hello everyone,
just wanted to see if anyone else has had this problem. i suspect it is a mechanical problem that i need to send to canon to be fixed, but just want to check in with you all before i send it in to get an estimate on the repair cost since i'm out of warranty...

basically, when using autofocus my camera all of sudden will go from nicely focused to suddenly completely losing focus, even when the main subject in frame has not moved, neither has the camera. I'm not even talking about moving images - filming one person, MS, talking while sitting down; the camera just completely lost focus multiple times, and auto focus couldn't recover focus so I had to switch to manual. The lighting was a relatively well-lit room at night time. Then the problem recurred when shooting night time street scenes (which is less surprising). I've heard about wobbly autofocus in low light scenarios, so I'm just wondering if this is that type of thing, or if this is a mechanical problem. Does anyone have experience with this kind of problem? would appreciate any thoughts. thanks!

Not sure if this will help, but if you have a protective filter on your lens, sometimes stray reflections on it (like from passing cars, etc) might throw the autofocus off as it is constantly searching for what to focus on. This has happened to me a couple of times when the camera is on face detect or regular autofocus. I usually just switch the camera to manual once the AF has locked on to my subject.

Hi Todd,
Thanks - that's a good thought. I do have a protective filter on the camera... I've had it on there for much longer than I've had the problem but I'll take it off and see if the problem persists. Thanks!

I have an XA10 with a protective filter on it and have not experienced the issue you describe. I do not think the autofocus on the XA10 is as good as the focus on my older Sony V1U's but it does ok and certainly has not done anything strange.

Out of curiosity have you tried different focus settings? For example do you have face recognition on or off?

Aya, mine does the same thing, I think the focus drifts, do not know why. Especially bad in 24p, but it does it in 1080i as well. I have a habit now of going to manual focus. In low light the problem is particularly bad.

The auto focus on my XA-10s is not good and am hoping it's improved on the XA-20.

Page 53 of the manual discusses some of the limiting issues with auto focus. 24p is probably the worst case and 60i probably the best shooting mode. Also scene content, lighting levels, and aperture can come into play. Polarizing filters have been known to cause issues for some camcorders (not sure about the '10).

Well, Don, the manual, as you quote it, matches my experience, so I know now it was not in my imagination. I'm trying to get away from 24p for this very reason, focusing is more difficult in run and gun situations. 60i looks fine, is sharp, and less stress. 24p is fine sometimes, but the downsides are not worth it to me. I would rather have an image in focus than to have it in 24p and not be sure. Weddings are stressful enough already.

In a staged, tightly scripted shoot you can control camera angles, movement of the talent, follow action, and so on to minimize the motion artifacts of low frame rates. For live events with real people doing their thing (not a director's) 60i gives smoother motion.

After all, this is video, not film, for many if not most users. If one insists on using 24p where it does not fit well, live with the artifacts.

I'm thinking with the XA20 and its 60p frame rate that the issue should be reduced further.

For run and gun.

ian

Some folks love 24P for the film look. They like to see the stage coach wheels spinning backwards during the chase scenes.