topic Re: 5D mark iii auto focus issue, not the usual ones in EOS DSLR & Mirrorless Cameras

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

chriserben — Sat, 30 Jan 2021 03:04:58 GMT

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!

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

jrhoffman75 — Sat, 30 Jan 2021 14:28:27 GMT

@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!

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.

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

Waddizzle — Sat, 30 Jan 2021 14:52:57 GMT

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

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

kvbarkley — Sat, 30 Jan 2021 15:36:31 GMT

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

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

chriserben — Sat, 30 Jan 2021 17:38:05 GMT

I have tried many lenses in all light conditions.

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

chriserben — Sat, 30 Jan 2021 17:44:48 GMT

yes sir tried that. Thanks

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

chriserben — Sat, 30 Jan 2021 17:48:25 GMT

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

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

chriserben — Sat, 30 Jan 2021 18:21:55 GMT

Yes this was done. Thanks

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

kvbarkley — Sat, 30 Jan 2021 20:10:47 GMT

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