View Full Version : L. Kamm London, no infos about the maker/lens

11-Nov-2010, 19:17
I found a cheap long focus lens, for which i have found absolutely no infos.
It's a L. Kamm & Co. London 17in (430mm) cylindrical lens (s/n: 59x), without an iris, and without a fitting thread.
The vendor told me that the lens has a "soft focus" character, and that probably will cover 8x10.
As you can see from the pictures, it comes with an extension tube (50mm length), whose use is not clear. My first guess was that it was probably meant to alter the distance of the two optical cells, modifying the optimization of the objective, but when i looked at the pictures with more attention, i saw that the extension tube should have two female threads, so it's very likely that the use was another.
Probably the brand engraved on the barrel comes from a vendor, and not from the actual maker of the lens, because the VadeMecum doesn't mention anything with this name. Being a UK brand, it's very likely that, if there is no reference on the VadeMecum, it was not a true lensmaker.
The barrel is perfectly cylindrical, with no traces of a rack for a focusing barrel, and with no way to attach it to a lensboard. So my personal guess is that it could have been a projection lens, as it's shaped as some modern lenses for trasparencies projectors.

The lens is still on its way, so i have no first hand infos about the optical project, but i don't think it could be a Petzval, as it's fairly small for a 17in lens. I don't know if there were Petzvals of limited speed, that would be compatible with the size of the lens, but i don't see any use for a slow projection Petzval!
The measurements are:
* front and rear elements - width 52mm
* the total length is 83mm

Any clue?

after some more googling, i found an interesting link about L. Kamm:
After all, probably my guess was not too far from truth: he made a special cine camera, and later cine projectors and graphic arts cameras.

have fun


Jim Galli
11-Nov-2010, 21:39
It could be a petzval type although a very slow one. Like 17" at f11 is a good guess. I have a similar one, a Bausch & Lomb petzval about the same size that was for some kind of projection and it is 18" f12. Make some pictures with it. It should cover an 8X10.

Steven Tribe
12-Nov-2010, 02:31
Leo Kamm's cine contraptions, or most often "parts" appear from time to time on UK e**y. This looks a lot like Busch's K (kino) projection lens series - Busch certainly provided them to other UK early cine producers. They are all Petzvals.

Steven Tribe
12-Nov-2010, 02:45
I have just checked the Busch projection lens catalogue and it matches the "W" series in terms of both diameter and focal length. They listed the following longer focal lengths - 16, 18, 20 and 25". The "K" series did not have these focal lengths and was narrower.

You can find this projection catalogue (pdf), which gives data that is illuminating for other makers products too - at cineressources.net. Easiest to enter using google with busch projection catalogue. Includes a single photographic objective too.