marknorton Posted May 28, 2009 Share #21 Posted May 28, 2009 Advertisement (gone after registration) OMG, I can see an "Anatomy of the 0.95 Noctilux" thread coming Not from me you won't! Quote Link to post Share on other sites More sharing options...
Advertisement Posted May 28, 2009 Posted May 28, 2009 Hi marknorton, Take a look here Noctilux 0.95 - stiff focus. I'm sure you'll find what you were looking for!
Guest darkstar2004 Posted May 29, 2009 Share #22 Posted May 29, 2009 I remember when I got my Noctilux new in 1983. It had the stiffest focusing of all my lenses. Now, 26 years later--it's smooth as silk. So. . .26 years?My last of the last Noctilux f/1.0 is very stiff, too. Perhaps they are built that way so that they won't be sloppy loose a decade or two down the road - just a thought... Quote Link to post Share on other sites More sharing options...
marknorton Posted May 29, 2009 Share #23 Posted May 29, 2009 What's interesting with the old Noctilux is how much smoother the focussing action is if you hold the lens by the lens barrel compared to holding the lens by the (rear) lens cap, at least on mine, and it's been the same across various trips to Solms. That tells me the weight of the lens barrel is the problem and that the focussing mount is not really up to the job for this lens. There isn't the same effect with the two new Summiluxes and I'm hoping there won't be in the new Noctilux. Quote Link to post Share on other sites More sharing options...
wizard Posted May 29, 2009 Share #24 Posted May 29, 2009 What's interesting with the old Noctilux is how much smoother the focussing action is if you hold the lens by the lens barrel compared to holding the lens by the (rear) lens cap, ... Mark, I noticed the same effect on my Summicron-M 2/90 asph. That tells me the weight of the lens barrel is the problem and that the focussing mount is not really up to the job for this lens. There isn't the same effect with the two new Summiluxes and I'm hoping there won't be in the new Noctilux. It's most likely not the weight of the lens barrel itself, but of the heavy lens elements carried by the lens barrel. And I wouldn't say the focussing mount is not really up to the job. Rather, I believe it's good old basic physics: All that heavy glass in lenses like the Noctilux or the 90 asph creates pressure on the focussing helicoil, and in turn generates higher friction forces than in other lenses having smaller lens elements. When turning the focussing ring, you simply feel that effect. With the 90 asph, the situation is worsened by the fact that most of the lens elements are located to the front of the lens, so the lever arm acting on the focussing mechanism is quite large. The only solution in my view would be to use a longer focussing helicoil, such that forces are distributed over a larger area and more evenly lenghtwise. And exactly that solution IS used with lenses for SLR cameras. M lenses need to be compact though, so I reckon we will have to live with this problem. Regards, Andy Quote Link to post Share on other sites More sharing options...
marknorton Posted May 29, 2009 Share #25 Posted May 29, 2009 By the "weight of the lens barrel", I did of course mean to include the weight of the glass it contains... Whether it's the size or precision of the focussing mechanism, or the lubrication used, the old Noctilux focussiing makes an already difficult to use lens more so. My brief look at the new lens at Photokina left me with the impression it's much improved. Quote Link to post Share on other sites More sharing options...
jaapv Posted May 29, 2009 Share #26 Posted May 29, 2009 Mark, I noticed the same effect on my Summicron-M 2/90 asph. I would say that is not typical. Mine has the effect minimally or not at all. Quote Link to post Share on other sites More sharing options...
marknorton Posted May 29, 2009 Share #27 Posted May 29, 2009 Advertisement (gone after registration) I would say that is not typical. Mine has the effect minimally or not at all. Same here, my 90AA is fine. Quote Link to post Share on other sites More sharing options...
wizard Posted May 29, 2009 Share #28 Posted May 29, 2009 Mark, Jaap, do you want to tell me there's no difference in focussing feel when you hold your 90 asph by the lens barrel, at the front that is, and turn the focussing ring, as opposed to holding the lens close to its mounting flange? I almost can't believe that. Of course, you are supposed to hold the lens in a horizontal position, not vertically, otherwise it does not make any difference indeed. Regards, Andy Quote Link to post Share on other sites More sharing options...
marknorton Posted May 29, 2009 Share #29 Posted May 29, 2009 No difference to speak of whereas it's night and day different on the old Noctilux, or at least my example of it. There's actually no difference when the lens is held horizontally compared to vertically. Quote Link to post Share on other sites More sharing options...
luigi bertolotti Posted May 29, 2009 Share #30 Posted May 29, 2009 When Leica designed the M rangefinder, the distance the focussing roller moves as you focus down from infinity to closest focus was likely not chosen by waving a finger in the air. It's about the distance the lens barrel moves out in a 50mm lens and means these lenses can use a single helicoid with a profiled cam attached to the lens barrel pressing against the roller. If you then go to 21mm or 90mm, the distance the lens barrel moves is very different compared to the distance the roller (still) has to move. Very small in the 21mm, much larger in the 90mm. That requires a double helicoid with different pitches so that turning the focussing ring moves the lens barrel at one rate and the focussing cam at another. If there's a close focussing group, this has to be moved as well adding more complexity and friction to the focussing mount, hence the heavier focussing action. I do wonder how they fit everything into the available space in the Noctilux lens mount. It's very full in the old lens (which does not have close focus correction), it's very full in the 50mm Summilux ASPH which does, so how they fit f0.95 and close focus correction in there will be interesting to see. I gave a look to the "Engineering drawing" that is onto the pdf brochure of the Noctilux... I think it's under-detailed: judging from the drawing, there is no evidence of how the floating group is moved... it's composed by the two rear elements, and they look as their position towards the next group of two elements should be rigid. Quote Link to post Share on other sites More sharing options...
brianv Posted May 30, 2009 Share #31 Posted May 30, 2009 I don't have the Leica lens, but find the "heavy but smooth" focus of my Canon 50/0.95's necessary for accurate focus. You do not want to overshoot, and cannot focus "too" quickly with these super-speed lenses. The Helical cannot have any play in it with such fast optics. I should add that it is not loose or sloppy in its 5th decade. Quote Link to post Share on other sites More sharing options...
jaapv Posted May 30, 2009 Share #32 Posted May 30, 2009 Mark, Jaap, do you want to tell me there's no difference in focussing feel when you hold your 90 asph by the lens barrel, at the front that is, and turn the focussing ring, as opposed to holding the lens close to its mounting flange? I almost can't believe that. Of course, you are supposed to hold the lens in a horizontal position, not vertically, otherwise it does not make any difference indeed. Regards, Andy No - I have to fantasize to feel a difference. Quote Link to post Share on other sites More sharing options...
marknorton Posted May 30, 2009 Share #33 Posted May 30, 2009 (edited) I gave a look to the "Engineering drawing" that is onto the pdf brochure of the Noctilux... I think it's under-detailed: judging from the drawing, there is no evidence of how the floating group is moved... it's composed by the two rear elements, and they look as their position towards the next group of two elements should be rigid. Yes, I don't think they're giving away much with those "engineering drawings"... Edited May 30, 2009 by marknorton Quote Link to post Share on other sites More sharing options...
luigi bertolotti Posted May 30, 2009 Share #34 Posted May 30, 2009 (edited) Yes, I don't think they're giving away much with those "engineering drawings"... ... But they are rather good for making a decent CAD 3D Solid Model... , I'm doing my "personal vrtual collection".. (btw, M8 is easier to model than previous Ms... less 2nd order curves... ) Edited May 30, 2009 by luigi bertolotti Quote Link to post Share on other sites More sharing options...
marknorton Posted May 30, 2009 Share #35 Posted May 30, 2009 Interesting, for the Leica man who has everything, replica Leica lenses in exotic woods made from your 3D designs. I'll take the Noctilux in cherry, the 21mm Summilux in birds-eye maple and the APO 90 Summicron in rosewood... Quote Link to post Share on other sites More sharing options...
luigi bertolotti Posted May 30, 2009 Share #36 Posted May 30, 2009 Interesting, for the Leica man who has everything, replica Leica lenses in exotic woods made from your 3D designs. I'll take the Noctilux in cherry, the 21mm Summilux in birds-eye maple and the APO 90 Summicron in rosewood... Applying some exotic textures on the CAD model is already rather funny...... I'll made some post, one day...... even the glass can be given some fine hue, too... Quote Link to post Share on other sites More sharing options...
marknorton Posted May 30, 2009 Share #37 Posted May 30, 2009 Well, the nice thing about having a virtual lens collection is that you never need to send them in for a CLA and back-focussing doesn't exist in the virtual world. Quote Link to post Share on other sites More sharing options...
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