80D focus problems???

[maykel_lazar]

G'day guys! As the title says.. am I having focus issues with my 80D?

Recently I purchased a canon 80d and sigma 18-35mm as my upgrade coming from a 700d. First thing I noticed was back focusing (further than intended focus point) using the sigma lens, minor at 35mm but ridiculous at 18mm. I did sort it out as much as I could with in camera micro adjustment. What I did find odd was even in live view shooting it was mis focusing with the sigma 18-35. At first I thought "oh never mind it's the lens" but then it got me thinking.. Live view should always be sharp no matter if the lens has focus issues. So I went ahead and mounted it to my 700d. As I expected, shooting using the view finder resulted in out of focus photographs however in live view the 700d had crystal clear shots. So why didn't my 80D have the same results using the live view mode? Is duel pixel AF off?? Can someone shed some light on this?

I will add that I have a 55-250 kit lens that I tried on the 80d.. results looked fine, both in viewfinder and live view mode..

Odd results!

 

[goodguy]

Seems like lens issue, go to Sigma and ask them to calibrate it.

 

[Derrel]

Must also keep in mind that an 18-35mm lens will have a wide angle of view, and the AF area boxes will cover a LOT of physical real estate, especially at distances beyond 10 feet to 15 feet...with a telephoto, the AF squares cover very small, discrete areas, and it is easy to aim them. With an 18mm lens, up to 35mm, those same AF squares can easily be slightly mis-aimed; if an AF square partiually overlaps a person's head, but the other half of the AF square can "see" a background item that has good contrast, or a pattern, the AF system will almost always go for the high-contrast target.

And as stated: this could also be a Sigma lens issue. Out-of-calibration lenses are not all that rare, and third-party lenses like Sigma, specifically, seem to be more prone to focusing issues than camera-maker-brand lenses. The fact is, the Live View cross-check you did makes it seem like this is, indeed, a Sigma-based lens issue. Good thinking on checking that out.

A possible issue--the dual-pixel AF technology is FAIRLY NEW...perhaps the lens has older firmware, and is not 100% compatible with that newer, Canon-developed protocol.? Third party lens-makers must reverse engineer their products to work with the cameras; the camera makers do NOT supply Sigma with full information on their AF protocols, and this 18-35 was developed not ONLY FOR Canon...it was developed to be a lens that could be used with other brands of cameras as well, so...I'd contact Sigma about the issue, or the dealer who sold the lens, and see what the course of action might be.

 

[maykel_lazar]

Must also keep in mind that an 18-35mm lens will have a wide angle of view, and the AF area boxes will cover a LOT of physical real estate, especially at distances beyond 10 feet to 15 feet...with a telephoto, the AF squares cover very small, discrete areas, and it is easy to aim them. With an 18mm lens, up to 35mm, those same AF squares can easily be slightly mis-aimed; if an AF square partiually overlaps a person's head, but the other half of the AF square can "see" a background item that has good contrast, or a pattern, the AF system will almost always go for the high-contrast target.

And as stated: this could also be a Sigma lens issue. Out-of-calibration lenses are not all that rare, and third-party lenses like Sigma, specifically, seem to be more prone to focusing issues than camera-maker-brand lenses. The fact is, the Live View cross-check you did makes it seem like this is, indeed, a Sigma-based lens issue. Good thinking on checking that out.

A possible issue--the dual-pixel AF technology is FAIRLY NEW...perhaps the lens has older firmware, and is not 100% compatible with that newer, Canon-developed protocol.? Third party lens-makers must reverse engineer their products to work with the cameras; the camera makers do NOT supply Sigma with full information on their AF protocols, and this 18-35 was developed not ONLY FOR Canon...it was developed to be a lens that could be used with other brands of cameras as well, so...I'd contact Sigma about the issue, or the dealer who sold the lens, and see what the course of action might be.

Sorry I forgot to mention I always use Af in manual one focus point and that being the centre one. I see your point with the overlapping issue but the test I conducted was controlled. I printed out a test sheet and pinned it to a wall then mounted the camera to a tripod and shot with a remote. I also always zoomed in X10, focused, and then took the shot. I could see straight away even before I took the shot that it was back focusing. Seems odd to do so right?

I just found it odd that in live view mode it would focus 100% perfect on the 700d and not on the 80d. That's why I have concerns.

 

[table1349]

This might help you determine the extent of the problem as well as providing a proper setup to do micro adjustments to the lens and see if that helps.

 

[maykel_lazar]

Seems like lens issue, go to Sigma and ask them to calibrate it.

Thanks mate, I have already. My problem is that I want to narrow down if there's a issue with the camera also, because if there is, the calibration sigma does will be pointless if I find out after the body needs calibration too.

 

[maykel_lazar]

This might help you determine the extent of the problem as well as providing a proper setup to do micro adjustments to the lens and see if that helps.

That won't do anything for liveview shooting, micro adjustment only affects view finder shooting. Which I have pretty much nailed when calibrating it. My only issue in live view. My 80d does not focus right but 700d does

 

[maykel_lazar]

Thanks for all your help guys! I've got to the bottom of it. It's the duel pixel phase detection that's causing the issue. 80D has this feature implemented in live view too not just via view finder. The 700D uses contrast detection in live view hence why it is focusing correctly.