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big_ben_blue
30-Apr-2008, 19:13
I got these two brass lenses: one is a JC Somerville St. Louis #6 and the other a 3D 8x10 portrait. The 3D has a "France" engraving on it. Both are cut for stops. Does anyone know anything about this lens manufacturer? I can't find anything about them.

CCHarrison
1-May-2008, 02:32
Somerville was a photographic dealer out of St Louis - not a maker of lenses.... so lenses were made by someone else and Somerville put his name on them which was commonplace in the late 1870's on....

Dan
www.antiquecameras.net

big_ben_blue
1-May-2008, 09:27
Basically the same practice that H.A. Hyatt was also doing?
That begs the question from whom Somerville bought their lenses. The 3D has the word "France" engraved in "small print". What puzzles me is the arrangement of the elements. The cemented double is in the back, and the airspaced group in the front. Should it not be the other way around (although reversing the groups seems to reduce the focal length down to something like a couple of inches)? I am a little confused.
Attached is a pic of the two lenses.

Gene McCluney
1-May-2008, 10:48
Just a note regarding vintage brass lenses. You cannot assume that the lens elements are correct, or even installed in the correct end of the tube (if they are both threaded the same). You have to do research. I'll go out on a limb here and speculate that you could assume that "any" vintage brass lens cut for stops, and with a barrel tube length as in your picture is either a Petsval or Rapid Rectilinear in design. If you know the design of these 2 styles of lenses, then you can determine if the correct lens groups are present, and installed in the correct positions. In the 100+ years since these lenses were made, who knows how many children have unscrewed the front and back groups and screwed them back in, possibly wrong.

There were literally hundreds of "dealers" or "jobbers" that marketed lenses under their own name. There were far fewer actual manufacturers of lenses. AFAIK, all the major optical houses engaged in private labeling of lenses.

big_ben_blue
1-May-2008, 11:26
Just a note regarding vintage brass lenses. You cannot assume that the lens elements are correct, or even installed in the correct end of the tube (if they are both threaded the same). You have to do research. I'll go out on a limb here and speculate that you could assume that "any" vintage brass lens cut for stops, and with a barrel tube length as in your picture is either a Petsval or Rapid Rectilinear in design. If you know the design of these 2 styles of lenses, then you can determine if the correct lens groups are present, and installed in the correct positions. In the 100+ years since these lenses were made, who knows how many children have unscrewed the front and back groups and screwed them back in, possibly wrong.

There were literally hundreds of "dealers" or "jobbers" that marketed lenses under their own name. There were far fewer actual manufacturers of lenses. AFAIK, all the major optical houses engaged in private labeling of lenses.

The #6 is a plain vanilla RR, big but utterly unexciting. The 3D OTOH leaves me headscratching. The sleeve of the backgroup is blackend, so it's sitting in the right place. And with the current "reversed" Petzval arrangement, it has about the right focal length and image circle too. Putting the groups into a proper Petzval arrangement reduces the focal length to about 2" past the rear element with a minute image circle (barely covering 2 1/4"). Something is going on, and I am contemplating if the airspaced elements might be set incorrectly in their sleeve.

Would be nice to find out the actual manufacturers too; might be a longshot into the dark though.

Gene McCluney
3-May-2008, 19:42
It is also possible that the "petzval-like" lens you have has incorrect front and back lens elements. I have experienced this myself from a lens purchase on a popular auction site. In my case, the lens doesn't focus at all!! But the lens groups screw in very nicely into the barrel.

big_ben_blue
6-May-2008, 18:00
It is also possible that the "petzval-like" lens you have has incorrect front and back lens elements. I have experienced this myself from a lens purchase on a popular auction site. In my case, the lens doesn't focus at all!! But the lens groups screw in very nicely into the barrel.

Thankfully all the elements in my lens belonged to the same lens (each element carried a matching number). I managed to find out where things went wrong - some previous owner had decided to mount all but a single lens element into the back group :eek:. The arrangement is now back in a standard Petzval arrangement and it appears to work. I am just not a 100% sure about the orientation of the back elements, if they follow the standard Petzvals or the flipped-around Dallmeyer design.