Canon 70D Autofocus Image Shifting

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AndyG1

Active member
I just received my Canon 70D today. When paired with the new Sigma 18-35mm Lens something strange is happening. This is my only AutoFocus lens so I cannot test it with a different lens.)

In video mode with "Auto" settings on the camera, if I pan from one object to another (using AutoFocus) the image will shift abruptly. It doesn't matter which of the three AutoFocus modes I select. It reminds me of the image shift you might occasionally get with an IS lens, but this lens obviously does not have stabilization and the shift is always abrupt and very jarring making the footage completely unusable.

Has anyone else experienced this? I'm wondering if this 70D body is defective or just user error of some sort?

When I put the camera in manual mode the abrupt shifting stops. I'm familiar with "focus breathing" but this is not "focus breathing". It is a quick jarring instantaneous shift when panning from one object to another.

Also the Sigma 18-35mm lens works perfectly on my Canon 60D.
 
I went to a friend's house and did further tests with the Canon EF 24-70mm F/2.8L II, Canon EF 100mm F/2.8L Macro IS and Canon EF 85mm F/1.2L II. The only lens from this group that blatantly showed the hiccup was the 85mm F/1.2L II.

If I take any normal video and remove 3 frames it simulates what's happening exactly so I think my 70D is skipping frames under specific conditions.

(I'm using a Sony 64GB 94/mb Sec SDXC Card, but I don't think the SD Card is related to this issue)
 
How does it function when manually focusing? You're not likely to do any important projects with the camera on auto anyway, right? Does manual give you smooth shifts without frame issues?
 
"How does it function when manually focusing?"

The problem was directly related to Autofocusing and does not happen when manually focusing. I returned the 70D and I'm awaiting a replacement.

"You're not likely to do any important projects with the camera on auto anyway, right? Does manual give you smooth shifts without frame issues?"

I'm buying a 70D to use in precisely those situations when using Autofocus and perhaps Auto Exposure would be beneficial - such as on an RC Helicopter or Steadicam or fast paced live event with continuous shots from indoors to outdoors or handing the camera off to an assistant to shoot B Roll or behind the scenes etc ...

Here's what I know.

The problem occurred if the 70D was set to any Autofocus Mode and if the top dial was set to any mode other than (M) such as A, P, Tv, Av etc ...

I mimicked the effect on normal footage by simply removing 3 frames of video so for some reason the camera is hiccuping and skipping frames.

I was using (2) 94mb/Sec Sony SDXC Cards, but regardless of cards, the hiccups could be seen on the LCD screen even before recording so it's not a recording issue.

I'll be interested in seeing if it happens on the replacement camera.

Side Note:

I use a Sigma 17-50mm F/2.8 O.S. lens on the Canon 60D. I like it better than the Canon EF-S 17-55mm F/2.8 because its stabilization is completely quiet and the Canon 17-55mm's stabilization sounds like a quiet swarm of locust. Also the Sigma 17-50mm is slightly brighter wide open than the Canon 17-55mm, not by much - perhaps 1/6 of a stop, but the Sigma 17-50mm is also slightly wider at the 17mm end.

That said, when I put the Sigma 17-50mm on the 70D and engaged Autofocus, the Sigma 17-50mm went wild - hunting quickly back and forth non-stop - and I mean NON-STOP - like a malfunctioning R2D2 - it was crazy. Not sure why because it has always worked fine on the 60D when Autofocusing for still photos.

Another point:

When Autofocusing with the Sigma 18-35mm lens and the new Rode (Red Rycote Mount) Videomic on top of the 70D you will slightly hear the lens Autofocusing. If you need to gather audio from a camera mounted mic I would look for solutions that raise the mic up even further from the camera.
 
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