What are the grades of Optical Glass?

Ian Grant · Nov 23, 2016

The UK lens makers relied on specialist optical glass from Germany until WWI, and this caused major problems during the war. As a result Pilkington Glass were encourage to produce specialist optical glasses, these aren't the actual glasses used for elements rather the specialist glasses chosen to blend to make different optical glasses.

Pilkington's supplied most of the highly specialist glass used by Japanese optical glass manufacturers and they were taken over by a Japanese company in 2006.

Ian

DREW WILEY · Nov 28, 2016

For the right price, I know people here in town that will make you a lens which makes any conventional user camera lens on earth look like it was
made out of reconsolidated cast jelly-bean paste. Just bring along your NASA or NSA credit card with no spending cap.

chip j · Nov 28, 2016

I think they would farm it out to Zeiss.

Dan Fromm · Nov 28, 2016

Why farm work out to Zits or Lice when we have world class optical shops here in the US? Understand, you and I aren't in their market.

chip j · Nov 28, 2016

Dan Fromm said:
Why farm work out to Zits or Lice when we have world class optical shops here in the US? Understand, you and I aren't in their market.

Those names ARE funny.

DREW WILEY · Nov 28, 2016

Zeiss???? Which Zeiss lenses, the ones made in Japan, or Malaysia, or made in Eastern Germany back when the losses were subsidized by the Communist system? I'd love to own an old Zeiss research microsope like I used in college, but more for the precise machining than the lenses. Yeah, their microscope were top quality back then; but that was back then. As for Coke versus Pepsi bottles - neither. The best lenses are made from soda bottles which originally contained carbonated chocolate milk. Remember that awful stuff?

DREW WILEY · Nov 28, 2016

Well, the chocolate soda in the in big water cooler wasn't half as bad as the three dollar a gallon-jug fortified wine on the shelf above. Then there
were the kids who bought Vitalis hair gel and drank that before school instead. And remember Geritol, and how it made you "feel better fast".
Fortunately, I stuck with root beer.

EdColorado · Nov 28, 2016

I don't know what the big deal is about specialized glass, I've a cabinet full of the stuff.

There's the glass for beer, the glass for bourbon, the one for margaritas (with the cool cactus plant stem), the one for martini's....

AgX · Nov 28, 2016

DREW WILEY said:
Which Zeiss lenses, the ones made in Japan, or Malaysia, or made in Eastern Germany back when the losses were subsidized by the Communist system?

No GDR manufacturer made losses in export.
If you refer to "losses" concerning the exchange rates, these were not only dealt with the export agency but also were only virtual, as the state needed western currency and by this benefitted from these exports.

You are comparing manufacturers embedded in completely different economic systems at that borderline of inter-system trade.
This also means that a comparison based on item-based costs fails.

Alan Gales · Nov 28, 2016

chip j said:
There's the lowest grade-no brilliance; the next one up (Series One, Sigma, some Tokins & Tamron)-some brilliane; then there's full brillance-Nikon & Canon; at the top is glow and sparkle-Leitz and Zeiss. At least that's been my experience. (w/older lenses)[/QUOTE

How would you describe a Dagor or Heliar lens? Maybe the Cat's meow?

My Kodak Portrait lens definitely has a lot more glow than a Leitz or Zeiss as long as I don't stop it down too far.

chip j · Nov 28, 2016

I only know 35mm lenses.

Dan Fromm · Nov 29, 2016

DREW WILEY · Nov 29, 2016

Dagors were a design, and not a brand. My own Dagors were all made by Kern in Switzerland. What is 35mm? I don't regard Dagors as a cat's meow. To elaborate, I got woken up last night by repetitive cat's meows. When that doesn't work, they scratch on the bedroom door; and when they can get in, one of them will tickle my nose with his whiskers to make me get up and feed him. Then there were about six cat's ass trophies (catastrophies) to deal with in the litter box last nite. So really, I'd prefer Dagors to be compared with something else.

Ian Grant · Nov 29, 2016

Drew, Dagor or rather Doppel Anastigmat Series II tlenses were a design and also a "Dagor" was Brand name of CP Goerz, Berlin and the US off-shoot Goerz Am Opt later and used for this range of lenses.

Schneider acquired the "Dagor" brand name and rights to the designs when they bought Goerz Am Opt from the previous owner, Zeiss also have the rights to the design through the merger of CP Geoerz, berlin, inti Zeiss Ikon in 1926.

Ian

Alan Gales · Nov 29, 2016

DREW WILEY said:
Dagors were a design, and not a brand. My own Dagors were all made by Kern in Switzerland. What is 35mm? I don't regard Dagors as a cat's meow. To elaborate, I got woken up last night by repetitive cat's meows. When that doesn't work, they scratch on the bedroom door; and when they can get in, one of them will tickle my nose with his whiskers to make me get up and feed him. Then there were about six cat's ass trophies (catastrophies) to deal with in the litter box last nite. So really, I'd prefer Dagors to be compared with something else.

Yeah, a lot of Dagors were made by Goertz. Your Kerns are supposed to be sharper. I'd love to try a 14" Goertz Dagor but they are pricey. I do like my 14" Commercial Ektar.

We don't have cats or dogs. Kids were enough work. Our daughter moved to an apartment in Rolla last semester to attend the college so no more kids. It sure is quiot around here.

Ian Grant · Nov 29, 2016

Alan Gales said:
Yeah, a lot of Dagors were made by Wollensak. Your Kerns are supposed to be sharper. I'd love to try a 14" Wollensak Dagor but they are pricey. I do like my 14" Commercial Ektar. .

You need to check your facts Wollensak never made Dagors, some Goerz Am Opt Dagors were sold in Wollensak shutters though.

Ian

Alan Gales · Nov 29, 2016

Ian Grant said:
You need to check your facts Wollensak never made Dagors, some Goerz Am Opt Dagors were sold in Wollensak shutters though.

Ian

I can't get away with anything around APUG. As soon as I posted that I reread it and realized I made a mental fart so it's corrected. Thanks, Ian!

Alan Gales · Nov 29, 2016

chip j said:
I only know 35mm lenses.

I was just messin' with ya!

DREW WILEY · Nov 29, 2016

Ian, you are correct; but the general classification of a dagor lens as a double cemented triplet passed into generic usage long long ago. For all
practical purposes, more than one company made them, and the last of the Schneiders were made by Kern.

Nodda Duma · Nov 29, 2016

Alan Gales said:
Yeah, a lot of Dagors were made by Goertz. Your Kerns are supposed to be sharper. I'd love to try a 14" Goertz Dagor but they are pricey. I do like my 14" Commercial Ektar.

We don't have cats or dogs. Kids were enough work. Our daughter moved to an apartment in Rolla last semester to attend the college so no more kids. It sure is quiot around here.

Rolla is a great school. Got my Bachelor's and Master's there

Ian Grant · Nov 29, 2016

DREW WILEY said:
Ian, you are correct; but the general classification of a dagor lens as a double cemented triplet passed into generic usage long long ago. For all practical purposes, more than one company made them, and the last of the Schneiders were made by Kern.

There's no generic Dagors, the Schneider Dagors made by Kern are genuine as they held the rights to make them. No other companies knew the exact glasses used and the intricacies of the optical design. So in practical terms only Goerz in Berlin and later CZJ, and Goerz Am Opt and then Schneider and their then Kern susidiary have ever made Dagors.

That's simplistic though as Ross made Dagors in the UK, and along with a few other other companies in other countries, made them under licence before WWI but they weren't clones/generic, they were genuine Dagors. The same went for Tessar lenses, made by B&L in the US, Ross in the UK etc, and for a very short period Zeiss, Mill Hill, London (the factory was given to Ross in WWI by the UK Government).

Ian

Alan Gales · Nov 29, 2016

Nodda Duma said:
Rolla is a great school. Got my Bachelor's and Master's there

It sure is. I have a cousin who graduated from Rolla. So did his wife. They met in church while attending school there.

I know you are a lens designer. What was your major in college?

My daughter is studying electrical and computer engineering.

Dan Fromm · Nov 29, 2016

Ian Grant said:
There's no generic Dagors, the Schneider Dagors made by Kern are genuine as they held the rights to make them. No other companies knew the exact glasses used and the intricacies of the optical design. So in practical terms only Goerz in Berlin and later CZJ, and Goerz Am Opt and then Schneider and their then Kern susidiary have ever made Dagors.

Ian, Goerz patented the Dagor. The patents contain prescriptions that specified the glasses, elements' radii, thicknesses and spacing. There have no doubt been redesigns afterwards that weren't patented but Boyer seems to have made Beryls to Goerz' patents. Not forever, Beryls were also patented.

Since you brought Tessars up, after the original Zeiss patent expired other makers were able to copy the lenses perfectly. Also to improve on them by using newer glasses.

Thing is, many, not all, ancient lenses that were in production for decades were periodically recomputed. There's not one f/6.3 Tessar design. There are several, and more for the faster Tessar types. Trade names aren't prescriptions.

Nodda Duma · Nov 29, 2016

Alan Gales said:
It sure is. I have a cousin who graduated from Rolla. So did his wife. They met in church while attending school there.

I know you are a lens designer. What was your major in college?

My daughter is studying electrical and computer engineering.

Awesome! That's the department I went through. Let's see.. My research advisor was Dr. Wu. Other profs I remember are Drewniak, Stanick, Borquin... well that's all that I can remember. I dormed in the Quad (I think it's torn down), then lived in a house near Kroeger. In grad school I had an apt in a building just off campus...conveniently close to the Grotto (is that still in business?) The apartment building was torn down and turned into a fraternity's parking lot several years ago.

I acquired a BSEE and MSEE. My last undergrad elective was a classic optics course, and it captured my fascination. I ended up sticking around for grad school to take optics and photonics courses...most of those were taught in the EE dept at the time, so I stayed there. I focused on electromagnetics and photonics, with a minor in history. They didn't really teach lens design. The Navy hired me right out of college (I chose China Lake over Boeing St. Louis), and I essentially taught myself lens design On-The-Job, as well as assembly, lens fabrication, etc. At some point the Navy gave me funding to take grad courses through University of Arizona to "backfill" the fundamentals.

My thesis is still filed away at UMR's (MIST?) library. Your daughter could probably look it up: http://scholarsmine.mst.edu/masters_theses/1970/ Something about cellular automata and its application for optical computing.

I try every so often to get a copy, but they refuse to release one beyond the bounds of the campus... not even a PDF. Kind of weird. My hard copy was destroyed in a moving van fire when we moved from CA to NH back in '10.

Best of luck to her. Rolla's EE dept has -- or had -- a *very* good reputation in the professional world. If she's going EE, suggest she not skimp on analog design (they will push her towards digital). It's all important.

-Jason

Alan Gales · Nov 30, 2016

Nodda Duma said:
Awesome! That's the department I went through. Let's see.. My research advisor was Dr. Wu. Other profs I remember are Drewniak, Stanick, Borquin... well that's all that I can remember. I dormed in the Quad (I think it's torn down), then lived in a house near Kroeger. In grad school I had an apt in a building just off campus...conveniently close to the Grotto (is that still in business?) The apartment building was torn down and turned into a fraternity's parking lot several years ago.

I acquired a BSEE and MSEE. My last undergrad elective was a classic optics course, and it captured my fascination. I ended up sticking around for grad school to take optics and photonics courses...most of those were taught in the EE dept at the time, so I stayed there. I focused on electromagnetics and photonics, with a minor in history. They didn't really teach lens design. The Navy hired me right out of college (I chose China Lake over Boeing St. Louis), and I essentially taught myself lens design On-The-Job, as well as assembly, lens fabrication, etc. At some point the Navy gave me funding to take grad courses through University of Arizona to "backfill" the fundamentals.

My thesis is still filed away at UMR's (MIST?) library. Your daughter could probably look it up: http://scholarsmine.mst.edu/masters_theses/1970/ Something about cellular automata and its application for optical computing.

I try every so often to get a copy, but they refuse to release one beyond the bounds of the campus... not even a PDF. Kind of weird. My hard copy was destroyed in a moving van fire when we moved from CA to NH back in '10.

Best of luck to her. Rolla's EE dept has -- or had -- a *very* good reputation in the professional world. If she's going EE, suggest she not skimp on analog design (they will push her towards digital). It's all important.

-Jason

Thanks for replying, Jason!

My daughter is in an apartment just off campus. It takes her 5 minutes to walk to her classes. She lucked out and got an apartment that was just remodeled and with new appliances before the last tenant. Some of those apartments are pretty rough.

Right now she is pursuing a double major in electrical and computer engineering. This will also give her a minor in math. She has all ready gotten most of her math courses out of the way at community college. This is her first semester at Rolla and she has just started taking actual engineering courses. She really enjoys it and is doing very well. I'm not sure if she will stay electrical or gravitate more to computer engineering. I told her that school is the right place to find out what she wants to do.

I'll tell her to look up your thesis and also about the EE analog design. Thank you for this information. I'll have to ask her about the Grotto.

The electrical engineering department still has a very good reputation in the professional world. She attended a job fair and talked to a representative from ABB. He gave her his card and told her that ABB would be very interested in talking to her after she graduates.

Alan

What are the grades of Optical Glass?

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