EOS T3i - Autofocus issue

[larryl9797]

Howdy gang... I am having an intermittent issue with a EOS T3i that I purchased for my wife.

This was a kit purchase that came along with 18-55mm IS II lens. 

It appears that the autofocus function works imtermittently on my camera. I still have 2 months left on warrantee, but I wanted to run this by the group. 

Upon startup the camera works just fine. The stepper motor autofocuses, the camera will snap off a few (or more) pictures. that I will hear the stepper motor do its thing, the viewfinder autofocus points will indicate and light up. The focus confirmaiton light will blink. The camera will make the two tone beep. the Camera will take the picture.  Now when things go bad, they really go bad for this camera.

If I change a scene where the camera will have to move the lense and re-autofocus. Th stepper motor will not turn, the viewfinder autofocus points will not light up and the focus confirmation light will just blink. If I press down the shutter button, nothing happens. I get no beep.

I did call Canon support and they suggested a low level format of the card. I did that however the problem still persists.

 just need a conformation that this is not normal behavior and was wondering if anyone else had this type of issue. Thanks much!!!:

[ebiggs1]

"If I change a scene where the camera will have to move the lense and re-autofocus."

What exactly does this mean?  The camera needs certain conditions for the focus to work well.  A blue sky, for instance, will be a problem and would be 'normal'.

[larryl9797]

A scene change would be, Taking pictures of brown cows over to the left - Camera performs fine. I see a green cow to my right. I turn to take the picture. The lighting is about the same. The camrea does not do anything and acts like the above. 

[ebiggs1 · Accepted solution]

OK than you need to start the normal process of eliminations.

Does the lens work on a different camera?

Does the camera work with a different lens?

Are the contacts between the lens and camera clean? Try denatured alcohol and a q-tip.

You have already set the camera back to factory defaults? It is not the memory card, BTW. The camera should work whether it has a card in it or not.

If these simple things are not successful a repair facility is probably next.

[larryl9797]

Agreed ! and thank you.. 

[larryl9797]

Sound diagnostic advice... however AF still was flaky after performing all self diagnosis. Sent in for repair while it was still under warrantee.