Tuesday, June 07, 2016

Photographing Black on Black

I’ve just finished my colour theme daily photos, and finished off with a black image. I discovered largely black subjects (my camera gear) against a black background are hard to capture.  First issue is of course that black is not really a colour, it is what happens when all light (including all colours) is absorbed by the objects surface and no light (or Colour is reflected. Thus black is really the absence of colour, however expect intricate arguments on this question because a lot of folk have strong views.

#159_IGP5780_1_2_Why is all our gear so black?

Secondly taking a black on black photo with a modern digital camera Typical cameraphone exposureIs actually very difficult if you rely on the camera’s exposure selection. Basically your camera’s light meter is trying to make the resulting exposure a mid tone grey, with perhaps some white highlights and some areas of deep shadow being black. (see photo on right). It has kept the shutter open longer than necessary and many areas that should be black not appears grey. Our eyes do not have this problem, our brain knows it was black and will not try and make it grey, we just see black.

One way to compensate for this to use exposure compensation, to deliberately underexpose your photo when you are capturing the image. This is available on most digital camera but might require a bit of investigation. Look for a little +/- button(with an icon like that shown on right). The allows the camera to shift towards under exposing (increasing negative Cameraphone EV=-3numbers) EV iconor over expose (Increasing positive numbers). Normally this will be achieved using an EV (exposure value) which is a number to reference the amount of light reaching the sensor. Bu convention each unit increase in  EV represents a doubling on the light. (eg EV=1 is twice as much light as EV=0). For the image on the left I deliberately underexposed to EV=-3 (a 1/16 of the light compared with the image on the right above. This is much closer to what my eye sees. Some default phone camera apps may not allow EV compensations but may offer modes to achieve this eg night, snow etc. Also most DSLRs do not allow EV compensation in all modes, but you should be able to use it in P (programmed auto) Tv (shutter priority) Av (Aperture priority) and M (manual) modes.

A favourite shortcut of mine when I am not sure of the right amount of exposure compensation is to use bracketing, where the camera takes a series of exposure (usually 3) but varying the EV (offend 1 EV or 0.5 EV). Most DSLRs will let you set the number of exposure and the steps size. My camera lets be set the starting EV as well so In the series below I took EV=-1.5, EV=-0.5 & EV=+0.5.

Bracketed set of images

I ended up selecting the EV=-1.5 image, and being Raw photos I have more flexibly to alter the white balance and exposure in post processing, but I have only done some minor tonal tweaking.

One problem I have not solved in my photo at the top is related to light sources. There was natural light coming from a window behind the camera (on a very dull day) and I had an incandescant side light (and had to do a little white balance in post processing). But I should have used at least one white reflector just on shot to bring a little bit of sift backlighting to highlight the outer shape of the cameras. There is always time to learn

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