Need to identify brass barrel lens

spoolman · May 8, 2019

I've been given this lens to try and identify who the manufacturer is and any other information about it. Images are attached.

Thanks in advance,

Doug

Ian Grant · May 8, 2019

Does it have a Aperture diaphragm ? Have you tried it against a white wall etc to check its FL ?

It has a vaguely telephoto look.

Ian

spoolman · May 8, 2019

Ian Grant said:
Does it have a Aperture diaphragm ? Have you tried it against a white wall etc to check its FL ?

It has a vaguely telephoto look.

Ian

Hello Ian: it does not have an aperture and I'm not familiar with the method of establishing the focal length of the lens.

Doug

Paul Manuell · May 8, 2019

It's got a Petzvel type look to it, not that I'm saying that's what it actually is mind.

bdial · May 8, 2019

spoolman said:
Hello Ian: it does not have an aperture and I'm not familiar with the method of establishing the focal length of the lens.

Doug

Hold a white card behind it with it pointed out a window or doorway, move the lens or card or both until you can focus an image on the card. Or focus the image on whatever wall is opposite the window/door. The farther away whatever objects you're focusing, the more accurate the measurement will be, but for estimation purposes, extreme accuracy isn't needed.
The distance between roughly the fore and aft center of the lens and the card is the focal length. The exact focal length is measured from the lens's nodal point, which is usually at the aperture (if it has one), otherwise the center is close enough for making a rough estimate.

spoolman · May 8, 2019

bdial said:
Hold a white card behind it with it pointed out a window or doorway, move the lens or card or both until you can focus an image on the card. Or focus the image on whatever wall is opposite the window/door. The farther away whatever objects you're focusing, the more accurate the measurement will be, but for estimation purposes, extreme accuracy isn't needed.
The distance between roughly the fore and aft center of the lens and the card is the focal length. The exact focal length is measured from the lens's nodal point, which is usually at the aperture (if it has one), otherwise the center is close enough for making a rough estimate.

Thanks for explaining that. Upon examining the lens closer, I found that the portion of the lens that is covered in black leather can be moved in and out and the back of the lens is threaded and the size of the thread is 32mm.

Doug

BAC1967 · May 8, 2019

It looks like a magic lantern projector lens.

cowanw · May 8, 2019

I have seen leather like that on a Dallmeyer Dallon and they seem to come in wonky version, but they are usually heavily engraved. I wonder if the mid section is original; very different brass from the front and back.

Need to identify brass barrel lens

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