My Canon XTi autofocus beep and light don't work

If it is a dark scene and the camera cannot detected edges well the autofocus will either move around a lot or simply will not focus and thus wont expose. You will just have to manually focus or use the flash

Are you using this indoors, in low light perhaps? This would be the most common reason for this happening. The only way to get around that is to use a "faster" lens, such as f2.8 / f1.8 / f1.4 etc.

If not, try cleaning the lens and camea contacts with a plastic eraser, make sure no debris falls in the camera body (hold upside down for this).

This may not be the same as your issue, but our AF stopped working as well. I tried all the recommended fixes - removing the card and battery, recharging the latter, removing the lens and cleaning the contacts, etc. None of those things worked. However, I then switched to MF, requiring me to turn the barrel, and I realized it was stuck and just needed a little force to get unstuck. Might have been the humidity. Anyway, our problem was solved - AF was back to normal after that.

I dropped my camera and thought the autofocus broke. It turn out that it swithed from autofocus to manual focus. There's a switch on the lens. Check if that's your problem too.

in that case my tipp don't mess with it further, pack it in (the body ) and send it to canon for a repair see www.canon.com and cntact them about this isue ask what the cost will be and send the camera in by secured and insured parcel service like tnt (www.tnt.com) describe on paper what ypi have done so that a expensive technician knows where to look.

Hey shutterbug72,
According to the manufacturer the first thing you should try is cleaning the lens contacts with an eraser. If that doesn't work you could try removing the battery and reinserting it to reset the camera. It seems to me that if there was a compatibility issue going on you should have seen that from the start. As far as what lens you should buy both Tamron and Canon make very good lenses, but with Canon lenses you shouldn't ever have compatibility issues. I hope this helps!

Sincerely,
Allan
Go Ahead. Use Us.

Backfocus problems will be magnified when using wide aperture lens with shallow depth of field, nice lens btw. Camera's adjustments for manual and autofocus are inside mirror cage behind mirror, and you dont want to risk getting dust on sensor or damaging sensor. Qualified camera repair shop or sending to canon for adjustment would be my suggestion.

AI should be focusing. You really can't change many settings when you are shooting in auto mode. Is the lens in AF mode?

I'm sure you have long since returned from vacation!

Hope this helps!

If you're on a budget, the 50mm f/1.8 II is a great deal, $100ish, f/1.8 is great for low light.

If you have a bit more cash, the 50mm f/1.4 has better build quality (the 1.8 is all plastic) and much better autofocusing (its USM so its fast and quiet, as well as more reliable) and its also slightly sharper.

If you want a zoom, from canon theres the 17-55 f/2.8, which has image stabilizer and USM focusing.
Also, the 24-70mm f/2.8L, which has USM, and since its an L lens, fantastic optical quality. However, it will run you over a thousand most likely.

From sigma, theres several zoom options, the 28-70mm F2.8 EX DG, 24-70mm F2.8 EX DG MACRO, and 24-60mm F2.8 EX DG. All under $800 or so.

same issue here, but with 18-200mm. worked for 18 months fine.