Hi,
when searching through previous threads looking for information about the Xenar 3.5/15 cm lens, I found postings referring to Tessar formula and something called Type-D.
Could someone please explain what Type-D is and if all Xenar 3.5/15cm are Type-D or if there are variations...such as when did they start/stop being Type-Ds.
I recently bought one made in the mid 1940's and is hoping to use it for nice 'old looking' portraits.
Patrik,
Hartmut Thiele in "Deutsche Photooptik von A -Z", 2007, lists three F 3.5 Xenar types in ranges that may or may not include your specific focal length:
3.5 Xenar f 50>300mm with cemented group in front, introduced 1929
3.5 Xenar f 50>300mm with cemented group behind, intoduced 1934
3.5 - 4 Xenar Typ D, 105>180mm, a 3 -3 triplet, introduced 1926.
If your lens is a "normal" Xenar (cemented group behind) you might be surprised how fresh (not old) your photos will look.
Uli
Patrik, "old" looking portraits were shot on old (not aged) film and printed on old (not aged) paper. Most lenses from the '40s, really wide angle lenses excepted, shoot like modern lenses. IMO, the keys to the "old" look are emulsions and processing.
To muddy the waters a little, my 15cm f:3,5 Xenar Typ D has the cemented group in front and an air-spaced group with negative (total) focal length behind the aperture. Definitely not a 3-3 triplet, nor a Tessar.
Mid-1940's is a bit too late for the Typ D, I think.
Hi Patrik
I have a 'quote' Xenar Typ.D.f:3.5 F - 15cm, mounted in a dial set Compur shutter. The lens dates from 1926. The LVM describes it as a reverse Tessar, 2 cemented elements in front and 2 air spaced behind. A previous owner must have thought that it was a good lens as it has a nice purple coating. It is not supposed to cover more than 6x9 but I have shot 5x4 with it and putting it on the 5x7 it seems to cover that as well. I have yet to take any pix on 5x7. As Ole says I think Type Ds were only made in the 1920s. Tessars are nice lenses, have fun.
Alex
Ole,
the first Xenar series I mentioned (by quoting Thiele) has or had a cemented group in front. Would you exclude that some or all of these Xenars got a "D" after the name ( and not only the 3-3 triplet)? Or do you say, Thile is wrong here. I know him a bit and can assure you that he is quite open to correct errors. I haven't found many up to now, BTW.
As far as I know there were more triplets of this front doublet type. To mention just two: Westanar by Isco (=Schneider) and Culminar by Steinheil. Apparently the basic triplet design allowed many variations inasmuch as more importance is given to speed and definition than to covering power.
Cheers
Uli
Uli,
All I'm really certain of is that my Typ D is clearly marked as such on the outside of the front cell, and last I checked I was convinced there is a faint "internal" reflection in the front cell. From what little I know of lens making (and naming) at that time, one sample is too little to suggest corrections.
I know that the Vade Mecum also calls it a triplet, but I don't really consider the VM "authoritative" on German optics.
As an aside, would Herr Thiele possibly know anything about a Schneider Göttingen Aerotar 50cm f:5.5? Schneider know nothing, and ISCO can only confirm that the serial number corresponds to their production year 1944... It seems to be an "advanced triplet", possibly a 3+3+2, but with this many elements it's difficult to be certain.
There is a 4.5/ 500cm Aerotar listed in his book ( mentioned above); made by ISCO ( that is Schneider Göttingen) , introduced 1943, and characterized as a "Fliegerkamera". No design specs given. But as Thiele, whenever possible ,goes back to primary sources - patents, correspondence, "Firmenschriften", I'm almost certain he knows how it is built.
I too have found references to the f:4,5 Aerotar - but mine is a f:5,5.
It weighs about half a ton (3-4 kg? I don't have a balance in that range), and has a bayonet-locking yellow filter. I mat be able to mount it on a "Reisekamera", but nothing else is solid enough to support it (short of an airplane).
Ole,
my dictionary tells me: Aerotar is synonymous with aerobics.
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