Focusing tips for flying birds?

Forget auto focus and pre focus the lens. Planned shots are always better than random shot relying on the camera, it gets rid of the variables. The trick is to think about the shots you want, pre-plan them don't rely on doing it on the fly (pardon the pun) LOL.

In bird sanctuaries birds fly along a predetermined flight path, usually from the handler to a perch and back. Decide where you want to take your picture. Decide your angle keeping in mind where the light is coming from, one good shot to go for is from behind the perch as the bird is landing. Don't get too close to the perch, shots with the whole bird in with their expanded wings are usually best, leave yourself some 'wiggle' room, expect to have to crop your shots a little. They usually do it several times so you can try different apertures.

Pre-focus the lens at this point, 3 to 5 feet before the perch (have someone to stand there before the display starts, focus on them then turn auto focus off), select the aperture to give the depth of field you want. Pre-focusing the lens has the advantage that your camera will take the image(s) instantly.

As the bird approaches the perch take your shot(s), it's one of the few times I use continuous shooting then you will have a selection of images to choose from, all will be lit correctly as you've already worked out the birds angle to the Sun and will have plenty of detail, all will have action in them, a few of them will have just the bird in focus with a blurred background if you choose a wide aperture.

Pre-planning your shot(s) is the key to success. Birds traveling towards you are easier than trying to pan a shot.

Chris

Put your auto-focus in "AI Servo AF" mode for continuous focusing. Once you lock in on the bird, the camera will maintain focus. Select the AF mode that will allow the main subject to leave the main (selected) focus point and be tracked as it moves. I don't know what Canon calls it, but the Nikon term is "Dynamic Auto-focus." I usually choose the 9-point setting, as you can usually predict the direction birds are going to fly, but the 21- or even 51-point setting is helpful for birds that are darting around.

Set the "Drive mode" for continuous shooting. You decide on high speed or low speed, depending on what exactly the birds are doing. Don't just "take a video" of the bird, though. Shoot in short bursts of maybe 4-5-6 frames, as if you were taking a single shot. The odds of one of those frames being in focus and showing just the right wing position that you want will be greatly increased.

If you have a longer lens, you might consider using it. I use a D300, which has about the same crop factor as your 500D, and find that I use the 300mm end of the 28-300 (or 70-300) lens quite a bit. Some of these samples show birds; all are at 300mm: http://www.flickr.com/photos/samfeinstein/tags/300...