Know anything about this J.H. Dallmeyer Lens?

[Ethan]

Hello,

I was at a gathering of extended family today, and as it started to wind down, we decided to take a portrait of everyone with my graphic view 4x5. When I took the camera out, my grandmother's cousin, who was hosting the event, says something along the line of "hey, we have a camera like that." Her Husband didn't think they did, but she insisted that there was "one of those old ones that looks like an accordion" sitting in the attic of their barn. He still didn't remember it, but after we took the portrait, she brought me up to the barn attic, and low and behold among old washer boards, tube radios, and other antiques, was an old view camera. The camera itself doesn't have any markings from what I can tell, so I've asked about that in the camera sub forum, but the lens is a brass barrel lens labeled "J.H. Dallmeyer / Iris Diaphragm." Most Dallmeyer lenses I have seen have the word "patent," "London," or some number on them, but asides from the name, the only other markings I can see on this lens are the aperture markings of 7.5, 10, 25, 50, 100. Mounted on the camera, it has a focal length of around 10.5 to 11 inches, and covers 8x10 with movements when wide open. It also has a screw on lens hood which appears to be original, but is banged up. I haven't been able to find any information on it, and I'm not very familiar with old barrel lenses, so I was wondering, do any of you recognize this lens? Photos posted below.

Thanks,
Ethan

[Ethan]

[Mark Sawyer]

From the aperture scale numbers, (which I'm guessing are a non-standardized progression of the standard f/stop scale, but could be the Uniform System or some other scale), I'd say it's a rapid rectilinear. Any hints of cement failure at the edges of the rear element?

[Ethan]

From the aperture scale numbers, (which I'm guessing are a non-standardized progression of the standard f/stop scale, but could be the Uniform System or some other scale), I'd say it's a rapid rectilinear. Any hints of cement failure at the edges of the rear element?

Thanks! None that I can see, there is a small amount of fungus on it though

[Two23]

You can date the lens by the serial number. I'm guessing somewhere around 1900.


Kent in SD

[Ethan]

You can date the lens by the serial number. I'm guessing somewhere around 1900.


Kent in SD

That’s what I’ve heard, but I don’t see any serial numbers on it. Where are they usually found?

[Steven Tribe]

This, I think, is unique!!

The only reason for the lack of a serial number and the "Iris diaphragm" label that I can think of, is that it is a shop display item which shows the "new" iris version of the Dallmeyer RR. As opposed to the original Waterhouse slot version.

We know that 1/2 lenses were sometimes created (from abandoned glass) for demo purposes - and these were (perhaps?) without the right engravings and a serial number as well?

[Ethan]

Very interesting, if it was a display lens used to showcase the “new” iris aperture, does anyone know around what year that would place it? I read that Rapid Rectilinear lenses were made from 1866 to around 1890, but does anyone know when they introduced the more modern aperture?

[purplecloud]

it may also be a contemporary counterfeit

[Ethan]

Are there many counterfeits out there? I’m doubtful that this is one, both because of where I got it from, and from it’s condition, but do counterfeits of lenses from this era exist?