I was using my Canon 300D with a Tamron 28-75mm lense on the body and it just stopped taking pictures. It won't focus using the autofocus setting. I have changed camera modes, lenses, batteries, and CF cards and it just won't focus. However, when I put it on manual focus mode it will take pictures.

I am thinking something is wrong with the CMOS perhaps but I am not technical when it comes to the parts of a camera. Any ideas or suggestions would be appreciated!

:rolleyes:

You've tried other lenses, so I'd think it is the body.
Unless the electrical contact on the camera body is dirty (or damaged) and that's affecting it?

You want to be careful as there's good chance of getting dust into it :(
But when you remove the lens, at the bottom of the lens mount, in the camera just below the mirror, there are a set of gold-plated contacts.
Are any of them damaged, or dirty?

The AF circuit is seperate from the CMOS sensor and it has it's own processor. AF circuits go bad occasionally. Since it will focus in manual mode but not in auto it IS an AF issue in the body. It can be repaired, but you have to decide if it is worth it. You can call Canon and ask for a high/low figure to repair it.
As an example I had the same issue last year on my original 1D body. It cost $15 each way to send it in to Canon through the dealer and $248 to get it repaired. It took 8 weeks to get the body back because Canon had to order the parts. Te camera works fine now, although they returned it with finger prints and dirt on the mirror and IR filter. It had to be cleaned before I could even use it, although Canon did pay for the cleaning.
Anyway, it is an AF issue in the body, not with the lenses.

JS