Carl Zeiss Jena Tessar 4.5/135 in Compur dial set shutter
The famous Tessar, Zeiss' million seller, patented in 1902 by Dr. Paul Rudolph, improved 1906/07 by Ernst Wandersleb and accomplished by Willy Merté from 1927 to 1930. Literally accomplished, the Tessars for large format photography were produced for decades without modifications, besides coating, until the 1980ies. The 1.000.000th Zeiss lens was made in Sept. 1929, this one is number 1.002.052. Still, it is not clear if this copy here is one of those redesigns by Merté.
It is without visible scratches, the clearest uncoated lens I have. The bezels are completely out of brass, you can easily part the first two elements. On the bezel of the rear part (on the backside of the shutter) "2052" is imprinted, to exclude confusions.
The lens is related to the 9x12 cm film format and has an angle of view of 57°. For this format Zeiss also offered a 4.5/150 with 53°.
The shutter bears the serial number 230199. A list on camerawiki states, that this shutter was produced in 1914 or earlier, but I have my doubts. First, it doesn't match with the age of the lens. Second, it has that "Zeiss Ikon" name plate, and Zeiss Ikon was founded in 1926. Anyway, I found this type of shutter on a C. P. Goerz Tenax camera from 1911. Amazing, that a more than 100 year old device is still fully usable today. A contemporary camera for this shutter/lens combination here could be a Zeiss Ikon Adoro 230/7 9x12 plate camera from 1929. I also found out, that early shutters have only the letters Z, D and M on the mode dial. The international equivalents T, B and I were added later.
My shutter required some service, it didn't close completely in mode B and the 1 s needed about 5 s. The problem with B was solved very quickly: the spring, which closes the shutter blades, slipped out of its correct position. The cleaning of the shutter blades was furthermore helpful. The cleaning of the escapement speeded up the second to 1.3 s. With some clock oil given to the axises of the tooth wheels, the second was more or less achieved. I measured it by recording the noise with a digital audio recorder and checking the sound file in an audio editor. Intriguingly I noticed, that the shutter reached his full speed not until a third of the time. And I thought of how they measured the speeds in 1911.
In the picture above you can see the opened shutter; with the two marked pins the shutter speed is controlled. With A the speed is set, whereat 1 and 1/25, 1/2 and 1/50, 1/5 and 1/100, 1/10 and 1/200 are sharing the same position. With B the escapement is activated for the slow speeds.
The aperture scale has already useful values, not odd ones like f/9 or f/12.5. BTW, the 10 aperture blades consist of lacquered paper, so I found it to dangerous to clean them.
The shutter has the size #1, so the thread on the rear side is 39 x 0.75 mm. As a makeshift you can carefully attach it onto a bellows with M39 (39 x 1 mm) adapter. So, my first test shots on a full frame DSLR really impressed me. Okay, you are using less than 10% of the intended film format, so vignetting and distortion are no item. Also the decrease of sharpness to the corner was low, even at f/4.5. Due to the lack of a coating, the contrast obviosly was low. This changed abruptly when stopping down to e.g. f/11, you have very good sharpness and even brilliance then. What impressed me most, was the absence of chromatic aberrations, I just couldn't discern them. In 1929 that lens had to be sensational. But I noticed a flaw, you find seldom on modern lenses: at small distances there is a "focus-shift", the focus changes a little bit when stopping down.
