Focus Problem

[tabrandt]

I put my Canon 70-200 F2.8 on my 20D last night to shoot some shots and found that instead of working like normal the focus just kept going back and fourth rapidly, never actually coming into focus.

I tried other lenes and they worked fine and then tried the lens on my A2E and it did the same thing.

I guess I take in into the camera store today. 8-(

Any ideas on what could be wrong and how much I can expect to pay to get it fixed?

Thanks

[Pekka]

Yes it sounds like lens problem, if it happens same on all bodies. If it is on warranty then you pay nothing of course. Even if you do not have a warranty you may be able to talk them to get it fixed under warranty, as this is not due normal wear.

[robertwgross]

... on my 20D last night ...

If the light is very dim, the autofocus lens will hunt in and out and never get a lock. That is not a lens malfunction. That's just the way they are.

If you put some light onto the subject, or if you get the autofocus assist system to illuminate the subject, then it might work better.

---Bob Gross---

[tabrandt]

Thanks Bob,

Unfortunately, the light should have been plenty bright. I also tried again today outside in bright (well, as bright as it gets in Wisconsin during May).

I dropped it off at the Canon dealer over lunch. He had never seen it before and said that he would call me if it was over $200.00 and it should be back within 3 weeks. 8-(

Thanks.