Another Contax Tessar question

Before WW2 the Contax 50mm Tessar was f:2.8. After the war it was

f:3.5, which seems strange considering that for their other cameras

such as the Contaflex it was f:2.8. I'd be interested in any

discussion of why this was done. Incidentally, are the M42 mount

coated Carl Zeiss Jena Tessars as good as the Zeiss Opton glass?

Thanks, Bill.

The f2.8 Tessar had always been somewhat of a compromise. It had flopped most notoriously with the Postwar Rolleiflex model A and was always somewhat soft at 2.8.

 

Postwar Carl Zeiss (West German) probably got this one right, it offered the excellent Sonnars all the way to f1.5 and the f3.5 Tessar which excelled when available light was not an issue. Some believe the f3.5 tessar is the the best normal lens out there for the Contax RF system.

Most users chose the Sonnar lenses and thus the postwar f3.5 is quite a rarity.

2,8 with the glass available before WWII had been overstretching the Tessar design a bit; the 2,0 Sonnar was much better at 2,8. Zeiss Jena and Zeiss Oberkochen independently redesigned the Tessar later - must have been in the late fifties or early sixties - when new glass types were available, so late post war 2,8 Tessars are much better than pre war Tessars. Tessars never were in high demand with Contax users; those few who could afford Contaxes had the money to buy the Sonnar with it, and did it.

 

Early coated CZJ 2,8 Tessars are not as good as early 3,5 Tessars; after the redesign the 2,8 version became quite good. But don't ask me when the change took place.

FYI, many of the pre-WWII 5cm Tessars in Contax mount (& for the Super Nettel & other Contax cousins) had a max. aperture of f/3.5, too. I believe in their "speed" war w/Leitz, etc., Zeiss Ikon wanted to be able to market the Tessars as f/2.8 lenses, i.e., they were faster than Leitz's f/3.5 Elmars. This may have been most effective when the f/1.5 & f/2 Sonnars were still considered super-pricey specialty lenses used only by pros & rich amateurs. Of course, anyone who's used Tessar-formula lenses (whether the Contax version or the 8cm version of the Super Ikonta B, etc.) knows that they don't exactly perform their best @ f/2.8 even when they've been manufactured to have that max. aperture. After WWII, I think Zeiss Ikon decided to give up the pretense of f/2.8 & go w/f/3.5 Tessars; anyone who really needed/wanted speed would go for a f/2 or f/1.5 Sonnar, anyway.

 

As to the M42 mount CZJ Tessars, I don't see why they wouldn't be optically as good as (or @ least very close in quality to) Zeiss-Opton or Carl Zeiss glass, as the post-WWII CZJ Tessars in Contax mount are as good as the Zeiss-Opton & Carl Zeiss Tessars (although AFAIK, the post-WWII CZJs were never made in the more durable & reliable rigid mount like their W. German competition).

I don't know the exact date of the "recomputed' f/2.8 Tessars that went into the late Contaflexes, but since the Contax only lasted until 1962 and was fading from about 1954 on, I'd guess the improved f/2.8s came too late for it. Too bad; a late recomputed Tessar in a collapsible mount would have been a really nice lens for a IIa.

 

:)=

This f/2.8 Tessar doesn't seem to get the flak like its predecessors:

 

http://www.contaxcameras.co.uk/slr/slrmanlenses/tessar45.asp

OK, according to my copy of John Keesing's "Contax Rangefinder Lenses 1932-1962," the "5cm f2.8 Tessar could be described as a stretched version of the 5cm f3.5 Tessar, & was offered a for sale a few months after that lens came on the market [1932 for f/2.8, 1931 for f/3.5]. The enlarged aperture caused a slight decrease in resolution & an equally slight increase in edge illumination. At least 2 optical designs were used & a larger rear element was introduced in 1934." Except for a few f/2.8's made in 1949 by CZJ after WWII, all postwar 50mm Tessars in Contax mount, E. & W. German, have a max. aperture of f/3.5.

The Opton Tessar was the west German late Tessar design and is likely the better of the bunch. The price is also quite a lot higher. Is it worth it? Probably not.

As noted, there were two versions of the Contax Tessar: both were collapsible. I have the f/2.8 version. A nice lens overall. Contrast is somewhat low, but that might have more to do with the fact that it's not coated.

 

Postwar, Carl Zeiss produced f/2.8 Tessars for the Ikonta, Contina, Contess and Contaflex (all using the same lens), later rigid-front Contessas, the Super Ikonta B and the Rolleiflex 2.8A (didn't enjoy as much success as other models).

 

I would think that the East German Jena Tessar would compare favorably with the West German Tessar.