Musotographer Posted July 1, 2018 Share #1 Posted July 1, 2018 Advertisement (gone after registration) 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. Link to post Share on other sites More sharing options...
Advertisement Posted July 1, 2018 Posted July 1, 2018 Hi Musotographer, Take a look here Collapsible summicron 50 problems after cleaning.. I'm sure you'll find what you were looking for!
TomB_tx Posted July 1, 2018 Share #2 Posted July 1, 2018 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. 3 Link to post Share on other sites More sharing options...
Musotographer Posted July 1, 2018 Author Share #3 Posted July 1, 2018 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 1 Link to post Share on other sites More sharing options...
Ko.Fe. Posted July 1, 2018 Share #4 Posted July 1, 2018 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. 1 Link to post Share on other sites More sharing options...
Big Jim Posted October 10 Share #5 Posted October 10 (edited) Just jumping on this topic to ask if anyone knows what these dots on the 50mm Summicron I was offered could be ? Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Edited October 10 by Big Jim Text Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/286134-collapsible-summicron-50-problems-after-cleaning/?do=findComment&comment=5874048'>More sharing options...
pedaes Posted October 10 Share #6 Posted October 10 (edited) Are you asking about the black mass above the '5cm' engraving? Or the white spots? Edited October 10 by pedaes 1 Link to post Share on other sites More sharing options...
Big Jim Posted October 10 Share #7 Posted October 10 (edited) Advertisement (gone after registration) 12 minutes ago, pedaes said: Are you asking about the black mass above the '5cm' engraving? Or the white spots? I think the black mass is a shadow reflection ? It’s more the white dots above the f= which looks like they are on the back of the front element. I realise now that I asked something similar about another lens and was told “Ifit’s clearly visible that the spots are on the back of the front lens element, then it can’t be separation. There’s also ‘Schneideritis’—but that also occurs between lens elements. Fungus looks different, so that really just leaves dust or particles caused by abrasion of aperture blades. ” Edited October 10 by Big Jim Chrck Link to post Share on other sites More sharing options...
pedaes Posted October 10 Share #8 Posted October 10 I have the previous version and they are known for balsam breakdown 'separation'. These lenses are 75 or so years old. 1 Link to post Share on other sites More sharing options...
Ecar Posted October 10 Share #9 Posted October 10 (edited) Could be early separation, but looks more like Schneideritis to me: over time, the barrel's inner paint and/or the elements' edge paint deteriorates, then flakes off and migrates to the glass. Usually with no ill effect, including on pictures. An easy fix by a competent technician if done in conjunction with a full CLA. Edited October 10 by Ecar 1 1 Link to post Share on other sites More sharing options...
lct Posted October 10 Share #10 Posted October 10 The white spots look like schneideritis indeed. They can appear on the black paint used to reduce internal reflections in lenses but i have no experience with migration to the glass. Mine did not migrate this way and have been cleaned off on a Rokkor 28/2.8 but my 1956 Summicron 50/2 v1 has no spots at all. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/286134-collapsible-summicron-50-problems-after-cleaning/?do=findComment&comment=5874127'>More sharing options...
adan Posted October 10 Share #11 Posted October 10 If "Schneideritis," that is a fairly minor problem, and unlikely to ever matter, except cosmetically. It is basically the same optical phenomenon that makes air bells in ice appear "white" - the difference in refraction-index between the air and the water (or lens glass), as seen against a dark background or substrate. https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Air_bubbles_in_ice_(02).JPG/1024px-Air_bubbles_in_ice_(02).JPG Separation (failure of cement between cemented glass elements) can be ruled out, since the collapsible Summicron has no cemented elements in the front half of the lens (where this is obviously taking place). Only elements 5/6 (behind the aperture) are cemented https://wiki.l-camera-forum.com/leica-wiki.en/index.php?title=File:S502%2B.jpg 1 Link to post Share on other sites More sharing options...
250swb Posted October 11 Share #12 Posted October 11 The top of the photo shows the edges of the lens element and it seems to show Schneideritis and also the spots are not all round but varying shapes, so I'd say it's not an immediate problem and photos won't be affected. Link to post Share on other sites More sharing options...
Alberti Posted October 12 Share #13 Posted October 12 Schneideritis is "a great compositional asset": Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! This was with the 28mm lens above Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! This was with the 28mm lens above ' data-webShareUrl='https://www.l-camera-forum.com/topic/286134-collapsible-summicron-50-problems-after-cleaning/?do=findComment&comment=5875061'>More sharing options...
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