T5i Viewfinder Autofocus seems to be off

[clough42]

I recently purchased a Rebel t5i, and I'm having trouble with the viewfinder autofocus.  This is especially evident with a fast lens, like the EF 50mm f/1.4 I just bought for video work.

If I auto-focus through the viewfinder (phase detection) with a half-press on the shutter release, it locks focus quickly, but the resulting photo is very soft, and definitely blurry when magnified on the LCD.  If I put the camera in live view mode and touch the LCD (contrast) to take the photo, it's razor-sharp.

I am checking the focus with a high-contrast object, right at the focus point selected in the viewfinder (red dot).

I have tried some other (borrowed) lenses and get the same result:  EF 70-200 f/2.8L, EF 100mm f/2.8L macro, etc.

It makes no difference if I use support or get the shutter speed up to 1/250 or more.

Any ideas?  Should I return the camera?  Is this something that can be adjusted?

[ezpop · Accepted solution]

You seems to know how to test the focus of a camera.

Since you have tested with multiple lenses and in different modes, the possiblity of the problem is with the camera and not your 50 1.4. Return it if you can and bought another one. Otherwise, send it to Canon for warranty service.

[ebiggs1]

Are you sure the diopter is what is off in the view finder?  You may not be in focus after all if it is off.  You just think you are.

[clough42]

Sorry if my message wasn't clear.  I have adjusted the diopter, but I'm not judging the focus through the viewfinder, I'm using the quick phase sensor autofocus points in the viewfinder.  When I use the contrast autofocus, available ib live view, it works fine.

I have packaged the camera and lens up this morning and it's going to Canon.  They can sort it out.

Best Buy is no help at all.  I was kind of thinking that buying local was a positive thing, since they're the last surviving electronics store where I live.  I'm not so sure any more.

[clough42]

Canon sorted it out.  The lens required adjustment.  It's better now, but I'll probably not trust the quick focus wider than about f2.8.

[crbrown743]

My camera also started giving me AF issues when taking photos in viewfinder mode. AF works fine for subjects that are close-ish... My AF doesn't work on horizon shots at all. The lens goes to its closest focus setting and starts clicking and then doesn't work at all, which seems wierd, since it should be going to infinity. If I point at something closer it will focus and take a pic.

If I switch to live view it works. I've had the camera about 2 yrs and it just started happening. First with the standard Canon 18-55 lens and now with my Tamron 18-270. 

Guess it's time to send it back to Canon...