One of the characteristics of single lens reflex cameras is the mirror moves when you shoot, blocking out the viewfinder while the shutter is open recording your image. Just a fact of life. Another fact of life is that while the mirror is up, things are happening that you can't see. Usually bad things, people move, change expressions, the ball goes out of the frame. That kind of stuff.
Sometimes it is something good, thought. Last week I was shooting koi, those huge goldfish. The owner had fed them and they were coming to the surface to eat. I was banging away with my 70-200, shooting tight. What I was seeing looked good. Had one fish really big in the frame, with its face and mouth out of the water, others behind and underneath, enough out of focus to be a nice color element.(Sometimes I sound like I know what I am doing)
I came back to the office and started editing my images. I found quite a few with these huge bubbles. Do koi burp?
Several years ago I was out at Houston Lake photographing the alligators. Got a quick shot of one as he surfaced, then went back down. When I edited I found the shot with the turtle in his mouth.Sometimes you get these neat surprises.



