|Posted: Thu May 09, 2013 9:02 pm Post subject: Schneider Tele-Xenar 18cm f/5.5 for Reflex Korelle
|I spotted this on ebay for what it was, a rather uncommon lens -
This Schneider was made sometime between 1939 and 1942 according to the serial number, so most likely it is wartime production. The mount is almost certainly for the Reflex Korelle, the pre-WWII versions, that had an M41x1 screw mount. The Kochmann Reflex Korelle was an early interchangeable lens 6x6 SLR. The Korelles switched to different mounts (bayonet and then a larger screw) in later models. This distinctive lens has also been documented in pre-war Korelle sales materials, though with an black enameled barrel instead of nickel plate like this one.
It seems to have the actual Tele-Xenar formula, five elements in three groups, which is quite unlike the Xenar, which is of course a four element-three group Tessar. The Tele-Xenar is a telephoto design that seems to be capable of great compression - the reduction in physical extension vs focal length that is the purpose of telephoto design. The total physical length of the lens from iris to focal plane at infinity focus seems to be around 120mm, or a ratio of around .66, which is fairly extreme. The similar and more common Schneider 135mm f/4.5 also made for Korelle (and Exakta, etc.) is actually longer than this 180mm, probably because it is actually just a Xenar.
This was very easy to mount for SLR, because M41 is very close to M42, and it screws right in to an M42 extension tube. A 30mm tube gives it just a bit past infinity on an M42 camera, and of course on any camera with an M42 adapter. This implies that the designed back focus was around 75mm, which is in the ballpark for the 6x6 SLR for which it was made. This fix should work for any pre-war Reflex Korelle lens, in the unlikely case such a lens is found. Loose Korelle lenses are not common.
This is a very heavy lens, in spite of its small size. It is totally made of nickel-brass, in the pre-war style. The aperture mechanism is manual, this is not a preset. The lens actually opens wider than f/5.5, though the larger aperture is unmarked; I am guessing its actually an f/4 or nearly so, comparing with other 180mm's I have. It stops down to f/32 which is typical of the day. Also typical is that it is not threaded for filters. It has a clear section around the rim where a press-on filter or hood adapter was intended to go, but I didn't have one of the proper size. This is an uncoated lens, as best I can tell.
Performance is pretty much as expected - this will not win any prizes for sharpness wide open. Using it beyond f/5.5 reduces sharpness greatly, and I consider the unmarked larger aperture as unusable except for focusing. Stopped down to f/8 it is as sharp as anything on my sensor. Contrast was not terrible, but it does flare considerably in backlit situations, especially at larger apertures. Of course, I had no hood for it. Bokeh seems quite nice. All in all, a collectors item.
The bird f/5.5 -
I like Pentax DSLR's, Exaktas, M42 bodies of all kinds, strange and cheap Japanese lenses, and am dabbling in medium format/Speed Graphic work.