:
It doesn’t know what you are photographing
It measures REFLECTED light, ie the light that is reflected from the image, to gauge the exposure
Its exposure meter is calibrated to around 18% grey (some people say it is actually 16% grey, but the difference is immaterial).
Once upon a time, when analogue cameras first had built-in exposure meters, the manufacturers decided that "18% grey" reflected about the same amount of light as did Caucasian skin, blue sky, green grass and similar colours, so if the exposure meter got the exposure correct for those colours then around 90% of photographers would get an acceptable exposure 90% of the time. The same is true today. An exposure meter calibrated to 18% grey will do for most subjects.
BUT – if you take a photo of a snow scene, the camera thinks all the white stuff is green grass, blue sky or whatever, which just has a LOT of light on it – so it reduces the exposure and you end up with underexposed, grey, snow. It can underexpose by as much as 2 full stops.
Similarly, it thinks the black background is 18% grey with very little light on it, so it increases the exposure, again by anything up to 2 stops. The result is that your photograph of a black dog or car are overexposed and look washed out.
The accidental photographer will probably just shrug their shoulders and accept the result because that’s what everyone’s photos on social media look like. But you know better now, and your camera is set to Manual or perhaps Av or Tv which lets you decide what exposure you need.
You can carry a small 18% grey card with you and check the exposure using that (you can also use it to set the white balance) providing the light on the card is the same as is on your subject, or use the palm of your hand at a pinch, with the same proviso.
I know that I said I would cover the hyperfocal distance in this post but I’m afraid that tempus has fugit-ed so that’s all for now – tune in again in two weeks