Collapsible summicron 50 problems after cleaning.

[Musotographer]

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Thoughts please. I have a 1955 collapsible Summicron 50, pretty good glass, immaculate cosmetically. I don't use it a lot, but when I do I enjoy it. I decided last autumn that it was a bit hazy and could do with a clean. Nothing else wrong with it, including the focus. I sent it off to a highly respected Leica specialist who had done excellent work on some of my lenses previously, also asking for the infinity lock to be disabled.

 

A couple of months later it came back - haze gone, with the lock disabled as requested, but now with the focus way off, and felt tip markings on the collapsing barrel.

 

I sent it back; about three months later it came back, this time with the barrel clean, the focus a little better, but still not right, and the front and rear caps missing.

 

Back it went, and again after months, and repeated requests for its return, it arrived home this week. The barrel is now clean and both caps restored - but the focus is still off. At f2 it is front focusing by about two inches at a distance of approx. four feet. I have tried it with tripod both on my M10 and M9P, the rangefinders of which are spot on with all my other M lenses, including the f1.4s.

 

Not surprisingly I am somewhat disheartened by all this; I think there is little point in sending the lens back yet again because I doubt that the problem will be solved. I could just use it as is, giving the focus ring a small nudge anti-clockwise to counter the front-focus, or use it only stopped-down, or only with live view, but that is hardly ideal – or I could send it to Leica, but that probably means yet another couple of months without it, and more expense.

 

Any thoughts from anyone familiar with this lens please? Is it known to have problems with  focus wide-open? I am mystified as to why it should be apparently so difficult to get its focus right.

 

[TomB_tx]

The collapsible Summicron does have some focus shift as it stops down, so according to a couple of techs was set up originally to be spot-on at f2.8, so focus would be more acceptable over the full range. This agrees with what I've seen on on my v 1, 2, & 3 Summicrons as factory calibrated.

If recalibrated so f2 is perfect, then f4 would be less sharp, which is normally the better aperture to use for most work.

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[Musotographer]

Thank you Tom - I think that explains it. I have just tried it again, on the tripod, and at f2 it definitely needs a nudge; at f2.8 it needs a smaller one, and at f4 it's almost spot on. Silly of me not to have realised that focus shift could be the culprit (though the person I sent it to didn't mention it either) - but I am still puzzled as to why it initially came back after cleaning so much worse than beforehand. Anyway, it's back home and I know now how to get the best out of it, at whatever aperture. Thanks again.

 

Christopher

[Ko.Fe.]

All 50mm pre-ASPH Crons I have tried have focus shift. Some less, some more. My current one is optimized for f2 at close distances. At f2.8-f5.6 is shifts and at f8 it is back to normal again.

 

If dude who was messing around with yours was able to forget lens caps, he is able to lose or put wrong shimming ring.

 

You never know. I purchased recently LTM camera from high reputable dude and he send me camera with wrinkled curtain, uneven exposures and missing screw.

It looks like they have someone like appraisal and don't bother to check.