Konica 50/2 M-Hexanon Back Focus Adjustment

[das]

Hi! Unfortunately, I have discovered that my 50/2 M-Hexanon is among the units that do not have correct backfocus on a Leica M body (apparently, some from the Konica factory were correct and others were not). DAG Camera is not able to adjust it. Does anyone know a good shop in the USA that might be able to take the project on? It does not appear to be a difficult adjustment -- there is a glued-on ring behind the lens mount that needs to be positioned correctly and then reglued in the right spot. Thanks!

 

[Chriscrawfordphoto]

Did DAG tell you why he couldn't fix it? He's adjusted those in the past.

 

[zleica]

I had my Konica M/ltm lenses adjusted by DAG few years ago.

 

[das]

He said that he just couldn't get it right. I did not want to bother him too much about it because I know he is busy and the lens is obviously not an OEM Leica product.

 

[astrobuoy]

I had asked him several months ago to look at my 50/2 M-Hexanon for the same reason. He told me that it really depends on the individual lens––in some cases there's less glue used to secure the rear so that he can get at the shims and adjust it, and sometimes there's too much glue and it's just not possible (or at least he is nervous to damage the lens and erred on the safe side). It sounds like there was an inconsistent amount of glue used to keep the shims in place when they were made, which is unfortunate since it's a nice lens!

You could try calling the Camera Doctor in NYC? Or maybe email Youxin Ye?

 

[das]

Yeah for sure that glue was tough to get off! I ended up soaking the bottom of the lens in a shallow pool of acetone (nowhere near the rear element of the lens) and eventually got it off. Thanks for the suggestions!

I had asked him several months ago to look at my 50/2 M-Hexanon for the same reason. He told me that it really depends on the individual lens––in some cases there's less glue used to secure the rear so that he can get at the shims and adjust it, and sometimes there's too much glue and it's just not possible (or at least he is nervous to damage the lens and erred on the safe side). It sounds like there was an inconsistent amount of glue used to keep the shims in place when they were made, which is unfortunate since it's a nice lens!

You could try calling the Camera Doctor in NYC? Or maybe email Youxin Ye?

 

[astrobuoy]

Yeah for sure that glue was tough to get off! I ended up soaking the bottom of the lens in a shallow pool of acetone (nowhere near the rear element of the lens) and eventually got it off.

Was that before or after DAG took a look at it? I would've thought with the glue off he would have no issue calibrating the focus?

 

[das]

I was aware of the glue problem, and removed it before sending it. To me, it's not a big deal whether or not it could be done by DAG. His work has always been excellent. I just love the M Hex so much -- just want to get it back in action. 🙂

 

[KoNickon]

I guess I need to take mine off my Hexar RF and see how it focuses on my Leicas. Was this a random issue, or is there only a specific serial number range involved? (I'm a little surprised that Konica used glue in this lens, actually.)

 

[astrosecret]

anyway to shim the lens or mount to get it to work

 

[das]

From what I can tell from looking into this issue over the years, it appears that maybe early M Hexs were not in precise Leica spec -- as the Hexar RF perhaps calculated film curvature differently than Leica. At some point later, the M Hexs shipped in precise Leica spec. That explains why some M Hexs are spot on and others need adjusting. Mine was definitely front focusing at f/2 at close distances.

I guess I need to take mine off my Hexar RF and see how it focuses on my Leicas. Was this a random issue, or is there only a specific serial number range involved? (I'm a little surprised that Konica used glue in this lens, actually.)