I sometimes got this kind of result when shooting bigger white birds like this egret. I figure it happen in the following situation:


when shooting white egret with a darker background(say trees), I set auto focus with at least -1stop exposure compensation, AV priority and evaluative metering mode. usually you can get correct exposure of the bird but background will be underexposed.then the bird takes off to the sky, and you keep shooting the bird in flight, because the sky and the bird have similar brightness, with the -1stop compensation, the whole scene will be -1 stop underexposed like the picture you are showing. to avoid that, use manual exposure to lock the correct exposure.


please anybody, correct me if anything wrong.