Help with 70D autofocus issue

Sep 8, 2019
7
1
Hi everyone, so I've been shooting since the days of the 10D and for the life of me, I can't figure out what's going on with the 70D I'm using. I'm between gear at the moment so I'm using my newspaper's body. Basically, it continuously focuses on the background instead of the foreground subject which I have the focus point on.

At least 70% of the time it does this. I've played with the custom function settings, wiped them all, etc. The lens has been serviced recently by Canon and it checked out fine so I'm ruling that out. The focus is also sluggish.

Is there something I'm missing? Some setting I've overlooked? If not, I might have the company send the body in for service. I've attached a few sample shots so you can see the issue clearly.

Please and thanks,
Dan
 

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privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
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It would probably help if you ran through what settings you are using along with the lens etc, are you using single point, zone, 19 point auto, etc etc.
 
Sep 8, 2019
7
1
It would probably help if you ran through what settings you are using along with the lens etc, are you using single point, zone, 19 point auto, etc etc.
I'm using a 70-200L 2.8 with single point auto focus in AI Servo continuous burst. Other settings, like custom function, I've tried them all.
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
15,696
874
Calibrating AF for front or back focus would not fix that first photo where its focused ~20 ft or more behind the subject. Either you did not have the AF point on the subject, or something is wrong in the AF system. The AF sensor sometimes gets dust on it, or even gets dislocated. Its located in the bottom of the mirror box behind the mirror. When its dirty or dislocated, AF can be wonky.

The main mirror has a half silvered area with lens and submirror below it to focus on the AF sensor. Its complex and can need cleaning or service.

You can verify AF better by testing it in a controlled manner. Put the camera on a tripod, focus on a subject with strong contrast and see if it focuses accurately. Compare live View Live AF with phase detect AF. Live AF should be right on, a problem points to a lens issue.

If it has a issue focusing with multiple lenses, send the body in for a repair.

 
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Valvebounce

EOS 5D SR
Apr 3, 2013
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Hi Dan.
Have a look at the images with software (Canon DPP) that can show the AF point locations, it may be that they are not where the viewfinder overlay says they were when you took the shot, a sign that someone else using the pool camera (pool camera = a device with very sketchy history!!) has dropped it or banged it hard enough to move the AF sensor.

Cheers, Graham.