[NKWderek]

I reviewed many nice photos of flying bird here and found that most of
C hing used 光圈先決 to take this kind of photo. They are the moving
object. Why should we not use Tv mode? Can any C hing teach me?
Thanks.

[pongyee]

Before I guess an answer, can you tell me under what circumstances will you use aperture priority? And when will you use shutter priority?

Your answer will certainly solve your problem.

[tam_dominic]

My 350D focusing system is not that fast and accurate so I set F8 as much as possible to get larger depth of field.

Another reason is that shooting flying bird need long focal length lens and the depth of field is small so a fixed smaller aperture is desired.

Since I pan the flying birds, the shutter speed is less important but ISO400 is always used though.

Other C Hings may have their answers.