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Occasional Contributor
Posts: 5
Registered: ‎12-20-2018

6D autofocus suddenly can't find focus

Really hoping someone can help me out with this before I resort to sending it to Canon.

 

I had to leave my 6D sitting in it's bag for about a year locked inside of a safe. I had a half dozen dessicant packets in there and nothing else but some paper documents. I was however, ignorant enough to leave the battery in the camera for all that time. That may or may not be relevant. 

 

I just pulled the camera out and turned it on to find that the AF acts like what I can only describe as "bouncy." Focusing through the optical viewfinder, it will almost find it's focus point, then hesitate, then start bouncing back and forth rapidly between focusing just barely too far and just barely too close. It will do this infinitely until it finally just gives up, giving me the sign that it failed to find it's focus point. 

 

I have tried autofocusing using the live view mode (on the LCD screen) and it worked just fine, so I know it is not a lens issue and is likely originating from the sensor underneath the mirror in the camera body, as the AF used in live view mode does not use the same sensor that AF through the optical viewfinder does. I have blown the sensor area out with an air syringe to clear any dust. There are no signs of mold or corrosion anywhere. Used multiple different batteries all with full charge and life. Tried focusing in every different kind of lightning and every different texture surface.

 

My autofocus has always been lightning fast even in extremely low light in the past, and I'm stumped and don't want to pay Canon $300+ to diagnose and fix it if I don't have to. 

 

Any input would be much appreciated. Thank you!

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Valued Contributor
Posts: 443
Registered: ‎10-21-2016

Re: 6D autofocus suddenly can't find focus

Try resetting the camera to factory defaults, if that doesn't work remove the battery, lens and memory card,turn the camera on and hold the shutter button down for 1 minute. This should reset everything, refit battery, if everything has reset then you should be asked to set the date on the camera, refit lens and card then try the focus again.

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Posts: 9,252
Registered: ‎08-13-2015

Re: 6D autofocus suddenly can't find focus

Focus hunting can mean insufficient ambient light, or insufficient contrast on the subject. For example,the camera may not focus in a dark room. Or, it may not focus on a clear blue sky.
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"Doctor told me to get out and walk, so I bought a Canon."
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Occasional Contributor
Posts: 5
Registered: ‎12-20-2018

Re: 6D autofocus suddenly can't find focus

[ Edited ]

I have reset to factory defaults and all custom functions (although none of them should have affected this), but didn't know about that second method of doing it. I'll try that! Thanks

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Occasional Contributor
Posts: 5
Registered: ‎12-20-2018

Re: 6D autofocus suddenly can't find focus


@Waddizzle wrote:
Focus hunting can mean insufficient ambient light, or insufficient contrast on the subject. For example,the camera may not focus in a dark room. Or, it may not focus on a clear blue sky.

@dallaskye wrote:

Tried focusing in every different kind of lightning and every different texture surface.

 

My autofocus has always been lightning fast even in extremely low light in the past



 

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Honored Contributor
Posts: 6,415
Registered: ‎11-13-2012

Re: 6D autofocus suddenly can't find focus

It works correctly in Live View.

 

When its not working properly in "normal" view is it under the same conditions?

 

If so, then the problem would seem to tied to the AF subsystem. 

 

You could try going into manual sensor cleaning and carefully blowing some are down into the chamber where the AF sensor is to try and get any dust off it.

 

https://photography-on-the.net/forum/showthread.php?t=1019776

John Hoffman
Conway, NH

1D X, Rebel T5i, Many lenses, Pixma PRO-100, MX472, LR Classic
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Posts: 9,252
Registered: ‎08-13-2015

Re: 6D autofocus suddenly can't find focus


@dallaskye wrote:

I have reset to factory defaults and all custom functions (although none of them should have affected this), but didn't know about that second method of doing it. I'll try that! Thanks


Well, it definitely sounds like an issue with the body.  Get it checked out by Canon.  You could have a bad AF Sensor, or even a problem with the mirror.

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"Doctor told me to get out and walk, so I bought a Canon."
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Occasional Contributor
Posts: 5
Registered: ‎12-20-2018

Re: 6D autofocus suddenly can't find focus

Hoffman,

 

Thanks, but as I said in the post I already tried blowing air into it.

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Honored Contributor
Posts: 6,415
Registered: ‎11-13-2012

Re: 6D autofocus suddenly can't find focus

[ Edited ]

It wasn’t clear that you got down into the AF sensor area. If you did then you need service. 

John Hoffman
Conway, NH

1D X, Rebel T5i, Many lenses, Pixma PRO-100, MX472, LR Classic
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Reputable Contributor
Posts: 864
Registered: ‎01-25-2018

Re: 6D autofocus suddenly can't find focus

[ Edited ]

It isn't likely but not all desiccant packs are created equally.  I recall reading a note in an industry journal about the problems experienced by an electronics manufacturer because the porous plastic packs containing the desiccant were out-gassing plasticizers resulting in a film of pollutants forming on the supposedly protected equipment.  This is the primary cause of the film you see building up on the interior glass and mirrors of new vehicles and it probably isn't great for our lungs either.

 

If something like that happened, blowing air isn't sufficient and it will need to go to service for a proper cleaning.

 

Rodger

EOS 1DX M3, 1DX M2, 1DX, 5DS R, 1D M2, EOS 650 (film), many lenses, XF400 video
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