Uncoated Lenses: Just As Good?

A lot seems to be made of lens coatings -- be they single or multi -- but a

recent, very informal, test I conducted makes me wonder just how much there is

to this distinction, to the praise that's often showered upon lens-coating. All

right if longer-focus or zoom lenses -- items with many elements arranged with

great complexity -- benefit significantly from being single- or multi-coated,

but the little match I set up between my old, uncoated 2/58 Biotar (Exakta) and

somewhat more recent coated 2/58 Biotar revealed no discernible difference in

results. In fact, the only advantage the latter offered -- other than greater

ease-of-operation (it's semi-automatic, while the former is fully manual) -- is

rather closer minimum focusing-distance. So, in your experience, when it comes

to prime normal lenses, do coatings really matter very much at all? Thanks.

My results have been definitely yes...the reduction in flare has been quite distinct for me.

Having compared 50mm 3.5, 90 4.5, 135 4.5 coated and uncoated versions, I can say there

is a hugh contrast increase from coating and that details available in shadows and highlights

are significantly greater.

 

Multi coating produces some small contrast increase, but its main advantage is in controling

flair.

When it comes to flare, I'd suppose lens hoods are far more important than lens coatings, no? When you speak of contrast, is the difference more noticeable in B&W film or in color? My informal test was conducted using a roll of 35mm B&W film.

With tests like these there would be different results depending on subject, lighting, color or B&W, slides or prints, IOW many variables. I have shot with uncoated lenses but in circumstances and with finishing that minimized their disadvantages. However I wasn't comparing similar lenses, coated vs uncoated but was just dinking around with old lenses to see how they would preform. The most fun is an old Tiffen, series 5, +10 close up supplementary lens that I mounted in a gutted, 135mm T-mt lens focusing mount. Makes a nice 100mm soft focus portrait lens and can be stopped down to control the degree of softness.

I think lens design plays a much greater part than coating. I use a number of 1930s f/4.5-f/4.8 tessar-formula lenses in medium format, and they're in no way inferior to their coated brethren from the '50s and '60s. In 35mm, I've happily replaced a couple of single-coated 50/2 Jupiter-8s with a single-coated 50/3.5 Industar-22 of similar vintage; The latter is a (four-element) Tessar design, and is every bit as contrasty and flare-resistant as I could ever ask for; the former, a rather more complicated (six-element Sonnar) design, were of course faster, but had absolutely abysmal contrast and suffered horribly from flare under even the best of circumstances. Indeed, among Soviet rangefinder lenses, the Industar-61 is infamous for its extremely high contrast (and sharpness), and it is, perhaps surprisingly, a "mere" four-element, three-group tessar design. Sometimes, simpler *is* better. :)

I think there is a definitive difference.

I ran the uncoated Kodak Ektar 101mm 4.5 Tessar, and the 105mm 3.7 Heliar, side by side with thier exterior coated later versions.

Both lengths are considered fine lenses. Arguments have been made over which is the sharper preferable lens.

The test shots I made showed each lens to be superb. The big difference was a dramtic change in contrast for coated to uncoated versions. Plenty enough to warrant considerations in development. Some shots I made with mottled light showed the hot spots to be nearly washed out in the high lights with the dark shadow full black with out printable detail with the coated versions. The same exact shots with the uncoated lenses were a little the other side of a nice printable negative and rendered a much flatter or muddy image.

Though I registered this significant difference, I am not saying one is better than the other, but the difference suggests a very different result, though all images were nice and sharp. Depends on what one wants in the finished result.

The image below was shot with an early 1900's 7" Cooke 5x7 triplet, at f~4.7 1/1000th on a Speed Graphic using a 2x3 roll back and using about a 35mm format crop (distance about 7ft). IIRC the film is Kodak 100G. the lens is certainly uncoated, but I see no problems.

SG, at even odds you saw differences in exposure due to differences in shutter speeds, not differences due to the lenses themselves. The only way to be sure when doing a shootout is to use all of the lenses with the same shutter. Since you have a Speed, this means using the camera's focal plane shutter, not the shutters the lenses are in.

 

I make this suggestion because I have the same models of lenses and the results of my shootouts, done with the FPS, aren't consistent with yours.

According to Ansel Adams in one of his books, uncoated lenses will typically require an adjustment in exposure to compensate for light lost to flare. Sometimes this is on the order of +40%.

 

So, you'd have to run your film tests with any given lens to find the optimum film speed and developing times for a given lens/film combination.

 

Once you've done that, you'll probably find that the main differences would be increased shadow detail from the uncoated lens, along with perhaps a slightly different rendering of color.

Yes, coatings make a big improvement to the image quality. However when you think that almost all photos taken before 1945 will have been taken with uncoated prime lenses you can see that with a good eye and a careful technique strong images can be made with uncoated lenses. In my experience uncoated lenses have higher flare and lower contrast but most importantly are more restricted in the circmstances in which they can be successfully used. You have to be more aware of the probability of flare occurring and adjust your technique to avoid it.

With uncoated lenses a simple design such as a Tessar is often used so there are not so many air to glass interfaces. A more complex Planar is just as old about as the Tessar; but was not used much until coatings became practical. In the USA Kodak had coatings on the Kodak Bantum and Kodak Ektra before Pearl Harbor. During the war the military had the aero Ektar and the Ektars on speed graphics coated; plus many binos and other optical items. With a complex zoom lens a coating makes a huge difference compared to a triplet or a tessar; since there are many more lossy air to glass interfaces.

Michael Gilday: the Sonnar you mention is also a 3 group design. Since its the number of glass/air interfaces that matter, there is theoretically no difference between a Tessar and a Sonnar in terms of flare.

 

There are other factors just as the diameter of the glass and how recessed the front element. That and not to mention haze, oil and other afflictions that should be corrected before making any definitive comparisons.

 

I had a 7 element 3 group 50/1.5 Sonnar of prewar vintage for the Contax RF camera that was fantastic. I would say even sharper than the superb postwar 50/1.5 West German Zeiss Sonnar I had, though somewhat more susceptible to flare.

It is noticeable in monochrome as lower contrast, see the comment about Ansels book, and in color with lower contrast and less color saturation, ie a pastel coloration.

 

You do not get more shadow detail with and uncoated lens. The shadows are brighter and higher up the curve and lack contrast, but you do not go deeper into the dark tones and get more detail.

 

Lens shades help with flare, but there is also light and contrast losses between each lens element and no shade can fix that, only coating.

 

If the lens is fogged up internally, you can not see a differencce, but with clean lenses there is a world of difference. Shine a small pen light through and the elements should look clear.

Kelly, its funny. As soon as TTH introduced the OPIC, an f/2 6/4 double Gauss type, and its immediate descendant the Speed Panchro, really serious professionals ("Hollywood") began to use them, and in the most exacting applications. I can't imagine why the design type wasn't good enough for the amateurs who shot 35 mm with, e.g., Leicas and Contaxes. Schneider's Xenon, another f/2 6/4 double Gauss type, was used, and I think happily, by the amateurs who shot 35 mm with Retina IIs. I'm referring to uncoated lenses, mainly pre-1946, not to post-WWII coated ones.

Dann,

The comparisons I made were done using a Speed with an accurate focalplane shutter on a sturdy support. I only changed lenses. I have done this a few times. And I think the most accurate shutter is a good running FPS. Esspecially considering old leaf shutters like the Supermatic can be as much or more than a full stop off.

SG, thanks for the response. Still and all, we got different results with uncoated 101/4.5 Ektar and coated 105/3.7 Ektar. So I have to wonder about your 101. Are you sure it was clean?

 

Cheers,

 

Dan

If you shoot with a contrast filter on B&W film you shouldnt notice any major difference. You can also process your B&W film specifically to bring out stronger contrast. Should lack of coatings or lack of multicoatings prevent you from shooting with a certain lens or camera, or from buying a lens at a great deal? Heck no. Should it make you adjust how you shoot a little bit to compensate? Yes, but less than you should be compensating between shooting B&W films and color films IMO.

Dan I know I still have the older uncoated 105 3.7, but not sure about the 101.

Yes they were all clean and clear, perhaps not perfect, but very near so withthe camera position well in the shade purposely.

I don't have time to do it again tight nowbut will try soon. and see if different results and re-post something on the

difference.

Stephen

Stephen,

 

I sold my old 105/3.7 (coated) because I much preferred my 101/4.5 (uncoated). Since then I've heard so many happy noises about the 105 that I've bought another, in gummy shutter and attached to a 2x3 Crown. Its shutter is in the shop, should come back sometime or other. Soon, I hope. When it does I'll be able to redo that comparison too. It may turn out that my first 105 wasn't up to standard. I do know that my uncoated 101 is a hair nicer than my coated one.

 

Its been a while since I did the "which normal lens for 2x3 am I going to carry around?" exercise. Since then I've accumulated a bunch of 'em, not all coated, so I'm planning a redo. Probably next year after all of the lenses are in shutters (won't use 'em for the exercise but need the diaphragms to work) and on board. To get the answers I want, I'll have to find a subject that will let me evaluate image quality in the corners as well as centrally.

 

Cheers,

 

Dan

Hi All,

 

If you compared a new uncoated lens to a coated lens you would see a huge difference, especially with lots of air/glass serfaces like an Artar (8 air/glass) or Cooke Triplet (6 air/glass). This the reason that some of the cemented lenses such as Dagor glass and some of the 8 or 10 element convertible lenses had only 4 air/glass surfaces. You would lose upwards of 20% of the light with uncoated optics air/glass surfaces!

 

The reason you are seeing reasonably good performance from uncoated lenses is that they ARE coated. Self coating takes place over a period of 15 to 30 years, however be very careful not to rub the lenses with tissue or what ever, the self coating is very fragile. When I was young in the business (50 ormore years ago), you could get "killed" for touching a lens with other than compressed air or a camel hair brush get. In the 1920's H. Dennis Taylor (optician-astronomer) creator of the "Cooke Triplet" researched and wrote a paper on natural lens coating and the differences between that and new uncoated lenses.

 

The earliest "artificially" coated lenses of which I'm familiar were from Burke & James (Chicago, IL) in about 1928-1929 based on the research of a lady PhD candidate from USC or UCLA. Some of the lenses were coated and some were not, the differences were so great that B&J recalled all of the uncoated lenses and replaced them. The owner George Drucker, was a friend of Taylor and because of Taylor's advice took a chance of the coating as well as Taylor suggesting to George that he buy Goerz Optical which was for sale by Zeiss at that time. George Drucker was my friend from my late teens until his death at age 99 in the 1980's and interestingly I became Vice President of B&J a few years after George sold the company.

 

My experience with single coating and multiple coating (which can be from 2 to 7 coatings)only seems to make a great deal of difference with super wide angle and very multiple elemented lenses. 4, 5,and 6 element lenses don't seem to make much if any difference assuming that the design and manufacturing is good and the angle of view doeasn't seem to be over 70 degrees. Some of the greatest lenses I ever seen have been 4 element tessar type lenses as well as some of the 5 element Ektars and 6 element plasmat types from Ilex in the US and Rodenstock.

 

7 coatings were invented by a California telescope optics company (OCLI) I believe in Santa Clara and the US importer of Asahi Pentax was so impressed that they demanded that Pentax pay to license the system (even though the patent would have expired in 2 or 3 years). Nikon and Leitz both a double coating process in some of their internal elements, especially with some of the true telephotos which until the mid 1970's were a serious problem anyway.

 

Lynn

Dann,

I just remembered I have another mini-speed on the way and I think the 101 on it is the uncoated version,since it lacked the luminized marking, but I know some of the exterior coated ones don't necesarrily have the circle "l".

Maybe I'll try and set something up this weekend and shoot a test roll. I need to check out a couple Pentax lenses (50mm 1.7 and 135mm 3.5) anyway, so will be in developing mode.

Imay not post here, but on "Lense Help" at Graflex.org sinceit's beenslow overthere anyway... Who Knows?

Big difference

Lynn, you keep telling us that B&J started coating lenses in 1928-9. Fine, wonderful. Where are these lenses now? And where are advertisements touting this wonderful new feature?

 

If B&J had the technology first, why didn't they patent it? Why didn't lens manufacturers (AFAIK, B&J was primarily a jobber. Am I mistaken?) license the technology?

 

AFAIK, the first patents for coating belong to CZJ. And 50 years ago nearly all lenses were hard coated. So why the prohibition on cleaning?

 

Cheers,

 

Dan

Stephen, thanks for the news. A couple of years ago Les Newcomer and I ran in circles for a bit trying to figure out when EKCo started coating in earnest. Everyone says 1946, but the 101/4.5 I've been talking about has an 1946 serial number (E0 3946) and we've both seen other EO Ektars that have the circle-L mark and are obviously coated. So the s/n of the 101 on y'r inbound Mini Speed may not be informative. But the coating on all of the for sure coated (with circle-L) Ektars I've seen has been pretty obvious.

 

Cheers,

 

Dan

Lynn, soon after acquiring it, after spraying it with glass-cleaner, I gently Kleenexed my uncoated Biotar; I'm pretty sure whatever "natural coating" it had vanished right then -- :).