Mystery Lens on Ilex Dial Set Shutter

**morecfm** · 18-Jul-2017, 18:52

I got a lens with some other stuff mounted on an Ilex #4 Dial Set shutter. There are no markings on the lens cells, but they appear to be identical.

What I've been able to determine thus far:
Ilex #4 shutter from measuring.
Symmetrical design
An air gap between lenses in the cell due to two reflections when held obliquely to the eye.
About 1/4" or so between the outer surfaces of the lenses on each cell.
Lens diameter (glass) is 1 5/8"
Cell Housing diameter is 2 1/8"
Aperture scale from f/8 to f/64

From the research I've done, this could be a symmetrical double gauss design, right?

Should I be able to estimate focal length by focusing on an object at infinity and measuring the distance between the ground glass and lens board to estimate the focal length? If I'm within ten percent I'm okay with that estimate.

There is some yellowish "steel wool" like deposits of some sort near the lens cell mount between the lenses. Adhesive residue?

Also when I got it, there was only one screw holding the back of the shutter together and the back opened up breaking one of the shutter blades. Can I just measure the thickness of the material and fashion another part like it, perhaps photocopying one of the good blades and using the copy as a template? I wouldn't think there would be a source for these old parts short of finding an identical shutter. There isn't much value in this project as I could just try this lens as a barrel lens in a Speed Graphic if the focal length isn't too long. It isn't worth throwing any real money at it.

The three photos are the lens assembly, the shutter with both cells facing up, and the shutter with one cell up and one cell down.

Any information would help satisfy my curiosity.

**Dan Fromm** · 19-Jul-2017, 05:55

Air-glass interfaces cause strong reflections, glass-cement-glass interfaces cause weak reflections.

If you see only two strong reflections and no weak reflections from each cell then each cell is a singlet. Weak reflections can be very hard to see.

Look again. That grainy stuff around the periphery of the lens in y'r third picture looks like failing Canada balsam, so your lens can't be a pair of singlets. Double Gauss type? Possible, but I doubt it. Without seeing more, Rapid Rectilinear is a better guess but it is only a guess.

**Steven Tribe** · 19-Jul-2017, 06:35

+1 to RR.

Gauss designs had to compete in speed with anstigmatics and tessors. So F8 is usually a RR. Classic edge balsam oxidation syndrome!

**morecfm** · 19-Jul-2017, 07:48

Originally Posted by Dan Fromm

Air-glass interfaces cause strong reflections, glass-cement-glass interfaces cause weak reflections.

If you see only two strong reflections and no weak reflections from each cell then each cell is a singlet. Weak reflections can be very hard to see.

Look again. That grainy stuff around the periphery of the lens in y'r third picture looks like failing Canada balsam, so your lens can't be a pair of singlets. Double Gauss type? Possible, but I doubt it. Without seeing more, Rapid Rectilinear is a better guess but it is only a guess.

Dan, the second reflection is definitely weaker than the first one plus the information on the Canada balsam leads me to a cemented pair. I learn something new everyday. This information plus Steven Tribe's response suggests Rapid Rectilinear design. Now for more research on who could have made such a lens. The mystery is there are no markings on the lens cells. Now to try to date this based on the shutter and when Ilex would have produced such a shutter.

For a LF newbie like me, would the balsam issues along the edge cause any significant image issues? I kind of want to try this out at least once.

**Steven Tribe** · 19-Jul-2017, 12:47

Edge breakdown of the cement doesn't really influence the optical performance, especialy as you will be using this at around f.16. Only if the cement elsewhere has become granular or tinted is there a difference.

**Jim Galli** · 19-Jul-2017, 14:41

Looks like a very nice old 12 1/2 or 13" Rapid Rec to me. Enjoy. They are fine lenses. Companies like Wollensak and Gundlach kept them in production as price leaders long after anastigmats were the order of the day for big city pros. Many were in brass barrels with etched information that was lost when someone later liked them enough to have a machinist make barrels for a shutter. The brass barrel got trashed and the lens in shutter like you have lived on without it's original name. Good luck on making a blade. Before you drive yourself crazy, put a wanted ad for a junk box equivalent shutter that you can steal parts from. Happily, they aren't worth much. Steve Grimes gave these old Ilex's a bad rap on his site. Probably all true. They're like a Model T. We shouldn't expect them to run like a modern car. Same goes for the Wollensak Studio shutters. Some of us enjoy a Model T because it's a Model T.

**morecfm** · 19-Jul-2017, 17:33

Gentlemen,
Thank you for your kind and informative responses.

So...I'm going with Rapid Rectilinear. I measured the distance between the center of the shutter to the ground glass at about 12 inches or so.

I saw some information on similar lenses on the Camera Eccentric archive that Ilex did have a 12 1/2 inch symmetrical in a #4 shutter but the lack of marking on the lens suggests Jim Galli's thoughts. Anyway with a bum shutter I should be able to get about 13-13.5 inch extension from the old, old speed graphic so time to fashion a lens board and let 'er rip as long as there's enough distance between me and the subject.

Old things are fun to play with and make useful. I couldn't pass up a Graflex RB last year.

**morecfm** · 2-Aug-2017, 19:19

Ok, rather than open another thread, here's another lens rescue opportunity.

I got a CZJ 15cm f/4.5 Tessar with clean glass but a broken, missing parts, in pieces Prontor-Press #1 shutter. I can get a Polaroid/Tominon lens with Copal #1 shutter inexpensively to possibly salvage the lens cells. I've read that the shutter may be slightly, perhaps a fraction of a millimeter, thicker than standard shutters as well as the aperture being set back a little farther than a standard shutter. We engineering types just cannot let good stuff go to waste.

Can a Tessar accommodate a slight difference in the aperture position and possibly shutter thickness without noticeable detriment? Just thought I'd give it a try. If not, then I will look at using this lens with the existing shutter in barrel mode on my ancient Speed Graphic.

Thanks.

**Jim Galli** · 2-Aug-2017, 22:00

Avoid the 7.5cm Tominon.
The 127 f4.7 is in a usable shutter. If you measure with a caliper I'll be surprised to hear there's any extra barrel length. All of the 150 CZJ 4.5's I've owned were forgettable. But the Polaroid shutter will work for 210 and 240 mm G-Claron in barrel so you'll end up with those sooner or later. Caution: Some of the Tominon Copals have no aperture. They're useless. Make sure you get one with a visible aperture scale. If the focal plane shutter is working in the Speedy, why bother with another shutter?