Mystery Lens Identification

[Punkinhed7]

Got this lens in a lot of stuff recently and am having the darndest time figuring out what it is.

I've poured over the lens with a loupe and can't find a single marking on it anywhere--either cell--to indicate the make. What piqued my interest is that the coverage appears to be pretty large for such a small lens. It appears to easily cover 8x10, possibly 11x14, wide open.

Came mounted in an old dial-set Compur shutter which, by the serial number, dates to ~1914. Slightly oddball size on the shutter as well:both front and rear lens mounts have ~35mm openings--otherwise it appears to be a #1. F/stops are marked "4.5, 6.3, 9, 12.6, 18, 25, 36." No idea if it's original to lens. Hood in the last picture was on the lens as well.

Any help at all in figuring out what I've got here would be much appreciated. Thanks in advance

 

[Punkinhed7]

Update: measured the focal length and it's around 170-180mm

 

[Ian Grant]

The shutter is a Dial set Compur 1a, a 180mm Dagor covers 10x8 stopped right down it might illuminate a bit more. Coverage is acceptable sharpness (as deemed by the manufacturer) rather than illumination

I'm not suggesting it is a Dagor the maximum aperture would be f6.8, there was a 180mm f4.5 Dogmar but that only has 60º coverage stopped down, and a Tessar doesn't have that coverage either.

You need to determine how many elements and their configuration, I'm assuming it;s symmetrical.

Ian

 

[Ian Grant]

OK, a quick thought, it's almost certainly not the original shutter. As you included a scale in the image of both front/rear cells and estimate the FL to be 170-180mm it's possible to do a rough calculation of the maximum aperture which would be between f7.7 if 170mm to maybe f9 at 180mm.

I have a 16.5cm f5.3 CZJ Tessarwhich is in the same size Compur (Dial set) 1a shutter and the glass in the front element is right to the edge of the tube (Deckel's term for barrel). So there's no way you could get a slightly longer FL f4.5 lens in the shutter.

cameraeccentric seem to be off-line (hosting doesn't expire until this Autumn), that would be a good place to look at possible manufacturers. Look at early wide angle lenses possibly Meyer (theirs was a dialyte), WA Dagors, early Angulons (WA DAgor design). It looks like two rear cells to me but with a Symmetrical design that wouldn't matter if they matched.

If Dan Fromm see's this thread he can give you far more clues as to where/what to look for.

Ian

 

[Punkinhed7]

Well, for what it's worth I have a more accurate measurement of the entrance pupil now that I'm fairly confident in: ~24-24.5mm.

I also repeated my focal length measurements using the method of measuring the distance between the lens focused at infinity and focused on something with 1:1 magnification...but my eyesight isn't wonderful and I had a bit of trouble being certain of exact focus on the macro setup. I did it twice and got 165mm the first time and 177mm the second : (

I've been pretty bummed that cameraeccentric seems to be down this week--tried to visit it on multiple occasions but still not dice. Hopefully it's not gone for good.

Re: the possibility of Dagor...there were 4 dagors and a syntor in this lot so I wouldn't be terribly shocked. Why no markings though?

Also, the point where the aperture blades in the shutter coincide with the circumference of the rear lens element is exactly at the 6.8 mark on the scale, if that means anything.

 

[AgX]

Any idea why the lens is unmarkerd?

 

[Ian Grant]

Well if we assume 165mm and 24.25mm entrance pupil that would be an f6.8 lens. One explanation of no markings could be these cells were once in a brass barrel before being mounted in that shutter. The aperture scale won't match the lens.

Ian.