stunsworth Posted January 18, 2010 Share #21 Posted January 18, 2010 Advertisement (gone after registration) I think those of you who came with explanations still didn't see what Steve and I saw - that there's no difference between "Volcanic silica" and "Volcanic silica". Exactly Link to post Share on other sites More sharing options...
Advertisement Posted January 18, 2010 Posted January 18, 2010 Hi stunsworth, Take a look here Leica Glass. I'm sure you'll find what you were looking for!
jaapv Posted January 18, 2010 Share #22 Posted January 18, 2010 Apart from a few glasses specially made to recipes from the old Leica glass laboratory, Leica use glass from the catalogs of the major manufacturers, just as everybody else does.The old man from the Screwdriver Age A case in point being the Tri-Elmar. Leica would still be making this lens, were it not that Hoya could (would???) no longer supply the raw blanks for the front lenses. Leica tried to use another supplier, but this unnamed supplier was unable to produce the desired quality consistently. So Leica had to stop making this lens. Not that they were very sorry, as it was a very elaborate lens mechanically and they could use the production space to catch up with backorders. Link to post Share on other sites More sharing options...
delander † Posted January 18, 2010 Share #23 Posted January 18, 2010 Canon used artificial (lab-grown) fluorite crystal in place of glass for a while in their early 300 f/2.8 lenses - they may still use it on occasion: Canon Advantage - Fluorite and UD Glass - Canon USA Consumer Products. All current Canon large aperture super telephotos 200-800mm have a fluorite element as do the 70-200 F4 and 70-200 F2.8 (latest version) zooms. I notice that in the data sheet for the Leica APO 75 summicron M it is stated that element number 2 is a 'fluorite type'. I dont know exactly what this means - real fluorite or? I dont see fluorite claimed in the DS for the ASPH 50 summilux M. Jeff Link to post Share on other sites More sharing options...
jaapv Posted January 18, 2010 Share #24 Posted January 18, 2010 Fluorite lens elements have one disadvantage: they can oxidize and age. So they can best be used in the middle of kitted triplets or in nitrogen-filled lenses. If not the lens will have a limited life-span, albeit still a reasonable number of years. Link to post Share on other sites More sharing options...
Fokalfissur Posted January 18, 2010 Share #25 Posted January 18, 2010 "modern" glass tecnology started with Ernst Abbe and Otto Schott and Carl Zeiss. Experiments and use of rare earth elements started early. Optical glass demands very pure raw materials and a unique melting technic. The batch is melted in furnaces with fused silica or even platinum linings to prevent contamination from refractory material. The refinement (the desoption of bubbles) is very important and need high temperatures and a long time. The controled cooldown of the glass is of the same importance to avoid tensions. Optical glass is usually delivered in bars. Thus the cutting and grinding and surface treatment should be made inhouse at Leica. As far as I know Leica didn't want to buy glass from it's somewhat competitor (Schott and Zeiss are strongly linked) and they bought from Corning. However, I think that has changed for quite a while now. Schott has a huge catalog for standard optical glass (…and the production in Mainz is just a 100 km down south of Solms). Things get special if you want to have produced a unique glass with special properties just for your use and Leica don't want to put Zeiss on it's development trail… Link to post Share on other sites More sharing options...
wizard Posted January 18, 2010 Share #26 Posted January 18, 2010 ...but this unnamed supplier was unable to produce the desired quality consistently. It was Kyocera, a company that is known to have manufactured other (good) lenses for Leica in the past (35 - 70/4 and 80 - 200/4 R lenses for example). This just shows that Leica lenses operate at the very limit of what is possible in todays optical construction. Kyocera did supply some front lens elements for the MATE when Hoya stopped to do so, but as Jaap correctly mentioned, Leica had great problems in tuning the MATE-lenses using the Kyocera element to deliver the designed performance. Which is why Leica eventually stopped making that lens. Andy Link to post Share on other sites More sharing options...
offshore Posted January 18, 2010 Share #27 Posted January 18, 2010 Advertisement (gone after registration) I think those of you who came with explanations still didn't see what Steve and I saw - that there's no difference between "Volcanic silica" and "Volcanic silica". Look at the original sentence. It's obviously a typo, but it means that one of them (which one?) probably is not Volcanic silica. And if not, what is it then? Because in Japan it's pronounced sirica and in Germany silica. Did I say that out loud? Link to post Share on other sites More sharing options...
ho_co Posted January 18, 2010 Share #28 Posted January 18, 2010 I think those of you who came with explanations still didn't see what Steve and I saw - that there's no difference between "Volcanic silica" and "Volcanic silica". ... I think what you and Steve saw is obvious. That's why I played on the non-distinction in post 18. And I thank Jaap for his post 22 elucidation of my mention of the reason for the discontinuation of the Tri-Elmar in post 18. Link to post Share on other sites More sharing options...
hoppyman Posted January 19, 2010 Share #29 Posted January 19, 2010 It was Kyocera, a company that is known to have manufactured other (good) lenses for Leica in the past (35 - 70/4 and 80 - 200/4 R lenses for example). This just shows that Leica lenses operate at the very limit of what is possible in todays optical construction. Kyocera did supply some front lens elements for the MATE when Hoya stopped to do so, but as Jaap correctly mentioned, Leica had great problems in tuning the MATE-lenses using the Kyocera element to deliver the designed performance. Which is why Leica eventually stopped making that lens. Andy That's very interesting Andy. I have owned a number of Contax (Kyocera) products which I always found worked very well. Can you provide a link to the information that you have quoted? I was aware of Schott, Hoya and Ohara (I saw many hundreds of pressed blanks from Ohara in Solms) as glass suppliers for Leica but had not heard of Kyocera made glass. Link to post Share on other sites More sharing options...
rsolomon Posted January 19, 2010 Share #30 Posted January 19, 2010 They are of course not insensitive to the market, but their market niche is top notch optics, and they know it. I could not agree more with this statement, this is the cornerstone of Leica...NOT cameras..... realizing they produce very fine camera bodies - Leica really about lenses Link to post Share on other sites More sharing options...
redbaron Posted January 19, 2010 Share #31 Posted January 19, 2010 I could not agree more with this statement, this is the cornerstone of Leica...NOT cameras..... realizing they produce very fine camera bodies - Leica really about lenses That's why lenses get top billing in all Leica advertising. What a load of rubbish. Link to post Share on other sites More sharing options...
rsolomon Posted January 19, 2010 Share #32 Posted January 19, 2010 Leica is about optics... and providing the tool to produce the highest possible image quality in its class. Do you think your opinion matters.... great comment about Leica advertising..... do you see a lot of Leica advertising ? Link to post Share on other sites More sharing options...
redbaron Posted January 19, 2010 Share #33 Posted January 19, 2010 Leica is about optics... and providing the tool to produce the highest possible image quality in its class. Do you think your opinion matters.... great comment about Leica advertising..... do you see a lot of Leica advertising ? Hmm... From memory, I think Leica has a website. My opinion is probably worth just about the same as yours. Or are you special? Link to post Share on other sites More sharing options...
rsolomon Posted January 19, 2010 Share #34 Posted January 19, 2010 Really, no offense but i can see where we are different - I don't consider the leica website advertising - guess you might consider it since it shows their product line.i would use the more traditional definition: 1.the act or practice of calling public attention to one's product, service, need, etc., esp. by paid announcements in newspapers and magazines, over radio or television, on billboards, etc.: to get more customers by advertising. 2.paid announcements; advertisements. I only asked if you think your opinion matters - nothing implied just curious if you thought so. certainly no opinion is worth any more than anyone else's -unless he's the boss. You used the term "rubbish" on my opinion, that was the reason i asked. Link to post Share on other sites More sharing options...
twittle Posted January 19, 2010 Share #35 Posted January 19, 2010 great comment about Leica advertising..... do you see a lot of Leica advertising ? I saw a Leica ad in a European edition of National Geographic about fifteen years ago, and yes, it was about lenses. Link to post Share on other sites More sharing options...
nhabedi Posted January 19, 2010 Share #36 Posted January 19, 2010 Leica does have ads in photo magazines (at least here in Germany) from time to time. And, yes, those ads are usually for cameras... Link to post Share on other sites More sharing options...
wizard Posted January 19, 2010 Share #37 Posted January 19, 2010 Can you provide a link to the information that you have quoted? I was aware of Schott, Hoya and Ohara (I saw many hundreds of pressed blanks from Ohara in Solms) as glass suppliers for Leica but had not heard of Kyocera made glass. Geoff, I got this information directly from a member of Leica's optical department at the international forum meeting in 2008 (I believe it was 2008). And I do not know whether Leica regularly uses Kyocera as a supplier for lens elements, but they tried to do so in that particular case. Maybe because Kyocera has lots of expertise in ceramics, they were believed to be capable of producing the required ceramic mould for the aspheric front element of the MATE in the same way that Hoya was using, but that is pure speculation on my part. Also, I doubt that there are any official links showing which suppliers Leica (or any other lens manufacturer) uses for lens elements. Regards, Andy Link to post Share on other sites More sharing options...
lars_bergquist Posted January 19, 2010 Share #38 Posted January 19, 2010 The MATE had two aspherical surfaces. I do not know if the front lens had one of them, but if that was the case, it was definitely not produced by moulding, but by grinding and polishing, because of its large diameter. Even if Kyocera had the ability, I think it would have been unlikely that Leica would have obtained a finished front element from Kyocera. As I heard the story, the glassmaker could not deliver the glass, i.e. the requisite blanks. I do not think Leica buys finished lens elements from any outside source, only blanks. The old man with the aspherical glasses Link to post Share on other sites More sharing options...
wizard Posted January 19, 2010 Share #39 Posted January 19, 2010 Yes, Lars, the front element of the MATE has an aspheric surface. And no, Lars, it was not the glass, but the lens element itself which could not be obtained by Leica in the required precision from another manufacturer once the original manufacturer had terminated supply to Leica. I was assuming that this lens element was produced by precision moulding, as no lens element of the MATE has a truly large diameter, but I may be wrong on that. The conversation I had with the Leica employee seemed to imply that the lens element in question was produced by precision moulding. Andy Link to post Share on other sites More sharing options...
jaapv Posted January 19, 2010 Share #40 Posted January 19, 2010 The MATE had two aspherical surfaces. I do not know if the front lens had one of them, but if that was the case, it was definitely not produced by moulding, but by grinding and polishing, because of its large diameter. Even if Kyocera had the ability, I think it would have been unlikely that Leica would have obtained a finished front element from Kyocera. As I heard the story, the glassmaker could not deliver the glass, i.e. the requisite blanks. I do not think Leica buys finished lens elements from any outside source, only blanks. The old man with the aspherical glasses I was not talking about polished elements, but about blanks, Lars, so you are correct. I seem to remember that the blanks were used in Leica's blankpressing technique, I don't think they polish to aspherical any more. Link to post Share on other sites More sharing options...
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