Zeiss Tessar Coverage

[Gordon Moat]

Greetings LF Forum,

Finally got my ancient Zeiss 21cm f4.5 mounted onto a Linhof board and onto my Shen-Hao. I did a quick look on the ground glass, and find that I run out of movements prior to running out of coverage. A search through the archives here indicates a 45º angle of coverage for a Tessar design. However, it seems that I have much more than that coverage even wide open at f4.5.

So seeing as how I have a degree in fine art, and not optics nor math, am I imagining the coverage to be larger? I used as much swing and tilt as I could, but did not exceed the coverage, even at f4.5. Is the angle of coverage actually greater than 45º or could this be a lens for 5x7 or even 8x10?


Thanks for any replies.


Ciao!

Gordon Moat
A G Studio

[Arne Croell]

Gordon, I didn't check on where you found the 45°, but that is either a typo (45 instead of 55) or refers to an Apo-Tessar process lens. The official Zeiss numbers for the f/4.5 series were 55° wide open, and 60° stopped down.

[John Kasaian]

Gordon,

Some tessars are like that. The 450 Nikkor M and the 14" Kodak Commercial Ektar that I have exhibit huge image circles, and are sharp almost to the very edges, quite unlike the usual tessars that are sharp in the center of the image circle and rapidly go to the worms the farther you stray from the straight and narrow. I have no idea why this is, but its kind of nice, isn't it?

[Gordon Moat]

Thanks for the reply Arne. I noticed your name often when I did the search, and I still have that issue of ViewCamera (July/August 2003) with your article. My thought was that I might have a process lens, since it is in barrel, and does not match any specifications in the chart with the article. So now it seems I have a regular lens, but my front filter size is much smaller than the M67x0.75 of your chart.

Anyway, 55º makes much more sense for what I am observing. Just for reference, the lens is a 21cm f4.5 with 18 bladed aperture stopping down to f45.0. The serial number listed is Nr. 1638815, with Carl Zeiss Jena on the lens. Best I can tell this is pre-WWII.

Again, thanks for the help and quick reply. Now I need to go out and photograph something with this, maybe some night exposures.

Ciao!

Gordon Moat
A G Studio

[Gordon Moat]

Gordon,

Some tessars are like that . . . . . sharp almost to the very edges, . . . . . I have no idea why this is, but its kind of nice, isn't it?

Hello John Kasaian,

Agreed on that. I am very surprised by this lens. If I would have known this, I would have made much more effort to get this lens mounted onto a board sooner. I even managed to find an aluminium Carl Zeiss Germany felt lined lens cap about a year ago . . . basically, this is my only shutter for this. Probably try some night exposures with this soon.

Ciao!

Gordon Moat
A G Studio

[Arne Croell]

Thanks for the reply Arne. I noticed your name often when I did the search, and I still have that issue of ViewCamera (July/August 2003) with your article. My thought was that I might have a process lens, since it is in barrel, and does not match any specifications in the chart with the article. So now it seems I have a regular lens, but my front filter size is much smaller than the M67x0.75 of your chart.

Anyway, 55º makes much more sense for what I am observing. Just for reference, the lens is a 21cm f4.5 with 18 bladed aperture stopping down to f45.0. The serial number listed is Nr. 1638815, with Carl Zeiss Jena on the lens. Best I can tell this is pre-WWII.

Again, thanks for the help and quick reply. Now I need to go out and photograph something with this, maybe some night exposures.

Ciao!

Gordon Moat
A G Studio

Hi Gordon, your lens is indeed pre -WWII, it was made in 1935. The design date is 1929, and thus it is the same design as most of the postwar 210mm f/4.5 Tessars, except for the coating. Barrel mounts can change over 50 years or more, the 67mm was based on some specimens I had and postwar catalogs. Most LF Tessars were sold in barrel, so this does not indicate a process lens here - and f/4.5 is not a value you usually see on process lenses.

Arne

[Ole Tjugen]

Most of the pre-war process Tessars were f:9 to f:15, and very clearly marked Apo-Tessar. The "normal" Tessars were mostly f:4.5 (in the common LF lengths) or f:6.3 (the very long ones, like my 50cm).

It's a (fairly) safe bet that a Tessar f:4.5 with a focal length between 135 and 360mm focal length will have 55 degrees coverage.

[Dan Fromm]

Ole, there were also shortish f/6.3 Tessars. For example my 130/6.3 and 150/6.3, both CZJ lenses and both made in 1912. And mid-1930s 150/6.3 that Jim Galli surprised me with. Shorter ones exist; I recently decided not to bid on a 90/6.3 CZJ Tessar of about the same vintage.

[Arne Croell]

Ole, there were also shortish f/6.3 Tessars. For example my 130/6.3 and 150/6.3, both CZJ lenses and both made in 1912. And mid-1930s 150/6.3 that Jim Galli surprised me with. Shorter ones exist; I recently decided not to bid on a 90/6.3 CZJ Tessar of about the same vintage.

Dan is right. A 135 and 210mm f/6.3 were continued after WWII, actually they were redesigns from 1947. Zeiss claimed 70° coverage for those, stopped down well I assume.

[erie patsellis]

Arne,
I have a 10.5cm tessar, that covers 4x5, I'm not sure how sharply, but covers with room to spare.


erie