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Old Sep 13, 2005, 11:42 AM   #1
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I am having trouble getting my Canon EOS 20D to autofocus on a bird in flight. I have two lenses that I primarily use for birding, the 300 IS f4L and the 400 f5.6L. I usually am unable to locate the bird with the camera even if I manually set the distance first so the camera doesn't have to search so much first in trying to locate the bird. I can easily autofocus at stationary objects in the distance but am having problems with moving objects against a bright blue sky (includes a plane). I would appreciate any advice and will give more information upon request. Thanks!
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Old Sep 13, 2005, 12:00 PM   #2
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How big is the bird?

It depends on people/technique, but I use mostly single focus - I believe theses were sky shots: http://www.stevesforums.com/forums/v...mp;forum_id=11
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Old Sep 13, 2005, 12:07 PM   #3
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The birds I am trying to photograph in flight are big - Ospreys, Turkey Vultures, Eagles, etc. I would, of course, like to get the bird in focus and then continue shooting using AI Servo.
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Old Sep 13, 2005, 12:11 PM   #4
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AI servo rarely works for me: http://www.stevesforums.com/forums/v...mp;forum_id=11

The background get the attention instead (especially when it get busy) :?
I tend to set the exposure manually as well - because of the varying backgrounds... :idea:
(plus it does not work well on black or white birds)
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Old Sep 13, 2005, 12:17 PM   #5
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Shooting planes (with your 20D) you be no problem at all. Birds in flight require a lot more practice. If using AI sero mode, use center focus point and keep your subject in the center. I am assuming you have continuous shooting mode enabled. Acquire your target with half press of shutter button and while panning with it, press the shutter buton to take shots. You can also trying focussing with * button instead of the half press of shutter.

style="BACKGROUND-COLOR: #000000"Start with slow flying birds like gulls.
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Old Sep 13, 2005, 12:23 PM   #6
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It is not only size of bird it is also distance to bird that will affect AF.
Like NHL and others I find ai-servo is not so good, and ai-focus is almost a joke.

I tend to use one-shot or manual focus, and do tend to set exposure manually as well.

Your target needs to be large enough for the AF sensor to cover, which is not the same size as the AF focus mark in the viewfinder.
Also at F4 and F5.6 the camera is not using the high-precision feature of the center focus point.

Need Eric S to chime in here, he does get absolutely great results with his 600F4L.

Peter.
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Old Sep 13, 2005, 2:34 PM   #7
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Yeap - One-shot AF 1/750s f/8 @ 600mm:


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Old Sep 13, 2005, 4:54 PM   #8
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:roll:I had a lot of fun trying to shoot a bird in air and is not easy, I use mid focus point with shutter wide openat faster speed.

Use Rebel with 70-200f4.0:blah:
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Old Sep 13, 2005, 5:29 PM   #9
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I have my own 'theory' on this... sometime you don't want to use too fast of a shutter speed - This work well to convey the movement instead of freezing a bird in mid-air



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Old Sep 13, 2005, 6:15 PM   #10
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You are right NHL and picture look beautiful but a enthusiastic newbie still has a lot of practice to do,and a lot of things to learn.
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