Mystery brass lens

Raphael · Jun 6, 2013

Hi all,

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 !

Best regards,

Raphael

removed account4 · Jun 6, 2013

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!
- john

Two23 · Jun 6, 2013

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

Ian Grant · Jun 7, 2013

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.

Ian

smieglitz · Jun 7, 2013

Look along the frosted edge of the glass elements inside the housing. Sometimes the maker added a signature, date, and location there.

Raphael · Jun 8, 2013

Hi all,

jnanian said:
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!
- john

Bonjour John

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 : Dead Link Removed
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.

Best regards,

Raphael

Dan Fromm · Jun 8, 2013

Berthiot, peut-etre?

removed account4 · Jun 9, 2013

could it be a TESSAR lens ?

http://en.wikipedia.org/wiki/Tessar

they have a cemented group and a airspaced one

shutterfinger · Jun 9, 2013

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.

Raphael · Jun 10, 2013

Hi all,

Dan Fromm said:
Berthiot, peut-etre?

Hello Mr 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 !

Cheers,

Raphael

Two23 · Jun 10, 2013

My thinking is it's a Petzval that someone tried to clean and put it back together out of order.

Kent in SD

removed account4 · Jun 10, 2013

Raphael said:
Hi all,

Hello Mr 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 :
View attachment 69917

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 !

Cheers,

Raphael

maybe it is a reversed tessar because light travels through the lens
opposite with a camera than when projected ?

looks like a fun objectif

john

Whiteymorange · Jun 10, 2013

I'd vote for it being a modified Petzval. As this page from the 1890 Ben. French Catalogue (found Dead Link Removed, thanks to Dan Colucci) clearly states, photographers have pernicious habits of taking lenses apart and screwing them up! There were many variations on the design tried by lens-makers during the 19th century. [video]http://www.antiquecameras.net/petzvallens.html[/video] has extensive material if you're interested.

Raphael · Jun 12, 2013

jnanian said:
maybe it is a reversed tessar because light travels through the lens
opposite with a camera than when projected ?

looks like a fun objectif

john

Hi John,

Your question is an interesting one, and maybe any optics pundits around can answer it ?
As the Tessar is not a symmetrical design, should it be reversed if the lens is used as a projection lens ? Logicaly I would think the answer is yes, but is this sure ?

@Whiteymorange, thanks for your reply.

I discovered recently the antiquecamera.net website, it's a goldmine !
The design of my lens looks like a little the Dallmeyer portrait lens, as described on the petzvallens page. However i am inclining too for a mistakenly remounted Petzval. The fact that this lens was very clean for its age when I found it is aiming me this way.

A check procedure will be to mount it on a camera and see what I get on the groundglass, but I haven't the appropriate lens board for now.

Best regards,

Raphael

Mystery brass lens

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