Need Advice on Improving Autofocus Performance on My Canon Setup

[jaxonreed]

I’ve been experimenting with my Canon gear lately and wanted to get some insight from the community. Recently, I’ve noticed my autofocus accuracy fluctuating, especially in low light and fast-moving situations. I’m not sure if it’s a settings issue, lens calibration, or something I’m overlooking.

I’m mainly shooting portraits and occasional action shots, and while I’ve tried adjusting AF modes and tweaking settings like Servo AF and tracking sensitivity, the results still vary. Before I consider sending the gear in for service, I thought it would be best to ask the experts here.

Can anyone share tips, recommended AF settings, or common mistakes that might affect performance? Also, if calibration is needed, what’s the best method or tool to use?

Looking forward to hearing your suggestions and learning from your experience!

[SignifDigits]

To better support you could you please provide details of your Canon gear which you are using and what settings you are modifying?  Many camera bodies and lenses have specific performance characteristics, so it would, I think, be more useful to you if we were specific rather than generalizing, particularly in light of you considering sending gear in for service.

[ebiggs1]

"... especially in low light and fast-moving situations."

No matter what gear you have the main most important thing is contrast. The more the better so as light gets low so does contrast.

[stevet1]

jaxonreed,

You have raised two different scenarios. As ebiggs said, all cameras struggle with focus in low light. The best you can do is get as much light as you can and look for the areas of greatest contrast. Focus on the line where dark meets light.

With fast moving subjects, if they are moving in a straight line, you could try panning. Set your shutter speed from 1/60th to 1/125th of second and follow your subject along firing off a slow burst of shots. If the subjects are moving in an erratic fashion and you want to freeze the action, try using a zone and fire off a burst of shots.

Steve Thomas

[SignifDigits]

Thank you for posting. You are not alone in having low-light autofocus issues.

jrhoffman75 mentioned this reference https://www.canon.co.uk/pro/infobank/.  There is an article called "All About Autofocus" https://www.canon.co.uk/pro/infobank/autofocus/  - (I looked this over and want to read and understand this one myself).  One of the "Related Articles" at the bottom is "How Canon's Intelligent Autofocus System Works" at https://www.canon.co.uk/pro/stories/intelligent-autofocus-explained/ . At the bottom of that second article is a paragraph on "Focusing in Low Light". 

There is a LOT of good information in the articles, but there is also a fair amount of marketing and "wonderfulness" - enough to make us all want the eye focus of the R5 Mark ii, for sure.  But the first article has a lot of VERY useful "this is what the setting on your camera really means and does".   

Hopefully this helps you to ensure your settings are configured the way that you want them to.  The site doesn't have a lot of "darn it, sometimes things just don't work the way that I expected", which is what you came here for.  I think all of us have experienced that "darn it" moment in autofocus from time to time.  It definitely helps sometimes to get close wtih manual focus - especially when the camera supports focus pull with magnification or "manual focus zoom box".   I didn't explore every link there so don't consider my search exhaustive.

I hope that one of those sites might provide some useful settings.  In wondering about how to get the contrast ebiggs1 talks about, and a little research indicates that the following might be worth trying:

1) Start with the lens wide open to get as much light and contrast

2) Start with single point focus when you have the high contrast

3) Use Auto ISO and Focus Peaking

4) Use eye/face detection

5) (and this one is something I need to work on) Be prepared for the technology to fail you and use the manual focus ring enough to be ready and comfortable with it - especially if you want more depth of field than a wide-open lens gives you.

I have trouble with autofocus on the moon fairly often, haze around the moon almost always.  There are just some situations where no matter how good the autofocus technology gets our eyes and brains are just going to be better. 

There are some situations that I'm convinced cannot be captured by a camera because our brain processes them differently.  I have never seen a shot that truly captures the awesome beauty and wonder what I saw in the full solar eclipse in April 2024.  I doubt any film or camera sensor is capable of capturing anything but a single slice of the dozens of layers that our brain puts together in a situation like that.

[justadude]

This might be the ultimate YouTube video explaining Canon's auto focus.  I know we are not supposed to post outside links here, but this is with Canon's own legendary USA Technical Marketing Consultant, Rudy Winston... so I hope the group moderators let it slide by.  It's a long video, but there is a ton of information here.

 https://www.youtube.com/watch?v=eIxK8B-_Kn8 

[ercmicwil]

If you are using a DSLR you can perform a lens calibration on most Canon DSLR's. The calibration profile will be saved to each lens you perform this on. Sometimes this helps. Note that you cannot perform a lens calibration on mirrorless cameras because the calibration is intended to correct for subtle errors in the mirror alignment of a DSLR pentaprism. 

If you're using mirrorless, or if it's not a lens calibration issue, it's most likely a low light limitation of the camera/lens combo that you're using. If your shutter speed and stabilization was sufficient to eliminate any motion blur, you can sometimes salvage these low light images in post with a bit of adjustment to exposure, contrast, and sharpness.