Mystery brass lens
I don't know if it's the right forum, but I would ask help to you, LF brass lenses pundits and photo history exegetes.
Can someone can tell me if s/he know who is the maker/brand of this old camera brass lens ?
Bought on impulse at an Antique fair, the seller didn't know much about it.
and the only visible brand or logo, under the rack and pinion focuser :
I believe this is a cursive L and C and a star...
Thanks for reading !
salut raphael !
i am clueless, but usually when i see rack + pinion i think .. projection pretzel
i'm sure i am wrong, i can't even spell it right !
if you unscrew the front + rear elements, can you tell how many cells / lens groups there are ?
bonne chance avec votre mystère!
This likely is a Petzval, but it's not a projection lens. Note that it has a slot for Waterhouse stops. I think it's missing it's lens hood. If you unscrew the front lens group it should be a cement doublet (2 lenses joined together.) The rear should be two single elements with a space between them. If the rear element looks like the front ones, then this is a rapid rectilinear lens. I'm going to take a guess that this lens covers quarter plate.
Kent in SD
Some Petzvals sold with projectors etc have a slot for water house stops, I have one. This was because the R-R's largely killed off sales of Petzvals as taking lenses and often remaining stocks were bought by manufacturers of Lantern slde projectors.
Presumably it's a French lens and I'm not familiar with French manufacturers, I bought a small R-R at a antique/Flea market two weeks ago, made in Paris but can't decipher the makers name.
Look along the frosted edge of the glass elements inside the housing. Sometimes the maker added a signature, date, and location there.
Bonjour John :)
Originally Posted by jnanian
Thanks for your kind reply. There are effectively 4 lenses in two groups at rear and front, and I was thinking about a Petzval lens (or a Pretzel ;)), the front group is effectively a cemented group.
However, I am a little puzzled with the rear group, which is effectively an air spaced doublet, but it doesn't really match the original Petzval design, as described here : http://www.antiquecameras.net/petzvallens.html
Either this is a Petzval design variant (not Rectilinear, as long as I can tell), or someone reversed the rear group after dismantling it.
@Kent : thanks for your reply, my thinking followed exactly your message, the slot for waterhouse stops designed a taking rather a projection lense, but Ian tell us that was not always true.
@Ian, @Smieglitz : I can now confirm it is actually a French lens, or at least a lens with french glasses, as I followed the suggestion of Smieglitz, and looked the elements edges, and found a signature at two places ! Just an handwriten name : "Berthier". It's rather a stunning thing to found such "message" on a thing probably more than a century old...
But Berthier don't seems to have been a well known optics makers, I found nothing on it, and still don't know the lens brand.
Many thanks again for your replies.
could it be a TESSAR lens ?
they have a cemented group and a airspaced one
Under higher magnification, largest photo the site produces, and increasing the contrast the logo appears to be double struck and is possibly LB not LC with the front edge of the B not there. LB = Lacour-Berthiot.
Hello Mr Fromm,
Originally Posted by Dan Fromm
Glad to see you in this thread !
That's the first name which came in my mind when seeing the handwriting, however, IMHO (and I also asked to the Lady-to-my-side as second opinion), it's Berthier, or maybe Berthiès :
BTW, I just read your articles series about "Unlikely lenses on Speed Graphics" with great interest :)
@John : Yes, it's look a little a Tessar, but reversed, as the cemented doublet is in front :)
Trying to make things clearer, if I can make a crude chart with ASCII art, it would likes this :
------------> (|| ))I|)
Incoming rays, Front group, rear group
Front group : cemented doublet (not sure if the last surface is actually plan)
Rear group : Concave-Convex thick lens, a spacer ring (symbolized by the I) about 5mm thick, and thin plan-convex lens (not sure again if it's really plan).
@shutterfinger : thanks for your reply, it's hard to tell, but maybe it's effectively a "B". Do you know if Lacour-Berthiot ever used this kind of monogram with the star ?
Thanks again to you all !