Nokton 50/1.1 Back Focus

[Pioneer]

I have a very nice Nokton 50/1.1 that is back focusing quite badly on my Leica M9. It is the lens since I have others that do not exhibit this problem. On the LensAlign it is all the way back to the 20 on the scale. How do I go about having this lens calibrated, and will calibration make it work on my M6 as well or will that camera need to be calibrated with the lens as well?

 

[peterm1]

It is best to calibrate the lens and camera together.

 

[flash]

It is best to calibrate the lens and camera together.

I disagree with this. Modern cameras and lenses are calibrated to a standard, not to each other. Otherwise everytime you get a new body or lens the whole lot has to go off for another round of calibration.

The 50mm Nokton 1.1 has very fine tolerances for focus errors and also exhibits focus shift (noticable between 1.8 and f5.6 especially) so make sure you're doing you testing with the lens wide open. If it is indeed out and you are sure your camera is in spec then send the lens off. With my Nokton 1.1 it was the camera that was off, not the lens. ther lenses with smaller apertures didn't show the issue because DOF masked it. But I found out very fast when I got my 135 APO telyt that the rangefinder on my M9 was out.

gordon

 

[jaapv]

Flash is spot-on. Send your lens to a reputable repairperson: DAG, Will van Manen or any other that knows his rangefinders and have it calibrated.
If a lens is adjusted properly to digital standards it will certainly be very accurate on a film camera.

 

[Pioneer]

Thanks for your feedback everyone. This is something new for me as I have never had a lens that back focused this badly.

I have tested the Nokton wide open and it was so far off that I felt it had to be the lens. I know my Elmar 50/2.8 isn't exactly fast glass but it is basically right on with this camera. The back focus on the Nokton is far more obvious close up. A lot of my images with the lens have been at further distances so I did not notice this right away, and when I did I just chalked it up to bad technique. But looking back I realize that even some of my longer distance shots were a bit soft in some cases.

I am convinced that the camera's rangefinder is accurate though I will do a bit more testing with a longer lens. I did test the M9 with my newly arrived MS Optical Sonnetar 50/1.1 (what can I say, I love fast glass) and that particular lens is right on the money when focused wide open. In fact, it is so accurate that this is what started me questioning the focus accuracy of the Nokton. If it was my technique, why wasn't my technique just as bad with the new Sonnetar?

Anyway, I contacted Don up at DAG and he is going to make the necessary adjustments. When it gets back I'll take it for another spin and see how things turn out. And Peter, I was with you. I thought that the camera and lens had to be sent together but Don said that wasn't necessary.

 

[jaapv]

The lens and the camera are adjusted separately since 1931 (Leica 1C ) Before that date they were indeed adjusted together, so you guys must be quite senior citizens...😛
Actually the myth originates from two facts:
Many service centers will ask for both lens and camera to make sure that both are adjusted correctly to prevent comebacks and it can be useful to do tolerance matching on extremely critical lenses.

 

[Brian Legge]

Pioneer, what aperture are you shooting? The lens does have focus when you aren't shooting it wide open. I don't have a link handy but there have been some great sample images demonstrating this across apertures posted here in the past.