Lately I've seen a lot of confusion on here about exposure compensation in relation to bird photography. I will refer to this as EC from now on. Hopefully this thread will straighten out some things. I'm going to make this a really simple thread.
First I use evaluative metering which basically averages the whole scene and makes it look like 18% gray in black and white. The following examples assume EVALUATIVE metering is used. Although you can shoot in raw and fix exposure problems to some degree you will get a much better photo if your exposure is correct in camera. For example a lot of noise will result if you underexpose a image and later boost exposure in photoshop.
18% gray looks like this (this may look dark on a monitor but it's close). So your camera's meter is trying to make your photos average the gray patch below. If your photo AVERAGES lighter than this then the camera will Underexpose the image. If the photo AVERAGES darker than this and especially if your subject is white the camera will overexpose your subject.
Now here is a example pic with it's B&W counterpart
And here is what the meter sees in B&W
^As you can see in the photos above the photo 'averages' to lighter than the 18% gray so the camera tries to darken it (underexpose). So in this case for a situation where the photo is lighter than 18% gray you need to add EC to expose this properly. In these cases EC of +2/3 to + 2 are in order. In this example +1 was used although the correct EC was + 2/3 probably because of that dark stripe on top.
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^OK in this example we see the photo is much darker and averages to darker than 18% gray. Not setting EC here will cause the camera to overexpose the photo and burn the whites on the Stork. So in this case mainly when part of your subject has white on it you will need to adjust EC negative. The darker the photo average the more negative you need to go. -1/3 to -1 1/3 usually get it. In the example above -2/3 was the ticket.
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^Here is a common Bird in Flight Setting against a very light gray sky. In this case as in in case #1 above the meter will underexpose. Generally for birds in flight against a bright sky I set EC to #1 and adjust from there. In this case + 2/3 worked well mainly because the large group of birds darkened the average. If it was only 1 bird in this frame + 1 1/3 may have been better.
That's all the time I have to type tonight. I hope this helps some who are confused. I know this leaves A LOT of info out but maybe it's a start.
As said above this example assumes evaluative metering is used. If you are using spot or center weighted average then you can still apply these principals below but must do so using only the area of the viewfinder that the camera is metering.
