M9 + Summicron 90mm ASPH APO Focus Problem

[DavidM9]

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I placed my M9 + Summicron 90mm ASPH APO on a tripod and took pictures of a shaving foam can (at F2 & F4) at different distances (from 1m to 5m in 1m increments). I found that at 1m, the focus was spot-on and very sharp. From 2m onwards, I had to adjust the focal distance a little forward (i.e. instead of 2m, adjust to just less than 2m so the two focus rings don't quite join together) to get the sharpest picture. Is this known as "back focus" problem and should I adjust the way I focus objects to get a sharp picture or should I send the 90mm lens in to Leica agent to adjust. I have no problems focusing sharply with my 50mm Summilux

 

Any advice?

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[jaapv]

How is the lens at 3m and 10 m?

[charles-k]

I had a 50 Lux Asph bought second hand. It was sharp at MFD and at infinity, but mid distances was way off. Sent away to Solms, and the lens is great now.

 

I also purchased the 90 Cron AA second hand too, MFD and infinity seemed fine, but mid distances it would inconsistently focus. The problem with the 90 Cron AA was confirmed the Leica agent, and is now at Solms.

 

Fortunately I have had the M9 accurately calibrated with the local agent, so I had the confidence to know the problems were the lenses.

[DavidM9]

Hi. The lens at 3m distance displays the same problem as at 2m, 4m or 5m. I have not tried at 10m. Is there any reason why you asked about 3m and 10m?

[jaapv]

Those are the normal adjustment distances. It seems the helicoid needs adjusting. I would send it in if I were you.

[DavidM9]

Oh dear. I was hoping to avoid sending the lens in. Do you know if this needs to go back to Solms or can the local Leica appointed Agent servicing center manage this

[jaapv]

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I don't know where you are, but a qualified leica repair person can do the job.

[DavidM9]

I took a series of photos with my 50mm Summilux ASPH at distances from 1m to 5m to check if the focus problem was only with my 90mm Summicron. Here are the results:

- 90mm Summicron (at F2): sharp at 1m, then from 2m to 5m need to reduce focal distance a notch to get sharp pictures

- 50mm Summilux (at F1.4): sharp at 1m and 2m, then from 3m to 5m need to reduce focal distance a small notch (less than for 90mm lens) to get sharp pictures

 

Does this mean the problem could be with my M9, or perhaps with everything?

 

Do you think this needs sending M9 + lenses to Solms, or just to the local Leica repair center?

 

What needs to be done exactly?

[jaapv]

If the camera behaves the same with both lenses it seems to me that the camera is at fault, not the lenses. Then you need to send the whole set in, but not neccesarily to Leica. A third-party repair person can do the job. Otoh, there might be a guaranty thing if you send it to leica.

[bocaburger]

That is very odd behavior but it sounds like the intermediate-distance adjustment of the rangefinder is at fault. I've heard of that adjustment but I confess I've never seen or heard how it's done, and that it is rarely if ever needed once the camera leaves the factory (unless it leaves the factory maladjusted). Typically if the rangefinder is adjusted for infinity and 1m (those adjustments are easily made through the lens opening in the body) unless there's something amiss with the lens cam, things should focus correctly at all distances. That's always been my experience. In this case, although 2 lenses is a very small sample, I would be tempted to just send the camera to be checked and readjusted. If you could get ahold of a few more lenses which are known to focus properly on other bodies...or, try your lenses on another body...you would have more evidence.

[DavidM9]

Thank you for your advice. I tried my M9 with a friend's Summicron 90mm (non-ASPH) and had the same focus problems. I am also going to try my own Summicron 90mm ASPH APO with another M9 body to see what happens. Then I hope to have a comprehensive picture to present to Leica or their agent. Stay tuned

[ianspector]

Dear David,

 

I have been sending my new 90 Summicon backwards and forwards to Solms for exactly a year. The first two times it came back like yours but I got it back last time and now everything over 3m is stunningly sharp. I suspect that these lenses are not easy to have accurate focus at near and far distances. I recommend that you buy by 90mm from me and use that for 3m and over and yours for less than 3m. This seems to be a Leica solution.

 

Sending everything to Solms at the same time is your best shot at getting it sorted. I did not as every other lens that I owned worked fine.

 

Ian