Deliberate1 Posted December 19, 2015 Share #1 Posted December 19, 2015 Advertisement (gone after registration) Friends, I just purchased a certified Leica for Contax 645 adapter and am exploring the options. First question has to do with the filed of view. I have become accustomed to converting the native S lens to 35mm using a factor of .8. The 70mm Summarit I have "sees" as a 56mm full frame would see, if I have this right. As I was reading through that excellent discussion on Getdpi (sorry, but the link would not display) I came across the following: The Contax 35mm was designed and made for a 645 film camera. It will give the field of view that you would expect from a 35mm lens on a 645 camera (or even a 6x6 camera).If you use it to expose a 30x45mm area, you are not using the full 645 (6x6) area and therefore, rather unsurprisingly, the field of view will not be the same. It will in fact be similar to a 43mm lens on a 645 camera. The point being, do not expect your Contax 35mm to give you the same field of view on a Leica S2, as it does on your Contax 645. Made sense to me that a lens designed 645 or 6x6 format would be interpreted differently by the smaller S sensor. Someone suggested that the factor would be 1.25. If so, would the 80mm Contax have the same field of view as a 100mm in S terms? If so, this lens, a darling of the Contax line, would be a very nice short tele/portrait lens, and walk-about lens given its speed and size. And the 120mm Makro, which is lauded as one of the best in the herd, would be in the range of 160mm. Again, if my extrapolation is correct, there is no lens on the wide end that would get me a wide (say, 35mm in 35mm terms), as the widest is the 35mm Distagon T which would draw the equivalent of a 44mm (appx) in S terms. And that is too close to the 70mm Summarit that I have (56mm in 35mm). Please let me know if my math is right, and especially with respect to the 80mm and 120mm. Keeping the adapter only makes sense if I can use it on multiple Contax lenses. On the long side, the two Contax options are very attractive. But on the wide end I may be skunked. Of course there are the 35mm or 45mm Leica gems. Appreciate any insight into the use of these Contax lenses in the two years since the adapter was released, I know that more than a few of you folks (means you, Dirk) have waxed rhapsodic about the Zeiss on S fusion. Much obliged, David Link to post Share on other sites More sharing options...
Advertisement Posted December 19, 2015 Posted December 19, 2015 Hi Deliberate1, Take a look here Adapted Contax lens questions . I'm sure you'll find what you were looking for!
siddhaarta Posted December 19, 2015 Share #2 Posted December 19, 2015 No, the "field of view factor" is the same as with S lenses, as you are mounting the Contax lenses on the S with the S-size sensor. The adapter only adjusts the distance to the sensor. The other poster meant divide by 1,25 which is the same as multiply by 0,8. 80mm Contax Planar would correspond to 64mm field of view (but the character is so much different from the 75mm Leica, that I would buy the adapter only for this lens) 120mm would be 96mm field of view (don't think I would buy this one over the Leica Apo Macro 120mm, if it is not for the price, of course) 35mm would be 28mm field of view (again I would prefer the 35mm from Leica, if it is not for the price) Link to post Share on other sites More sharing options...
Deliberate1 Posted December 20, 2015 Author Share #3 Posted December 20, 2015 No, the "field of view factor" is the same as with S lenses, as you are mounting the Contax lenses on the S with the S-size sensor. The adapter only adjusts the distance to the sensor. The other poster meant divide by 1,25 which is the same as multiply by 0,8. I do not think that was the calculation. Another contributor posted the following: Well, how the edges are doesn't really matter. The Leica S chip is 30x45mm, so it will never see the edges of any of these lenses. The 35 becomes a 43 (x1.25) Anyone else? Link to post Share on other sites More sharing options...
ocean2059 Posted December 20, 2015 Share #4 Posted December 20, 2015 No, the 35mm in Contax 645 lens is the same of the 35mm Leica S lens which is equivalent of 28mm (35mm/1.25 = 28mm), not 43mm. Link to post Share on other sites More sharing options...
siddhaarta Posted December 20, 2015 Share #5 Posted December 20, 2015 You said, "someone suggested that the factor would be 1,25". So I interpreted this without knowing the context. With regards to the text, cited from Getdpi, that is totally correct as the poster compares field of view between Contax 645 (41,5x56 negative size) and Leica S (30x45). You asked about comparison between field of view of Leica S (30x45) and FF (24x36). Sometimes very confusing, indeed. So what he said is that e.g. the Contax 35mm Distagon is a much stronger wide angle lens (about a 21mm field of view on FF) on the Contax 645 than on the Leica S (a 28mm field of view on FF), because of the bigger negative format of the Contax compared to the digital sensor size of the Leica S. If you put that Contax Distagon on a Leica SL (FF body), you would have a moderate 35mm wide angle field of view. Truth also is, you can not compare field of views directly between a sensor with a 2:3 ratio with an analog film with a 3:4 ratio. On the other hand, the Leica S sensor has the same 2:3 ratio as FF. Link to post Share on other sites More sharing options...
peterv Posted December 20, 2015 Share #6 Posted December 20, 2015 The Contax 35mm will give the same FOV as a native S 35mm, simple as that. The same goes for any other 35mm lens that was originally designed for an image size larger than 30 x 45mm, with a diagonal larger than ~54mm which is the diagonal of the S sensor. I and others have explained this ad nauseum in that same getDPI thread. Link to post Share on other sites More sharing options...
Guest chipcarterdc Posted December 21, 2015 Share #7 Posted December 21, 2015 Advertisement (gone after registration) Appreciate any insight into the use of these Contax lenses in the two years since the adapter was released, I know that more than a few of you folks (means you, Dirk) have waxed rhapsodic about the Zeiss on S fusion. Much obliged, David I've posted some impressions here: http://forum.luminous-landscape.com/index.php?topic=106679.0 (I can't figure out how to embed images on this forum) Link to post Share on other sites More sharing options...
pop Posted December 21, 2015 Share #8 Posted December 21, 2015 How do I upload photos to the forum? Link to post Share on other sites More sharing options...
BerndReini Posted December 25, 2015 Share #9 Posted December 25, 2015 The 80mm Contax lens MOUNTED ON THE S will have the approximate field of view as a 100mm lens MOUNTED ON THE CONTAX 645. Does this explain it? Link to post Share on other sites More sharing options...
Guest chipcarterdc Posted December 25, 2015 Share #10 Posted December 25, 2015 Here's another way to look at this, perhaps more intuitive to those used to translating 645 to 35mm terms rather than translating the Leica S sensor area to 645 terms, then back to 35mm terms. (1) The native Leica 70mm renders on the Leica S approximately as a "normal" 50mm lens would on a 35mm camera. (2) The 80mm Contax is slightly longer (10mm) than the Leica 70. (3) Thus, when putting the Contax 80mm on the Leica S, the resulting look will be slightly longer than a standard normal lens looks on a 35mm camera. Link to post Share on other sites More sharing options...
Deliberate1 Posted December 25, 2015 Author Share #11 Posted December 25, 2015 Appreciate the explanations. Two days ago I bought the Contax 35mm 3.5 with the assumption that it will have the approximate field of view of a 28mm on my S. Would certainly prefer to populate my quiver with all Leica glass, but the 4x to 5x cost ratio is irresistible and people wax rhapsodic about these lenses. Very nice of Leica to make option this possible - especially with a device that permits these lenses to work as native on the S. I remain on the lookout for a Planar 120mm Macro as well. The two Zeiss lenses along with my 70mm Summarit will make a nice early quiver. Best regards to all. David Link to post Share on other sites More sharing options...
alan.y Posted December 31, 2015 Share #12 Posted December 31, 2015 Hi David, would love to see some shots from your Contax 645 lenses on the S. Not many of these available online. I think the Contax 45/80/140 combo would work very well for me in terms of fov as well as cost and portability. Link to post Share on other sites More sharing options...
Deliberate1 Posted December 31, 2015 Author Share #13 Posted December 31, 2015 Hi David, would love to see some shots from your Contax 645 lenses on the S. Not many of these available online. I think the Contax 45/80/140 combo would work very well for me in terms of fov as well as cost and portability. Alan, the 35mm is on its way. Information I have gleaned suggests that the 45mm is not the strongest link in the chain - that it is prone to softness in the edges. But because the S sensor is smaller than the 645 format, I was told that should not be an issue. They are cheaper than the 55m which gets very good reviews. You can read about the 80mm which, I am told and have seen, has a character all its own. It is the priciest - going for $1200-1500+/-. I have read nothing about the 140mm, which go for $300-400 on Ebay. The star is the120mm macro which gets universal praise. Can be yours for $800-900. The expensive part of the process is the Leica adapter that retails for about $2k. If you keep your eyes open, you can find them used from Leica stores. I got a certified one from Leica Miami for half that. There was one at Leica Soho that went for $900 recently - I missed that one. While I would love to fill my camera bag with authentic Leica glass, the pragmatist in me notes that for the cost of a new Summarit S 120mm, I can get the adapter and four Zeis lenses, with a few coins left over. All that said, I do love my 70mm.... Regards, David Link to post Share on other sites More sharing options...
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