Help Identifying Goerz Lens

[David Lindquist]

I have a Goerz Optical Co., Inc. sheet on the Low Distortion Artar dated 1/67. It comments that the external physical dimensions are the same as for the Red Dot Artar (of the same focal length.)

I have a 24 inch Red Dot Artar. The threads that mount the cell to the barrel measure 2.638" in diameter with a pitch of 30 threads per inch. Measurements were taken with my Starrett 2-3 inch micrometer and my Brown & Sharpe set of leaf type thread pitch gages. Full disclosure, I only measured the front cell, the rear would be the same.

These cells would not be a direct fit to any shutter. To shutter mount these (typically in a No. 5 Ilex Universal) Goerz machined intermediate pieces internally threaded to accept the cells, externally threaded to fit the shutter and of the proper lengths to give the correct distance between the front and rear cells.

On my 24 inch Red Dot Artar, s/n 802221, the cells are brass mounted. I don't know when Goerz switched from brass to aluminum, or for that matter if it was a one time change. I have a 9 1/2 inch Red Dot Artar, s/n 825275, whose cells are brass mounted and an 8 1/4 inch Red Dot Artar, s/n 840856, whose cells are aluminum mounted. I'm not aware of any Goerz serial number/production year lists that go above the high 700,000's.

David

 

[David Lindquist]

My 1/67 sheet describes the Low Distortion Artar as a "slightly asymmetrical" Artar type, available in the same focal lengths as the Red Dot Artar. They were designed for "a minimal distortion (less than .005% of equivalent focal length) at any required reduction ratio." Suggested applications included "military display units" (no idea what that means), micro-miniturization and "reduction of maps or other areas where low distortion and fine line definition are required..."

This sheet says they were available in either shutter or barrel mounts but my Goerz price lists only show barrel mounts. My August 1970 price list shows the 24 inch Low Distortion Artar was $1072.50 while the barrel mounted 24 inch Red Dot Artar was $607.20.

David

 

[MTGseattle]

David, thank you very much for that info. In what is typical fashion for me, I have no way to use the thing as-is. I didn't think to order a blank lens board when I learned my bid was accepted. Like money burning a hole in ones pocket, I now have a lens occupying my subconscious.
Interestingly (or not), I got a weird data sheet with this lens that is for the 14" L.D. Artar. Distortion numbers and other data that are completely out of context for me.

I really wish the Ilex #5 had 1 or 2 more shutter speeds.

 

[MTGseattle]

Here's some more rudimentary measuring; The weight of the 24" F11 LD Artar lens and mount flange (on my usps postal scale) is 2 pounds, 9 ounces.
Front cell group mount threads = 68.51mm
rear cell group mount threads = 68.70mm

Do not quote me on these. I'm sure there is a document out there somewhere that notes the exact number and thread pitch.

I do not own a thread pitch gauge. I'm going to assume I wasn't careful enough and that the front/rear mount threads are supposed to be the same.

There's been a 24" red dot artar mounted in a modern Copal #3 on ebay for a while. I'm really curious how that came about. To mount the brass one would require an approximately 10mm step-down ring and without doing that myself, I question whether that would decrease the image circle?

 

[Dan Fromm]

There's been a 24" red dot artar mounted in a modern Copal #3 on ebay for a while. I'm really curious how that came about. To mount the brass one would require an approximately 10mm step-down ring and without doing that myself, I question whether that would decrease the image circle?

Three of them today. SKGrimes says it can be done, ask Joel or Adam how.

 

[David Lindquist]

It's been my understanding that when the 24 inch Artar is mounted in a No. 3 Copal one loses 1/3 stop on the maximum aperture. All three 24" No. 3 Copal mounted Artars currently showing on ebay show f/11 on the aperture scale, One seller does comment that the maximum aperture is, in fact, f/12.5.

As far as the thread diameter goes, my 2.638" is 67.005 mm. If you and I were to sit down together and measure each other's thread diameters we might very well find we are a bit closer together in reality.

I do wonder just how SK Grimes shoe horns these in to a No. 3 Copal. Do they turn down and re-thread the cells themselves as part of the process?

David

 

[MTGseattle]

I've looked at one of the listings quite a bit (for a week or so I had myself convinced I should buy it due to the relatively low price vs. a Fujinon C 600). As near as I can tell it looks like 2-4 reduction "barrels" to get the proper threads and cell spacing fore/aft of the shutter.
I like the idea of the native Goerz aperture assembly with its many blades, but as a primarily landscape photographer, how often does dreamy, swirly, smooth, etc. Bokeh become important?

As an aside, I asked Keith Canham if I should have any concerns regarding a -/+ 3 pound lens hanging out on the front standard, and all he said was that in certain situations I may have issues with the front axis tilt staying locked tight.

 

[MTGseattle]

Update of sorts.

To mount this beast, I sourced a couple of Toyo 158mm lens boards. I then sourced two new hole saws in sizes I didn't have (more tools, Yay!)
In all of my recent reading, using hole saws in Aluminum requires very low rpm. in the case of the Bahco sample I bought 135 rpm to be exact. I have nothing that urns that slow. I'm sure I could source a new pulley and modify my drill-press to get there, but not this time.

Does anyone have any clues as to a tool that a normal person would have around that turns under 200 rpm? I could go old-school and use a bit brace I guess?
Anyway.

The Toyo lens boards are pretty thin. I don't think it would be appropriate mounting the Goerz mount ring directly to that surface. I "machined" a piece of 1/2" Baltic birch plywood that gets bolted to the inside of the Toyo board. The new hole in the Toyo board is large enough to accommodate the Goerz mount ring, while the mount ring itself gets mounted to the plywood. My version 1.0 is pretty rough, but the concept is sound. This weekend, I will tidy it up and version 2.0 should be a working item.

My other thought is to do the same thing with a Toyo recessed board which in theory would hold more of the lenses weight centered in the front standard vs completely in front of it. I need a recessed board in hand to measure the lens mounting face.

 

[MTGseattle]

One more question that I think can apply to many "modern" process lenses. My 24" Artar has an aperture assembly and a waterhouse slot. Why have both? Can anyone comment on the image quality generated by one vs the other in a lens that can use both?

 

[AnselMortensen]

Process lenses sometimes used waterhouse stops with holes of different shapes to modify the shape of halftone dots.

 

[maruti660]

That is your gem! I feel so happy just reading your posts.