N15M0
Newbie
I have been reading on the web and noticed that there are a lot of clone zeiss jena 5cm floating around. How can I know whether the copy is a original zeiss jena or a clone copy? Thanks.
Zeiss Jena 5cm f/2 Sonnar LTM
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F
former member
Guest
The Sonnar opticl block is easy to identify: matching serial numbers on the front ring, rear optics module, front triplet, and front element. The front element is stamped into a brass mount- which has the Serial number.
Whether this module is original into LTM, or made into an LTM lens after manufacture is not as easy to tell. I remount them using a J-8 focus mount, and I can see that others remounted them into LTM decades ago. some of these used custom made focus mount, all breass, beautiful work. BUT- not original LTM's.
Teardown is here:
http://rangefinderforum.com/forums/showthread.php?t=89797&highlight=sonnar
A collector wants to know, a user wants to know the remount was done well.
Whether this module is original into LTM, or made into an LTM lens after manufacture is not as easy to tell. I remount them using a J-8 focus mount, and I can see that others remounted them into LTM decades ago. some of these used custom made focus mount, all breass, beautiful work. BUT- not original LTM's.
Teardown is here:
http://rangefinderforum.com/forums/showthread.php?t=89797&highlight=sonnar
A collector wants to know, a user wants to know the remount was done well.
N15M0
Newbie
Is there anyway to tell without tearing down the lens?
N15M0
Newbie
Anyway I looked at the link, mine looked different, I don't think mine is a collapsible.
F
former member
Guest
Post some pictures of it.
Our member "Raid" has an original. The LTM version of the 5cm f2 is not collapsible, was a Rigid mount. From what I have seen, Looks like a Single-Helicle, non-collapsoible Summar (rare).
This Sonnar 5cm F2 is one that I made using a 1955 J-8 focus mount.
Our member "Raid" has an original. The LTM version of the 5cm f2 is not collapsible, was a Rigid mount. From what I have seen, Looks like a Single-Helicle, non-collapsoible Summar (rare).
This Sonnar 5cm F2 is one that I made using a 1955 J-8 focus mount.
N15M0
Newbie
Here are some images
F
former member
Guest
First- the lens is a Post-War 5cm F2 CZJ Sonnar.
It looks like a skillfully done remount using a Summitar or Summicron focus mount. The lens goes to F22, the DOF scale goes to F16. SO: if this were an original LTM from the factory, the DOF scale should have extended to F22. It goes to F16, as did the post-war Summitar and the LTM Summicron.
It looks like a skillfully done remount using a Summitar or Summicron focus mount. The lens goes to F22, the DOF scale goes to F16. SO: if this were an original LTM from the factory, the DOF scale should have extended to F22. It goes to F16, as did the post-war Summitar and the LTM Summicron.
N15M0
Newbie
So in other words it's not the original CZJ sonnar?
F
former member
Guest
It is not the original formulation of the 1932 (there abouts) 5cm F2 Sonnar.
After the war, the East German Sonnar "T" 5cm F2 was recomputed. The diameter of the optics are larger, and the optical fixture was completely redesigned.
What you have is the improved Sonnar lens remounted into an LTM focus mount. It is not the original Sonnar lens. It is very good. I had one on a Contax II and gave camera and lens to a friend.
After the war, the East German Sonnar "T" 5cm F2 was recomputed. The diameter of the optics are larger, and the optical fixture was completely redesigned.
What you have is the improved Sonnar lens remounted into an LTM focus mount. It is not the original Sonnar lens. It is very good. I had one on a Contax II and gave camera and lens to a friend.
N15M0
Newbie
Thanks Brian. Initially I was more worried about the lens being a Russian clone.
F
former member
Guest
No chance of that.
You have a custom lens with highly desirable optics. The Russian "clones" usually have re-engraved name-rings. Most I have seen use "SM" instead of "CM" for centimeters!
There were a lot of shops around in "in the day" that did beautiful custom remounts of Sonnar lenses for Leica's. I do them on the Kitchen table using Russian J-8's and J-3's.
I plan on doing a 5cm f2 Sonnar conversion using a Summitar mount. The retaining ring fits into it perfectly, gives something to screw the optics module into.
You have a custom lens with highly desirable optics. The Russian "clones" usually have re-engraved name-rings. Most I have seen use "SM" instead of "CM" for centimeters!
There were a lot of shops around in "in the day" that did beautiful custom remounts of Sonnar lenses for Leica's. I do them on the Kitchen table using Russian J-8's and J-3's.
I plan on doing a 5cm f2 Sonnar conversion using a Summitar mount. The retaining ring fits into it perfectly, gives something to screw the optics module into.
N15M0
Newbie
Thanks brian. Very helpful of you. Now I am not so worried anymore.
