When did coating of large format lenses begin?

[tjvitale]

You know that large format lenses were uncoated until the 1980s. Schneider's for sure. That means unnecessary scatter from each air-to-air interfaces, the blacks will suffer.

Assuming a medium format camera, I'd be looking at medium or small form post-war German/Swiss lenses.

Super Angulon says Schneider to me, and that would set the format as large. If my guess is wrong and this is a post-war medium format lens. Cool.

Tim

[IanG]

You know that large format lenses were uncoated until the 1980s. Schneider's for sure. That means unnecessary scatter from each air-to-air interfaces, the blacks will suffer.

Assuming a medium format camera, I'd be looking at medium or small form post-war German/Swiss lenses.

Super Angulon says Schneider to me, and that would set the format as large. If my guess is wrong and this is a post-war medium format lens. Cool.

Tim

Schneider (and their competitors) started coating their lenses just after WWII, all my 50's-70's Schneider lenses are coated, in the mid 70's Schneider started Multi coating their lenses. Schneider's coating was very good and I've never had a flare issue with my 60's & 70's Super Angulon, and that's in conditions where the Zoom on my DSLR is unusable due to flare.

I'd add that initially Schneider added a Red inverted Triangle symbol to indicate a lens was coated but by 1960 had stopped as all their lenses were coated.

Ian

[tjvitale]

Please give some references for that.

I got my statement for many online searches. Books and The Schneider data sheet and website. I may have gotten some competitor disinformation on Wikipedia.

Happy to get the facts right.

Thanks

Tim
tjvitale <at> ix <.> netcom <.> com --- for email address remove spaces and carets
510-594-8277

[IanG]

Please give some references for that.

I got my statement for many online searches. Books and The Schneider data sheet and website. I may have gotten some competitor disinformation on Wikipedia.

Happy to get the facts right.

Thanks

Tim
tjvitale <at> ix <.> netcom <.> com --- for email address remove spaces and carets
510-594-8277


Your assuming that because post WWII brochures etc make no mention of coating that the lenses are un-coated. That's very wrong, the earliest post WWII Schneider advert I have isn in a BJP almanac f=1953 (published Autumn 1952) and the illustrations show the Red inverted Triangle indicating coating, That's about when the UK lifted draconian Import restrictions an. Coating was the norm on almost all lenses by the 1950s only cheap low end cameras had un-coated lenses.

Do a Google search like this one (https://www.google.co.uk/search?q=angulon+90mm+f6.8&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjjruXU6MLKAhUGWRQKHebXCPcQ_AUICCgC&biw=1366&bih=626#imgrc=p_1taMFe3VrXkM%3A) and you'll see that the lower SN post WWII 90mm Angulons have the Red (coated triangle) and suddenly it's dropped.

My 1956 Carl Zeis (West German) 150mm f4.5 Tessar is well coated but it's not marked as being coated unlike my post WWII (1953/4) CZJ version of the same lens has the T coating mark.

Ian

[Bob Salomon]

You know that large format lenses were uncoated until the 1980s. Schneider's for sure. That means unnecessary scatter from each air-to-air interfaces, the blacks will suffer.

Assuming a medium format camera, I'd be looking at medium or small form post-war German/Swiss lenses.

Super Angulon says Schneider to me, and that would set the format as large. If my guess is wrong and this is a post-war medium format lens. Cool.

Tim
Of course Schneider, as well as Rodenstock and Nikon and Fuji coated their lenses prior to the 1980s. You are apparently confused between uncoated, coated and Multi Coated. You should do your self a favor and research the differences.

[IanG]

Even post WWII Wray, Dallmeyer, TTH Cooke, Kodak lf lenses were coated here in the UK, same for US companies like Goerz AM Opt, Ilex, Wollensack, Eastman Kodak etc. Of the coated lenses I have only one or two have a symbol indicating coating. It really was the norm soon after WWII.

Ian

[Dan Fromm]

Please give some references for that.

I got my statement for many online searches. Books and The Schneider data sheet and website. I may have gotten some competitor disinformation on Wikipedia.

Happy to get the facts right.

Thanks

Tim
tjvitale <at> ix <.> netcom <.> com --- for email address remove spaces and carets
510-594-8277

Hmm. You are the one who's making outrageous statements. The burden of proof is on you. Please post links and bibliographic references.

[IanG]

Hmm. You are the one who's making outrageous statements. The burden of proof is on you. Please post links and bibliographic references.

I have a Schneider "Professional Lenses - Review" in front of me it's a small data brochure Schneider published, I think in 1970. It doesn't say coated anywhere but as we all know the lenses were by then and no longer carried the inverted Red triangle. I must scan this brochure and pass it on to Seth at CameraEccentric.

Ian

[BetterSense]

What exactly is the "single coating"? Is it magnesium fluoride? And what thickness? What exactly is multi-coating? I have never seen these terms defined.

[IanG]

Single coating was usually Magnesium Fluoride but quite early on Zeiss began using two layer coating, and things gradually improved and multiple coatings were used on many lenses.

The term Multi-coating, or more specifically Super Multi Coating, was a much more refined and balance coating system that almost completely eliminated reflections, it was first used by Pentax who had worked on the system with Carl Zeiss. A few lenses were technically already being multi coated before the term was used by Pentax.

Ian

[tjvitale]

I think I read the coating reference on the Schneider website, maybe in Wikipedia (but then I get a second source). Maybe I did confuse single sputtered coating and multi-coatings. The words are similar. I though it had to do with the size of the chamber used for coating. Certainly multi-coatings were occurring on small format lens even before the war in German lens-makers manufacturers. But it became restricted information, as war related secrets.

Being able to make superior reconnaissance photos was a big war secret.

And the size of the plasma chamber was the limiting fact well late 1950s and 1960s, I was told by a technologist.

This is what I've read.

BTW, if you can poke some other holes in my BHoIT, <http://www.vitaleartconservation.com/BHoIT.pdf>, I'm doing a re-write soon and very few folks have the knowledge to help.

Please try to limit it to items you have proof for, because I'll have to do the research.

ThX

Tim
tjvitale <at> ix <.> netcom <.> com --- for email address remove spaces and carets
510-594-8277

[Bob Salomon]

I think I read the coating reference on the Schneider website, maybe in Wikipedia (but then I get a second source). Maybe I did confuse single sputtered coating and multi-coatings. The words are similar. I though it had to do with the size of the chamber used for coating. Certainly multi-coatings were occurring on small format lens even before the war in German lens-makers manufacturers. But it became restricted information, as war related secrets.

Being able to make superior reconnaissance photos was a big war secret.

And the size of the plasma chamber was the limiting fact well late 1950s and 1960s, I was told by a technologist.

This is what I've read.

BTW, if you can poke some other holes in my BHoIT, <http://www.vitaleartconservation.com/BHoIT.pdf>, I'm doing a re-write soon and very few folks have the knowledge to help.

Please try to limit it to items you have proof for, because I'll have to do the research.

ThX

Tim
tjvitale <at> ix <.> netcom <.> com --- for email address remove spaces and carets
510-594-8277

Pentax introduced multi coating well after the war.

[Oren Grad]

Discussion about coating moved to its own thread.

[Taija71A]

You know that large format lenses were uncoated until the 1980s. Schneider's for sure...

I think I read the coating reference on the Schneider website...

1). No.
2). I don't think so...

As per the Schneider K R E U Z N A C H OPTICS Web Site:
https://www.schneideroptics.com/info/faq/photography.htm#q8

8. When did Schneider begin Multi-coating lenses?

The first Symmar-S lens to be multi-coated was the Symmar-S 150mm, serial number 13,014,862 in March 1977. The 210mm followed and then the rest of the focal lengths were completed by early 1978. The Super-Angulons were multi-coated in the summer of 1978 beginning with the f/5.6 series. The f/8 lenses were multi-coated in late '78- early '79. Apo-Componon HM lenses have been multi-coated since their introduction in 1986.

[goamules]

I think I read the coating reference on the Schneider website, maybe in Wikipedia (but then I get a second source). Maybe I did confuse single sputtered coating and multi-coatings. The words are similar. I though it had to do with the size of the chamber used for coating. Certainly multi-coatings were occurring on small format lens even before the war in German lens-makers manufacturers. But it became restricted information, as war related secrets.

Being able to make superior reconnaissance photos was a big war secret.

And the size of the plasma chamber was the limiting fact well late 1950s and 1960s, I was told by a technologist.

This is what I've read.

BTW, if you can poke some other holes in my BHoIT, <http://www.vitaleartconservation.com/BHoIT.pdf>, I'm doing a re-write soon and very few folks have the knowledge to help.

Please try to limit it to items you have proof for, because I'll have to do the research.

ThX

Tim
tjvitale <at> ix <.> netcom <.> com --- for email address remove spaces and carets
510-594-8277

Tim, I did a quick read of your Brief History of Imaging Technology paper. It has errors in facts, timelines, technologies, I would not submit it anywhere at this point. I suggest you get a few books, like the one by Kingslake, and read what true experts in optical history wrote. Wikipedia, websites, and "technologist" stories are no basis for a history paper.

Back to coatings. In WWII Wollensak coated their binoculars. I'm sure B&L did too, I'm holding a WWII pair that is coated. By the first year after the war, 1946, they were advertising Wocote (coatings) on their Raptar and other large format lenses.

Aug 1946 Popular Photography
https://c2.staticflickr.com/2/1600/23963495224_895c4b4663_b.jpg

[Dan Fromm]

I think I read the coating reference on the Schneider website, maybe in Wikipedia (but then I get a second source). Maybe I did confuse single sputtered coating and multi-coatings. The words are similar. I though it had to do with the size of the chamber used for coating. Certainly multi-coatings were occurring on small format lens even before the war in German lens-makers manufacturers. But it became restricted information, as war related secrets.

Being able to make superior reconnaissance photos was a big war secret.

And the size of the plasma chamber was the limiting fact well late 1950s and 1960s, I was told by a technologist.

This is what I've read.

BTW, if you can poke some other holes in my BHoIT, <http://www.vitaleartconservation.com/BHoIT.pdf>, I'm doing a re-write soon and very few folks have the knowledge to help.

Please try to limit it to items you have proof for, because I'll have to do the research.

ThX

Tim
tjvitale <at> ix <.> netcom <.> com --- for email address remove spaces and carets
510-594-8277


This is not a satisfactory answer. In addition, the bolded text in your response is incorrect if by "multi-coatings" you mean multi-layer coatings in the sense of Schneider's "Multi-Coating."

Here's an assignment for you. Chapter ten of the third edition of S. F. Ray's book Applied Photographic Optics is headed "Thin-layer coatings." One of the references is:

Berthel, F. (1973) The development of anti-reflection coatings for photographic lenses. Indust. Commer. Photographer 13, no. 5, 124. Find it and tell what Berthel said.

Here's another assignment for you:

Get a copy of A Lens Collector’s Vade Mecum. A book originally published on CD ROM, now available as a download from http://www.antiquecameras.net/ Find all of the references in it to coating. It says that TTH started coating in 1944, an assertion that I can somewhat confirm, having had a coated TTH Aviar lens made that year.

Go to www.cameraeccentric.com and look at the catalogs there. You'll find that EKCo and Wollensak started coating lenses for sale to the public in 1946.

I took a look at your www.vitaleartconservation.com/BHoIT.pdf Much in it is incorrect. Politeness prevents further comment.

[Paul Ewins]

The 1950 Schneider german language catalog devotes a full page to explaining their "Duroptan" coating and introducing the inverted red triangle symbol. I've got a contemporary (but different) english language catalog with the following entry:
Schneider "Duroptan" German Patent Nr. 685767
All newly manufactured Schneider lenses are coated. The "RED TRIANGLE" engraved on the lens mount marks the original anti-reflection coming "Duroptan" of Schneider lenses. It is a hard and durable "blooming" and the lenses may be cleaned without fear of damage.

The 1951 Goerz American Optical catalog also says:
Coating of Lenses
We furnish all of our lenses with reflecting surfaces coated. Uncoated lenses can be furnished on special order. Used Goerz lenses coated and adjusted if repairs require their disassembly.

If you follow this link you can see that Kodak's "Lumenized" coatings were being applied to the LF Ektars by 1945: http://www.bnphoto.org/bnphoto/KodakEktarsDB0a.htm

[Jac@stafford.net]

The 1950 Schneider german language catalog devotes a full page to explaining their "Duroptan" coating and introducing the inverted red triangle symbol.

I've seen some Schneiders with a white triangle ▽. Does it have a significant meaning?

[RSalles]

Zeiss in 1939, Kodak in 1940, and after all progressively everywhere,

Cheers,

Renato

[Bill_1856]

The effectiveness of coating was known since the early 20th century, (or maybe even earlier), but the mechanical process of coating was "invented" by Zeiss and Kodak in the mid-1930s. Some pre-war lenses were coated (or Luminized was what Kodak called it), but the process was mainly restricted to coat submarine optics during the war (classified secret), in fact some subs had facilities for coating on-board.

[IanG]

Zeiss in 1939, Kodak in 1940, and after all progressively everywhere,

Cheers,

Renato

No CZJ sold their first T coated lenses in 1936/7, I've seen more than one the oldest a 1150mm f4.5 Tessar. They may not have been available then on the open market



I've seen some Schneiders with a white triangle ▽. Does it have a significant meaning?

No, it is still coated.

Ian

[Randy]

While we are on the topic, I have a B&L 11X14 1C Tessar that has appears to be coated, at least on the front element. It has a very faint lavender hue. I purchased it a few years ago from a forum member and he mentioned in the listing that it looked to be coated. I have assumed that this lens was manufactured well before WWII. Am I wrong?

edit - or could it have been returned by the owner after purchase to be coated?

[Jac@stafford.net]

While we are on the topic, I have a B&L 11X14 1C Tessar that has appears to be coated, at least on the front element. It has a very faint lavender hue.

I have a few old, certainly non-coated lenses with what might appear to be coating, but I think it is natural coloration due to exposure to sunlight.

[Dan Fromm]

Ian, my late friend Charlie Barringer collected Zeiss equipment. One of his obsessions was nailing down when CZJ started coating lenses. I don't know whether he ever published -- he was one of the founders of Zeiss Historica and a contributor to the club bulletin -- but he could document coated lenses from the late '30s. Interestingly, not all lenses from that era were coated.

Randy, I'm not at all clear on when B&L stopped making Tessars but I have in front of me a 158/6.3 Tessar IIb with a pink and a yellow dot on the trim ring that appears to be coated a pale brown. I believe it is post-WW II, s/n starts with a "B" and its coating is light brown. What's your lens' s/n?

[IanG]

I have a few old, certainly non-coated lenses with what might appear to be coating, but I think it is natural coloration due to exposure to sunlight.

It seems to happen to certain glass types, it was noted quite early on. It doesn't happen to the new glass types used in the 30's which CZJ used for some redisigned lenses, and Leica used for the Summar, I've two pre 1930 CZJ Tessars and the fronyts look coated but the aren't, it's not sunlight just the right pollutants :D the wrong pollutants etched the surface of the newer 30's Schott glass.

On the other hand some lenses were retro coated after WWII.the first owner of my Agfa Anscom10x8 had the 12" Dagor coated.

Ian

[jp]

I have some US Navy binoculars from 1943 that are coated, and a rolleiflex from the late 40's that is coated. I'm sure there can be found a few lenses from the 30's but WWII brought us large scale coating.

Some pre-war lenses were refurbished a generation or so after the war and were coated perhaps by B&J or a subcontractor.

[IanG]

Ian, my late friend Charlie Barringer collected Zeiss equipment. One of his obsessions was nailing down when CZJ started coating lenses. I don't know whether he ever published -- he was one of the founders of Zeiss Historica and a contributor to the club bulletin -- but he could document coated lenses from the late '30s. Interestingly, not all lenses from that era were coated.

Yes I agree. I've seen uncoated 150mm f4.5 Tessar lenses dating to 1938/9 so only a very few were coated, the same goes for the coated 50mm Sonnars.

Now about 70 years on we (most of us) have no idea who those lenses went to, coating in Germany was supposedly a military secret, yet I've seen mention of it at CZJ in pre-WWII BJP Almanacs, TTH Cooke had done research work on coating and that may well have been kept secret.

So I think what's happening is CZJ coated lenses made when it was supposedly secret have now appeared openly on the market, who knows who originally owned them, but they exist.

Ian

[Nodda Duma]

What exactly is the "single coating"? Is it magnesium fluoride? And what thickness? What exactly is multi-coating? I have never seen these terms defined.

Single coating is Magnesium Fluoride (MgF2), and for visible is 1/4 wave thick, where the wavelength for vis is usually about 555nm (~138 mm). The reflection is reduced to ~1% per surface.

Multi-coating designs (materials) vary depending on specific requirements, but invariably each layer is 1/4 wave thick or a multiple thereof, and the outer layer is MgF2. Reflections are reduced to 0.25% or less per surface.

By the way...MgF2 is slightly soluble in water. So keep the condensation off coated surfaces.

[Bill_1856]

Immense numbers of older lenses were coated after the war by the used-lens powerhouse, Burke and James. They are usually recognizable by their pre-war shutters. (If you happen to see one of their catalogs from the late 1940s, you will go ga-ga at the huge choices and their minuscule prices!)

[tjvitale]

Thanks

Tim

[Ken Lee]

Why coat the outside elements ? Isn't the problem due to internal off-axis reflections ?

[Steve Goldstein]

Why coat the outside elements ? Isn't the problem due to internal off-axis reflections ?

Coating the outside of the front element would make sense to reduce reflections when using a filter. Filters are rarely used on the rear element, so coating there seems less important. It may be a manufacturing thing, perhaps it's simply easier to coat both sides of a glass than just one side. Nodda Duma would know.

[IanG]

Why coat the outside elements ? Isn't the problem due to internal off-axis reflections ?

I was thinking the same yesterday but more in terms of having a lens coated, the company who resurface my mirrors can coat lens elements, but it's not as hard and durable, I was thinking of just having the internal surfaces of a Dialyte coated, it all unscrews very easily. This was after some comparative test shots using a DSLR with a Dagor, a Tessar and a Dialyte.

Ian

[Dan Fromm]

Why coat the outside elements ? Isn't the problem due to internal off-axis reflections ?

To improve transmission.

[Drew Wiley]

To modern optical engineers, coating is more than just a tool to reduce secondary reflections and improve transmission. They can fine-tune various color properties of lens glass by the specific selection of coatings. This has become quite important as certain glass types have been withdrawn from the market due to allegedly toxic ingredients (in mfg, that is - I wouldn't worry about any lens in use). Coatings can be designed to resist dust and moisture condensation better than plain glass. There are all kinds of reasons. And there can be technical reasons to single coat rather than multi-coat elements. But aesthetically, we choose lenses for rendered look and not always for being hypothetically improved.

[Nodda Duma]

Why coat the outside elements ? Isn't the problem due to internal off-axis reflections ?

Transmission isn't necessarily a concern...an uncoated surface has ~4% loss which is significantly less variance than, say, the variation in mechanical shutter speeds from shutter to shutter.

More significantly, you could get a back reflection from the image plane (film or focal plane array) to that surface and back into the system which will cause veiling glare (lower contrast) issues and/or ghost images / ghost reflections).

Additionally, some glass types used as front elements can be softer or more susceptible to degradation by exposure to the environment than MgF2.

Finally, from a cost/marketing viewpoint, the question becomes "Why wouldn't you coat a front surface?". Knowing how coating runs go, the manufacturer wouldn't save an appreciable amount of $$ (there are still other surfaces to coat), and would run the risk of losing more in sales than what is saved when consumers who expect fully coated optics buy a competitor's lens instead.

[Bob Salomon]

Why coat the outside elements ? Isn't the problem due to internal off-axis reflections ?

One of the original benefits to coating lenses was to reduce scratching of the glass.

[Jac@stafford.net]

One of the original benefits to coating lenses was to reduce scratching of the glass.

However, reducing the possibility scratches was not the original objective. Earlier coatings were so fragile that cleaning a lens could wipe it right off.

[IanG]

However, reducing the possibility scratches was not the original objective. Earlier coatings were so fragile that cleaning a lens could wipe it right off.

That was exactly why I thought about just having the internal surfaces of a Dialyte coated, it was more hypothetical than serious. I had planned a few years ago to get the 135mm f4.5 Eurynar on my Orion Werks camera coated and then put it on a Patent Etui. however the company warned me their coatings were too soft to stand up to much cleaning. Then I found the lens & shutter were too large for my second 9x12 Patent Etui anyway.

since my rough tests on Saturday I'm more interested in the differences in lens contrast due to design and also coating and then Multi-coating, I scanned some transparencies last week that were shot woth a Rolleicord and a Triotar, I think Ektachrome E4 film and was impressed but I always found E4 more contrasty than E6 and the softness of the Triotar may well ahve helped.

Ian

[Two23]

Pretty easy to tell if a lens is coated or not, or multicoated vs. single coated. Simply allow a light to reflect on the front element. You can then check the serial number to see when the lens was made. I'm holding in one hand a Schneider SA 90mm f5.6. Serial number is 9962722. That dates it to ~1966. It's DEFINITELY coated. (single coated.)


Kent in SD

[DeKlari]

I've seen CZJ Tessar coated lens from January 1939 (before CZJ patent published in Dec 1939)
https://www.flickr.com/photos/126027782@N03/25892265375/in/dateposted-public/

[Jim Noel]

Somewhere I have an article on "invisible Glass" which discussed the light transmission of coated lenses. I don't remember the date, but it was written much earlier than any date mentioned so far. I will undergo a search for it and then report back.

[DeKlari]

Sure it was much earlier idea. I guess, most people wondering when it become available for public.

[noface0711]

I have some US Navy binoculars from 1943 that are coated, and a rolleiflex from the late 40's that is coated. I'm sure there can be found a few lenses from the 30's but WWII brought us large scale coating.