Konica M-Hexanon 50mm back focus on M9p

[FTI]

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Is there a definitive solution for the back focus issue with the 50mm m-hexanon lens on the Leica? I've read some posts about removing shims / or adding a shim. I've read posts from people who claim that the back focus is a hoax; because the version(s) they own(ed) or use(d) didn't display any back focus. I just recently picked up a copy and it's quite apparent on the M9p.  At closer distances the back focus seems negligible, but as soon as you try to focus beyond 2 meters (6.5 feet), it's quite bad. 

I really like the rendering of this lens, so I'm willing to consider possible fixes. I'd feel comfortable enough to removing the cam and doing something with the shims myself, but I'd lie to know what....  

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[ocean2059]

Few years ago, two of the Konica m-Hexanon lenses (50/1.2 and 90/2.8) had back focus issues. I sent both to DAG for adjustment and they have worked properly ever since.  

[a.noctilux]

FTI, at what aperture you used the M-Hexanon ?

I have one since decades which worked nicely on film M and Hexar RF, but some curvature of field and spherical aberrations make this lens "hard" to use on digital.

I investigated with M10/M246 with EVF to understand this "flaws" of this nice lens.

My conclusion is my M-Hexanon 2/50 is well adjusted at F/2 at any distance, but when used at F/2.8 or worse F/4 with rangefinder/EVF discrepency.

This lens has some "flaws" in certain situations to learn how to use it.

...

With my other M-Hexanon lenses 2/35mm and 2.8/28mm not such things to complain, they are spot on and as nice as can be.

[FTI]

6 hours ago, a.noctilux said:

FTI, at what aperture you used the M-Hexanon ?

I have one since decades which worked nicely on film M and Hexar RF, but some curvature of field and spherical aberrations make this lens "hard" to use on digital.

I investigated with M10/M246 with EVF to understand this "flaws" of this nice lens.

My conclusion is my M-Hexanon 2/50 is well adjusted at F/2 at any distance, but when used at F/2.8 or worse F/4 with rangefinder/EVF discrepency.

This lens has some "flaws" in certain situations to learn how to use it.

...

With my other M-Hexanon lenses 2/35mm and 2.8/28mm not such things to complain, they are spot on and as nice as can be.

Thanks for your feedback.

Backfocus seems to happen at all apertures; I guess dof eventually catches up and it becomes more tolerable. Only at close focus does the backfocus seem limited. I'm willing to learn to live with its discrepancy if not for the fact that I am looking for a main 50mm. I wonder if I should send it off for calibration. Although I don't eschew a bit of diy. 

 

[a.noctilux]

If your camera is RF calibrated, the lens may be faulty.

I can't help you more for lens calibration.

 

In my use, when I use the M-Hexanon 2/50 at F/2.8 or F/4, after RF setting, I turn 1-2mm the focus ring to compensate the "shift" (if I remember to do so ! ) ,

that way I use this lens mostly full open or F/5.6 onward.

This is not the only lens that has some flaws, I have many more ( ...some from 1930's ) to learn to live with pleasure.

[ocean2059]

I was told by DAG that the focus tolerance of M-Hexanon lenses developed for Haxar RF camera is slightly deferent that that of Leica M lenses for M bodies. I firmly believe that a recalibration adjustment will solve your problem.

[lct]

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On 4/11/2020 at 10:58 PM, FTI said:

I've read posts from people who claim that the back focus is a hoax; because the version(s) they own(ed) or use(d) didn't display any back focus. I just recently picked up a copy and it's quite apparent on the M9p.  At closer distances the back focus seems negligible, but as soon as you try to focus beyond 2 meters (6.5 feet), it's quite bad. 

Same here (32161**). Not a hoax at all. Very good lens otherwise. Works fine on mirrorless.

[FTI]

26 minutes ago, lct said:

Same here (32161**). Not a hoax at all. Very good lens otherwise. Works fine on mirrorless.

Thanks for the confirmation. Mine's 321116**** I really like this lens. Easy to use and nice rendering. Up close focus is okay, but it really gets bad beyond 2 meters. I'm going to check with Will van Manen in NL (www.kamera-service.info) to see what he says about it.

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[FTI]

OK folks. Had the lens serviced and it works great. Turns out that the lens needed to be recalibrated. There was some play and the rangefinder coupling of the lens needed to be readjusted. Lens had a CLA as well. Quick turn around and great service by Will van Manen in NL.

 

[ynp]

On 4/12/2020 at 8:45 PM, a.noctilux said:

In my use, when I use the M-Hexanon 2/50 at F/2.8 or F/4, after RF setting, I turn 1-2mm the focus ring to compensate the "shift" (if I remember to do so ! )

I have a back focus on my Konica 50/1.2 and I either compensate with the focus ring or just focus on the subject’s nose. 

I tried two of the Konica 50/1.2 and both had the same problem with rangefinder focusing. Unfortunately, I don’t know anybody who can adjust the lens in my part of the world ( Russia). 

[lct]

Will van Manen does it in the Netherlands if memory serves. You may wish to ask him if he works with Russia.
https://www.kamera-service.info/index.php/en/

 

[ynp]

37 minutes ago, lct said:

Will van Manen does it in the Netherlands if memory serves. You may wish to ask him if he works with Russia.
https://www.kamera-service.info/index.php/en/

 

Thank you very much 🙏