SiriusLux Posted August 24, 2014 Share #61 Posted August 24, 2014 Advertisement (gone after registration) I did wonder if they could produce a prime focus version of the Otus 55mm f1.4? However it would be a similar price to the Summilux ASPH, so a difficult sell for Zeiss, no matter how good it was. Wilson Hi Wilson, I do not quite understand what you want to say by "prime focus". The Otus is for Nikon and Canon at present and does feature manual focus, it is as one can understand a fix focal length lens and would - if one wanted - fit on the M using an adapter. What I was referring to was an announcement that Zeiss made in 2012 when they said that they'd add another ZM lens in 2013 to their range, that has been delayed and I was wondering whether anyone had any recent news regarding this lens. Joerg Link to post Share on other sites More sharing options...
Advertisement Posted August 24, 2014 Posted August 24, 2014 Hi SiriusLux, Take a look here What happened to the “surprise” Zeiss ZM Lens. I'm sure you'll find what you were looking for!
wlaidlaw Posted August 24, 2014 Author Share #62 Posted August 24, 2014 Hi Wilson, I do not quite understand what you want to say by "prime focus".The Otus is for Nikon and Canon at present and does feature manual focus, it is as one can understand a fix focal length lens and would - if one wanted - fit on the M using an adapter. What I was referring to was an announcement that Zeiss made in 2012 when they said that they'd add another ZM lens in 2013 to their range, that has been delayed and I was wondering whether anyone had any recent news regarding this lens. Joerg Joerg, The Otus is a retrofocal lens for use on an SLR with a mirror box between the lens mount and the sensor. Therefore its optics are arranged in such a way to have a considerable distance between the exit pupil and the imaging medium. Not only would this make the lens need a spacer to fit a rangefinder camera, with its shorter flange focal distance, it usually means that the elements are larger than they would be on a prime focus lens. For example compare the diameter of the 50mm f1.4 Summilux to the diameter of a typical SLR 50mm f1.4 lens. If Zeiss redesigned the Otus as a prime focus 55mm f1.4, it should be able to be considerably less bulky than it is at present. Wilson Link to post Share on other sites More sharing options...
SiriusLux Posted August 24, 2014 Share #63 Posted August 24, 2014 Joerg, The Otus is a retrofocal lens for use on an SLR with a mirror box between the lens mount and the sensor. Therefore its optics are arranged in such a way to have a considerable distance between the exit pupil and the imaging medium. Not only would this make the lens need a spacer to fit a rangefinder camera, with its shorter flange focal distance, it usually means that the elements are larger than they would be on a prime focus lens. For example compare the diameter of the 50mm f1.4 Summilux to the diameter of a typical SLR 50mm f1.4 lens. If Zeiss redesigned the Otus as a prime focus 55mm f1.4, it should be able to be considerably less bulky than it is at present. Wilson Dear Wilson, I guess we just didn't understand each other, it was quite obvious to me the Otus 55mm is designed in a different way than the Leica-M lenses. Leica M: The "Auflagenmass" (I don't know the term in English, however it is the distance between the planes of sensor and the bayonett) is 27.8mm for the Leica-M system and the acceptable "Schnittweite" (the distance between the rear element and the sensor) can be as little as around 15mm. Canon EF: Auflagenmass 44mm, Schnittweite can be a little below 44mm Looking at the spec sheet of the Otus: http://www.zeiss.de/content/dam/Photography/new/pdf/en/downloadcenter/datasheets_otus/otus_1455.pdf I am quite sure it is not a retrofocus lens since the rear element is behind the bayonett plane (which is 44mm from the sensor) and the focal length is 55mm, so the condition for retrofocus lens (Schnittweite < focal length) is not met. I however get the concept that you are elaborating and I do fully agree. What is still not clear to me is what you meant by "prime focus"? Do you want to say "prime lens" of fix focal length lens vs. Zoom lens (variable focal length)? Regards, Joerg Link to post Share on other sites More sharing options...
wlaidlaw Posted August 24, 2014 Author Share #64 Posted August 24, 2014 By prime focus, I only mean a lens that is not a retrofocal design. I don’t think that the position of the final element position is what controls the definition, as that depends on the flange focal distance. For example, even though the final element of the WATE is behind the mount and on an SLR, with a longer flange focal distance, it would be way behind the mount, it is still classified generally as a retrofocus lens. I have looked on the internet and found no real agreement on the exact definition. Wilson Link to post Share on other sites More sharing options...
SiriusLux Posted August 24, 2014 Share #65 Posted August 24, 2014 By prime focus, I only mean a lens that is not a retrofocal design. I don’t think that the position of the final element position is what controls the definition, as that depends on the flange focal distance. For example, even though the final element of the WATE is behind the mount and on an SLR, with a longer flange focal distance, it would be way behind the mount, it is still classified generally as a retrofocus lens. I have looked on the internet and found no real agreement on the exact definition. Wilson Dear Wilson, in an article of the camera lens blog Zeiss publishes you do find the following statement: "...are retrofocus lenses, in other words non-symmetrical, wide- angle lenses in which the distance between the rear element and the fi lm plane is signifi cantly greater than the focal length." The English version can be downloaded at http://www.zeiss.com/content/dam/Photography/new/pdf/en/cln_archiv/cln38_en_web.pdf The German version can be downloaded at http://www.zeiss.com/content/dam/Photography/new/pdf/de/cln_archiv/cln38_de_web.pdf You will find the quote at the bottom of page 11. I do agree that the wikipedia articles are not quite precise in that respect. Anyways, my initial question was what and when Zeiss will bring us one or two additional interesting lenses for our Leica M. All the best, Joerg Link to post Share on other sites More sharing options...
Dougg Posted August 27, 2014 Share #66 Posted August 27, 2014 ...Anyways, my initial question was what and when Zeiss will bring us one or two additional interesting lenses for our Leica M. All the best, Joerg Yes, by all means let's focus on the question of a new ZM lens as Zeiss announced... As to focal length, as the lineup seems pretty full. So perhaps it would be a faster lens of a focal length already available. Doug Link to post Share on other sites More sharing options...
gberger Posted August 27, 2014 Share #67 Posted August 27, 2014 Advertisement (gone after registration) Due to ageing eyesight, I had to give up my M7 for the ZI's viewfinder. Still using my Leica lenses with the ZI, but I'd like to see a new 24 or 25mm f 2 or f 1.4. Link to post Share on other sites More sharing options...
Peter Branch Posted August 30, 2014 Share #68 Posted August 30, 2014 By prime focus, I only mean a lens that is not a retrofocal design. I don’t think that the position of the final element position is what controls the definition, as that depends on the flange focal distance. For example, even though the final element of the WATE is behind the mount and on an SLR, with a longer flange focal distance, it would be way behind the mount, it is still classified generally as a retrofocus lens. I have looked on the internet and found no real agreement on the exact definition. Wilson Please be careful! Some time ago I got absolutely "torched" by others on this forum for stating that there is no clear agreed definition. An examination of the definitions used by the various manufacturers for "retrofocus" soon shows that they don't agree. It's a bit like a religious belief system - some know the truth and there is only one truth. The term has been used to describe lenses where the back of the rearmost element is further from the sensor than the focal length. This is not the same as the use where no part of the lens is closer to the sensor than the focal length. Equally some simply use the term for any lens where the focal length is shorter than the clearance of the mirror and some where the focal length is less than the distance from the sensor to the flange. Take your pick. Leica use the term "retrofocus like" in their description of the 21mm lenses and the instructions that come with the 18mm SEM states that it is a "retrofocus design". Link to post Share on other sites More sharing options...
wattsy Posted August 30, 2014 Share #69 Posted August 30, 2014 Some time ago I got absolutely "torched" by others on this forum for stating that there is no clear agreed definition. Yes, where's Olaf? I must admit I've never heard of a lens described as a "prime focus" lens though I understand Wilson's explanation of what he means by it. Link to post Share on other sites More sharing options...
lct Posted August 30, 2014 Share #70 Posted August 30, 2014 Leica use the term "retrofocus like" in their description of the 21mm lenses and the instructions that come with the 18mm SEM states that it is a "retrofocus design". The specs say "retrofocus-like design". 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/217212-what-happened-to-the-%E2%80%9Csurprise%E2%80%9D-zeiss-zm-lens/?do=findComment&comment=2660127'>More sharing options...
mirekti Posted August 30, 2014 Share #71 Posted August 30, 2014 So what's with the Zeiss lens? Link to post Share on other sites More sharing options...
wlaidlaw Posted August 30, 2014 Author Share #72 Posted August 30, 2014 Yes, where's Olaf? I must admit I've never heard of a lens described as a "prime focus" lens though I understand Wilson's explanation of what he means by it. He’s only there when you don’t need him :) Lars Bergquist, sadly I believe no longer with us, is the person whose definition I would have like to have heard. Wilson Link to post Share on other sites More sharing options...
wlaidlaw Posted August 30, 2014 Author Share #73 Posted August 30, 2014 The specs say "retrofocus-like design". Can you therefore have a “non-retrofocus-like” design? I could not find a correct term for this, hence my coining of the term “prime focus” to mean the foregoing. Wilson Link to post Share on other sites More sharing options...
Rick in CO Posted August 30, 2014 Share #74 Posted August 30, 2014 So what's with the Zeiss lens? I emailed Zeiss a while ago to ask. They replied no new ZM lens in the near future. The lenses for the Sony a7 series should be readily transferable to ZM mount (already full frame with updated optics). The 55mm f1.8 lens has received some great reviews. Link to post Share on other sites More sharing options...
mirekti Posted August 30, 2014 Share #75 Posted August 30, 2014 The lenses for the Sony a7 series should be readily transferable to ZM mount (already full frame with updated optics). ...but not RF coupled. Link to post Share on other sites More sharing options...
SiriusLux Posted August 30, 2014 Share #76 Posted August 30, 2014 Can you therefore have a “non-retrofocus-like” design? I could not find a correct term for this, hence my coining of the term “prime focus” to mean the foregoing. Wilson Yes Wilson, you can. The best examples are the symmetrical designs, i.e. the Gauss design of the Summicron-M 2.0/50 or the Zeiss Planar design, for example the Planar T* 2.0/50 ZM. In these cases the focal plane is in the center of the lens. The other extreme are telephoto lenses where the focal plane is in front of the front element (or front lens), this would be the opposite of a retrofocus lens. All the best Joerg Link to post Share on other sites More sharing options...
mmradman Posted August 30, 2014 Share #77 Posted August 30, 2014 I emailed Zeiss a while ago to ask.They replied no new ZM lens in the near future. The lenses for the Sony a7 series should be readily transferable to ZM mount (already full frame with updated optics). The 55mm f1.8 lens has received some great reviews. Native Sony A7 lens will not work on Leica M camera, registration distance is 9.8mm short. I understand latest Zeiss lenses for for Sony alpha are repackaged ZM's. Link to post Share on other sites More sharing options...
wlaidlaw Posted August 30, 2014 Author Share #78 Posted August 30, 2014 Yes Wilson, you can. The best examples are the symmetrical designs, i.e. the Gauss design of the Summicron-M 2.0/50 or the Zeiss Planar design, for example the Planar T* 2.0/50 ZM.In these cases the focal plane is in the center of the lens. The other extreme are telephoto lenses where the focal plane is in front of the front element (or front lens), this would be the opposite of a retrofocus lens. All the best Joerg Sorry Joerg, I was being slightly facetious. I was caricaturing manufacturers covering their backsides by describing a lens as retrofocus-like, so if any calls them out on it, they could say: “Well we did not actually say it was a retrofocus lens just retrofocus-like.” Wilson Link to post Share on other sites More sharing options...
Peter Branch Posted August 30, 2014 Share #79 Posted August 30, 2014 The specs say "retrofocus-like design". Indeed. However the actual instruction book with the lens says that it is a retrofocus design - not a retrofocus like design. Link to post Share on other sites More sharing options...
SiriusLux Posted August 30, 2014 Share #80 Posted August 30, 2014 Sorry Joerg, I was being slightly facetious. I was caricaturing manufacturers covering their backsides by describing a lens as retrofocus-like, so if any calls them out on it, they could say: “Well we did not actually say it was a retrofocus lens just retrofocus-like.” Wilson Cool Wilson, I didn't get the funny side of the post :) but you're right, let's not take things too serious. Link to post Share on other sites More sharing options...
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