Archived posting to the Leica Users Group, 2008/03/25
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Let’s not forget that Zeiss has a long history of out-sourcing lens manufacture and components. Voigtl?nder, Bausch & Lomb, Ross, Koristka, Krauss, Kodak and Schneider Kreuznak have all made lenses and lens components for Zeiss. Cosina is just the latest in a long line. There is a weird, beautiful circularity about Voigtl?nder having made lenses for Zeiss, having their name bought by Cosina and then Cosina making lenses for Zeiss. One of the things I admire about Leica is that they are good at coming up with their own designs. Optical design is obviously their forte and they are great at it. So are Zeiss, even if they achieve the end result in a different way. There are a couple of things that make these Cosina-Zeiss lenses particularly interesting to me. One is that they are modern interpretations by Zeiss of their own classic designs. Biogons aint Biogons, in that while the basic design may be similar, these new lenses are carefully considered modern iterations of those classics. For instance, this 35/2.8 differs considerably from the classic Biogons (such as the 35/2.8 for the Contax rangefinders) in that it is a semi-retrofocus design and has obviously been completely recomputed. Why it isn’t called a Distagon I can’t say, but it isn’t. It’s a semi-retrofocus Biogon, because Zeiss says so. I’ll take their word for it. The design philosophy of the Cosina Zeiss lenses is different to the lenses that Cosina design for themselves (and sell as Voigtl?nder – see now why I’m confused?); the out of focus rendition is better and there is a more consistent familial look between focal lengths in the Zeiss lenses. In general, Zeiss use a relatively large number of spherical elements to achieve the end result. Each lens element contributes a small amount, meaning they can mostly be made from glass types that are not partiocularly exotic, expensive or heavy. They can have have excellent optical performance without collimation of each element being ultra-critical. They can do this because their coating technology is so good and because many of the lenses are of specifications that are not pushing the envelope. Some specific aspects of construction are also different between Cosina made Zeiss and Voigtl?nder lenses – this becomes apparent on taking each apart. Mainly there is more care put into making sure that the Zeiss labelled ones hold their elements in the right place. The Zeiss labelled lenses resist flare better, because Zeiss have licensed their T* coating to Cosina for these lenses. Cosina have their own glass making factory and probably have also been licensed to make some proprietary Zeiss glass types for these lenses. That cannot do anything but help optical performance. The closure by Leica of their glass making and research plant was possibly one of the poorer decisions Leica have made – it seems to have resulted in the death of the 75 Summilux and the possible future death of the Noctilux. It's hard to get a third party to make glass for you with cool times that are measured in decades (or even several years). These Cosina made Zeiss lenses are, for the most part, optically superior to both the Zeiss and Kyocera made ones for the Contax SLRs. They benefit from an additional 25+ years of optical design, glass and coating technology. They benefit from an additional 30-40+ years of those things over the Contarex lenses. My German-made Zeiss AE lenses for my Aria were not particularly mechanically good (particularly my sample of the 50/1.4, which had quite a bit of play in the front optical cell) and while the Kyocera MM made ones were definitely more lightly constructed and featured more plastic, they were optically better. A lot of this was probably connected to the introduction of new lens designs or redesigns around the time the location of manufacture changed. Discussions about Zeiss always conjurs up the Contarex. The Contarex stuff is mightily impressive, but not necessarily to the benefit of the user. 30+ years of glass and coating development has made a lot of difference to optical capabilities. Any camera lenses that are as difficult to service as are the Contarex lenses are not the ‘ultimate’ lenses. Anyone who has patiently heated a Contarex lens barrel to make it let go of a seated element or tried for hours to remove a seating ring without wrench slots would probably concur, without even mentioning focus problems caused by the lack of space to shim lenses for proper infinity focus. It’s also unlikely that these lenses are cemented with resins which will separate as readily as the Contarex ones do or that the lubricants will be disastrously short lived. That's without even looking at the bodies. The factory workers who made the Contarex black finish on brass by dipping the machined components into molten cyanide salts would probably agree that modern black finishes are better too. I’ve used borrowed individuals of the Cosina made ZM 25/2.8, 35/2 and 50/2 and several of the SLR lenses. They’re all spectacular. I am sure that the ZM 15 and 85 are stupendous, but I haven’t used them. I don’t know anyone who has one that I can borrow either. If we’re talking about performance alone, the Cosina made lenses are arguably the optically best 35mm format ‘Zeiss’ lenses ever made. It still doesn’t really make them ‘Zeiss’ lenses, but their optical qualities and the photos they give are remarkably good. What you or I think of them relative to Leica lenses is more a matter of taste than objective quality, since both are so good you’re unlikely to see any serious optical flaws become apparent in pictures taken with either brand. Our Leicas aren’t all Leica either. Hoya is good enough for Leica to get some of the blanks for some of their lens elements from them. Zeiss is Neiss and I like Leica, by whoever and wherever they're made. It’s the pictures that count. Marty Gallery: http://gallery.leica-users.org/main.php?g2_itemId=7617 -- Want an e-mail address like mine? Get a free e-mail account today at www.mail.com!