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Occasional Contributor
Posts: 5
Registered: ‎06-13-2018

Focusing

6d mark 1
5d mark 3
I just recently bought a new 50mm 1.2. On my 6d I was able to get good focus after micro adjustment at -10. On my canon 5d mark 3 it’s still seems to be off at -20 and is not as sharp as the 6d. I used the spyder lens cal and a tripod make sure I am 25*50mm back (about 50inches) I also shot wide open at 1.2.
Thank you
Occasional Contributor
Posts: 5
Registered: ‎06-13-2018

Re: Focusing

Is this a lens problem or my 5d? Thank you
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Esteemed Contributor
Posts: 4,358
Registered: ‎06-25-2014

Re: Focusing


@cbarron30 wrote:
Is this a lens problem or my 5d? Thank you

If it's either, I suspect it's a lens problem. A MF deviation of 10 is pretty high. (The farthest I've had to go is 9.) And you're saying that on the other body it's worse.

 

But you have to keep in mind that the 50mm f/1.2 is a tricky lens with a very low DOF at maximum aperture. You may want to play around with it a bit more before you send it in. Are you able to get accurate focus manually?

Bob
Boston, Massachusetts USA
Occasional Contributor
Posts: 5
Registered: ‎06-13-2018

Re: Focusing

So ya on my 5d it’s way worse. 

The picture below is at 0 microadjustment

 

0 focus adjustment

Occasional Contributor
Posts: 5
Registered: ‎06-13-2018

Re: Focusing

 This is at -208D984F29-64B2-4AF0-921F-F9649406B5F7.jpeg

Occasional Contributor
Posts: 5
Registered: ‎06-13-2018

Re: Focusing

I haven’t really tried manual yet. I know DOF very low but I just feel like it’s not as sharp or on point with it’s autofocus as it should be. ( I know it’s not the sharpest lens either) thank you for your reply!
Respected Contributor
Posts: 1,847
Registered: ‎12-02-2012

Re: Focusing

Are you testing wide open at f/1.2 for the shallowest possible DOF?  There's an oddly large amount of the scale in focus in the second photo.  Nearly the whole ruler. 

 

Could be a fluke of the curved focal plane working in accidental combo with the out of whack focus, on the slanted scale, I suppose. 

Scott

Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites

Why do so many people say "FER-tographer"? Do they take "fertographs"?
Honored Contributor
Posts: 6,371
Registered: ‎08-13-2015

Re: Focusing


@cbarron30 wrote:
6d mark 1
5d mark 3
I just recently bought a new 50mm 1.2. On my 6d I was able to get good focus after micro adjustment at -10. On my canon 5d mark 3 it’s still seems to be off at -20 and is not as sharp as the 6d. I used the spyder lens cal and a tripod make sure I am 25*50mm back (about 50inches) I also shot wide open at 1.2.
Thank you

Making AFMA adjustments should be done with care.  It is much easier to make bad adjustments than correct ones.

 

I perform adjustments at 50x the focal length, and at minimum aperture.  You should use lighting that is similar to the conditions that you expect to encounter when you use the lens.  I am certain that bright streak of light, which appears to be coming from a window curtain is not helping matters.

 

If you have any filters on the lens, you should remove them for the AFMA testing.  

 

You should take several test shots and average the results.  Take a shot, and then defocus the lens.  Defocus the lens both in front and behind the target.  If your results do not show a consistent trend, like a consistent amount of back focus, then you could be introducing error in your measurements.

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