Canon R5 focusing problems with Sigma Art EF-lenses.

[pipercarter]

I’m Having problems focusing with Sigma 24-70mm & 18-35mm on Canon R5 with either adapter. Can anyone help? I’ve purchased both adapters because I thought maybe the original one didn’t work but the control ring doesn’t work either. Or it could be my settings. I’m nit sure why my EF lenses won’t focus.

[Waddizzle]

What type of focusing problems?  No autofocus?  Soft Images?

Are you using a Canon adapter?  Are you experiences "focusing problems" with your Canon lens(es)?

You might have a perfect storm of camera settings.  Try resetting the camera back to factory defaults.

[kvbarkley · Accepted solution]

Have you contacted Sigma? You might need a lens firmware update.

[Tronhard]

First of all, the most detail you can give about what lenses are impacted (Sigma alone or native Canon EF as well - it was not clear to me).

Then, exactly what happens when these problems occur?

Did they ever work with the Canon R5?

Are the adapters native Canon ones or third-party?

Have you changed any settings from default in your R5 body - if so, I suggest returning the camera back to factory default and trying the lenses again

Do you still have a EF body and if so do the lenses behave correctly on it?

FWIW, I have the R6, which should be much the same and use Sigma 150-600c and 60-600s lenses without issues.

[pipercarter]

I’m using a Canon control ring with a Sigma 18mm-35mm lens.on autofocus the camera focuses on the side not the center.

[pipercarter]

I’m using a Canon control ring with a Sigma 18mm-35mm lens.on autofocus the camera focuses on the side not the center. The camera is on default settings from the factory.

[Tronhard]

My suggetion would be to try to confirm the source.

If you can try the lens on another body and see if that continues to be an issue it will tell you if the fault is with the lens

If not, then logic would suggest their is an issue with the adapter or camera

If you test the camera and adapter combination with another lens it should help you include or eliminate that.  I would think it unlikely that the camera body itself is at fault - it sounds more like an optics issue to me, but it deserves some further investigation.

In either case you will need to assure yourself that the camera centre line is exactly perpendicular to the plane of the test subject.

cheers: Trevor

[Waddizzle]

Maybe the camera needs to be in crop mode.  I believe the Sigma 18-35mm is designed for APS-C bodies.  I would doubt if the Sigma lens is automatically recognized as an EF-S mount lens, which would cause the camera to enter crop mode automatically.

[Tronhard]

Waddizzle appears to be correct! I just looked up the specs for the lens and it is designed for crop sensor bodies. That means that there will likely be very poor optics in extreme edges where the image delivered by the lens would not be captured by the crop sensor, and of course there will likely be some serious vignetting.

Do the images show significant vignetting? If so, it would make me suspect that the sensor is not auto cropping the image from 45MP to 17MP and is capturing an angle of view the lens was never meant to deliver.

If you check your manual on P143 and 900 it addresses these issues. You can confirm that the camera is working in crop mode, and, if not, set it as such - then re-test.

[Waddizzle]

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@Tronhard wrote:

Do the images show significant vignetting? If so, it would make me suspect that the sensor is not auto cropping the image from 45MP to 17MP and is capturing an angle of view the lens was never meant to deliver.

If you check your manual on P143 and 900 it addresses these issues. You can confirm that the camera is working in crop mode, and, if not, set it as such - then re-test.

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I am not aware of any third party manufacturers that use the actual EF-S mount, when having the EF mount works just as well on all Canon bodies.  So, I would not expect the camera to automatically switch to a 1.6 crop.