5D mark iii auto focus issue, not the usual ones

[chriserben]

Hello,

This is what I am hoping is a setting issue, I have however tried just about everything and read everything I can find out there and have not found a solution. The AF seems to work in live mode. The AF in ANY other mode tries to work but does not focus on any target, just goes through the cycle of trying to locate a target then stop, from one end of the spectrum to the other no focus no beep. I have tried every AF mode I can find. It seems the AF mechanisms are working but it just can not see. I have reset all functions and settings multiple times. Anyone? Thanks folks!

[jrhoffman75]

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@chriserben wrote:

Hello,

This is what I am hoping is a setting issue, I have however tried just about everything and read everything I can find out there and have not found a solution. The AF seems to work in live mode. The AF in ANY other mode tries to work but does not focus on any target, just goes through the cycle of trying to locate a target then stop, from one end of the spectrum to the other no focus no beep. I have tried every AF mode I can find. It seems the AF mechanisms are working but it just can not see. I have reset all functions and settings multiple times. Anyone? Thanks folks!

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Welcome to the forum. 

That problem is frequently caused by an inadvertent setting. You stated you reset all camera settings and custom functions. 

A possibility is some foreign material like sensor dust on the AF sensor. 

https://community.usa.canon.com/t5/EOS/Auto-focus-stopped-working/td-p/152170  

Set the camera in manual sensor cleaning mode, to lift mirror, and carefully use a squeeze blower to blow off the AF sensor at the bottom of the mirror box. 

[chriserben]

yes sir tried that. Thanks

[chriserben]

Yes this was done. Thanks

[Waddizzle]

What lens are you using?  Does the camera have sufficient light and contrast for the AF system to function?

[chriserben]

I have tried many lenses in all light conditions.

[kvbarkley]

It sounds like the AF chip in the mirror box is bad.

[chriserben]

This could be a possibility, is this something that can be replaced? I have opened cameras and changed LCDs and a controller joystick, or is this terminal? Thanks

[kvbarkley]

I suppose it can be replaced, it is the alignment that is hard.