ross 276mm f/16 w/a anastigmat

[voigtf64]

I have a couple of questions you wise souls maybe able to help me with.
Firstly, is this lens a protar design ? Secondly what do think the image circle
would be ? and finally what age is it ? It has been in a cupboard for years, but it
is only after following the threads on this forum that has made me wonder what I
possess. So thank you. (sorry 265mm)

[IanG]

Ross and Zeiss had an early association, Zeiss licensing Ross patented designs and vice-versa.

In the first world war Ross took over the Zeiss factory in London. I have a 151mm Ross AM (Air Ministry) wide angle which is a Protar, but because it was wartime production there's no Zeiss patent marking. The mount on mine looks very similar to yours but the glass is smaller and the lens covers 10x8 with just a little room for movements, your should have wider coverage.

The Ross wide-angle Protars are usually f16 max aperture while the Zeiss wide-angle Protars are f18. Optically they are supposed to be good lenses unfortunately mine has too many cleaning marks, while your lens looks to be ok. So date wise sometime during or after the first world war.

Ian

[voigtf64]

Thank you IanG for your informative reply, in fact it made me look further
and I also have another but this is black with a chrome ring around it,
miniscule in size , and this is 140mm f16, no hope of that covering 10x8 I
suppose, however thanks again, jw

[IanG]

I also have another but this is black with a chrome ring around it,miniscule in size , and this is 140mm f16, no hope of that covering 10x8 I
suppose
I very much doubt it, all my data on these lenses is in the UK, I've tried my 151mm on my 10"x8" Agfa Ansco and it's surprisingly easy to focus despite the f16 max aperture, it must be less than 1% of the weight of my 165mm Super Angulon and just that touch wider.

Ross made some very nice lenses, I also have an early symmetrical 300mm f8 whole plate lens which I must have bought 20 years ago intending to use it on my Wista. It's time I actually shot some film with them, I have a Packard shutter so can rig up a lens board to take them both.

Ian

[Ole Tjugen]

The sales literature for the Zeiss Protar f:18 said 110 degrees coverage, which translates to an image circle of 3x focal length. So that 140mm should cover a 420mm image circle, at least by 1890's definitions of coverage.

I've used a 150mm WA Aplanat with less stated coverage on 24x30cm film (360mm diagonal), and to my surprise it's quite acceptable for contact prints (just don't put too many details in the corners).

[shuimo]

What a nice lens! I have a zeiss version 18cm F18. Can't believe these lenses are so small but so capable. Please let me konw if you want to part with it ;)
shuimo

[voigtf64]

Ole, Thank you for your information, you wouldn,t care to come up with a figure for the image circle on the 265mm would you? I just put it on my 10x8 and can,t find an edge.
Shuimo, sorry, I am a buyer by nature and not a seller, regards jw

[Ole Tjugen]

As I said, the original specification was 110 degrees or 3x focal length. 3x265mm = 795mm.

The longer Protar 18's have slightly less coverage, and the f:16 license versions even less. But it should still be around 700mm!

So I might just be able to shift it out of coverage on my 30x40cm camera - 500mm diagonal.

[voigtf64]

Thank you for that , I now have all the information hoped for, great forum, jw.