Sunny 11 explained

Today is going to be a busy day, I have an interview this afternoon for my gimp/code monkey so probably won't have time to blander with intent. So I decided to blip my today - a victim's CV.

Yesterday's blip I hinted at talking about exposure for digital, or Sunny 11 as I call it.

I wrote in a previous blip about the sunny 16 rule which is about manually setting your exposure based upon the sensitivity of your film setting your shutter speed, and your aperture.

All good and well, and you've probably noticed that I mentioned film, the 'sunny 16' rule is spot on for film - however digital is a different beast. Using it will give you a slightly darker shot (probably close to 2/3 of a stop).

There used to be an old trick where you overexposed and under developed to give a beautiful tonal range to negatives with lush shadow detail - and this is what we should be doing with digital. If we under expose the shadows can become very noisy when we process the shot, perhaps when trying to lighten them.

This works if we are shooting RAW. (JPG does processing in camera and so you can't 'really' do what I'm about to explain.)

RAW files are the digital equivalent of film negatives. They are the raw, unprocessed sensor data from your camera and they hold far more data than a JPG, in fact they hold about five stops of data from where you expose (two over, two under).

All good? excellent.

But. that's not the whole story. A camera sensor captures far more data in the light, and highlight quarters of the histogram than in the dark and shadow areas. this article explains it better than I ever could expose to the right.

In brief, the trick is to expose the shot so that the histogram curve shifts most of the data to the right (in the Highlight and Light areas) - the shot on your camera screen will look washed out however once you are back home you will be able to get the shot you want in camera RAW (or whatever RAW processing tool you use). this shot is before and after
, and here is the histogram straight from the camera.


In practice, I find that rather than sunny 16, sunny 11 works better in ensuring that I capture as much data as possible. It is a rule of thumb, but it allows me to have far more data to play with when I come to 'develop' the shot.