Focusing problem while using 50mm 1.4 on 7D

[rj79in]

Hi,

I am having a weird problem with autofocus using the 50mm 1.4 on the 7D. Autofocus using the viewfinder is resulting in the images suffering from substantial blur. However, focusing at 10x using liveview is giving perfect focus.
 
I've tested considerably using a tripod and a cable release to eliminate any blur caused by camera shake but the problem remains as it is.

Any suggestions ...

[zachdluchs]

I've heard of focusing issues with the 50mm 1.4 where the autofocus quits or breaks. Have you tried a different lens on your 7D to ensure that it isn't the focusing system on your camera?

[rj79in]

Have tried other lenses and all are working fine. The 50mm is the only lens I am having trouble with

[DJL329]

Shooting with a fast (sub f/2.0) prime will give you a very shallow DOF, so your point of focus has to be precise.  Try stopping down (f/2.8-4.0) and see if it's still an issue.

[rj79in]

Shooting with a fast (sub f/2.0) prime will give you a very shallow DOF, so your point of focus has to be precise.  Try stopping down (f/2.8-4.0) and see if it's still an issue.

Will try that ... but still it begs the question, why perfect focus using LiveView and imperfect focus using the viewfinder

[Mt Spokane Photography]

Shooting with a fast (sub f/2.0) prime will give you a very shallow DOF, so your point of focus has to be precise.  Try stopping down (f/2.8-4.0) and see if it's still an issue.

Will try that ... but still it begs the question, why perfect focus using LiveView and imperfect focus using the viewfinder

Livefiew focus uses a contrast detect method, and will always be near perfect.  it is slow though.  The viewfinder uses phase detect which is very fast, but might need to be adjusted.  Use your 7D AFMA feature to tweak the phase detect AF.  If it cannot be corrected, send the lens (perhaps body too) to Canon for adjustment.

[jwong]

Shooting with a fast (sub f/2.0) prime will give you a very shallow DOF, so your point of focus has to be precise.  Try stopping down (f/2.8-4.0) and see if it's still an issue.

Will try that ... but still it begs the question, why perfect focus using LiveView and imperfect focus using the viewfinder

Could be bad AF parts within the lens.  LiveView AF uses contrast detection which is more body driven.  I had an issue with a lens that was blurry from f/1.4 to f/4 with phase-detection but was fine with LiveView as well.  Sent it to Canon last week; hopefully I'll find out soon what's wrong with the lens.

[neuroanatomist]

I'd try AF microadjusting the lens. Some suggestions in this tutorial, or check out Reikan FoCal software.

[rj79in]

Nothing is setting it right. After considerable testing and trying out the microadjust, I have packed up the lens and sent it to Canon. It looks like a lens issue rather than a body issue because all my other lenses are working fine.

[neuroanatomist]

Probably best.  The AF system on the 50/1.4 is not the most robust (it's micromotor USM and achieves full-time manual focusing via a clutch mechanism, the only lens like that in the lineup).

[EOBeav]

The AF on the 50mm f/1.4 is notoriously unreliable. I owned mine for two years before I figured it out. If your 7D has microadjusting, try using that, but understand that you will still have some stray focus issues from time to time. Depending on what you're shooting, the Live View mode is probably your best bet. I recently discovered that on my 5DmkII and am glad I did. I call this lens the Mae West of camera lenses. When it's good, it's really really good. But when it's bad...

With all of that said, I love using my 50mm f/1.4.