View Full Version : lens coatings and designs

John D Gerndt
30-Oct-2005, 20:09
The question is: how many of you have run your own tests on lenses shooting the same scene at the same time?

I just did this here in my 5th year of large format and really wish I had done it sooner. I shot 8x10 chromes so I coud really study the results not that one would need to; the result are obvious. I recommend this to anyone who really wants to know what is going on with their own work or the "look" of any other photographer's. It really is quite revealing.


Brian Ellis
31-Oct-2005, 04:03
Thanks for posting this but it kind of leaves me hanging in the air. What were you testing for? In what way are "the results obvious?" Were you testing one lens at different apertures, different lenses at the same apertures, or something else? The questions could go on and on but the point is that I think many of us would be interested in more information about exactly what you were doing, why you were doing it, and what the results were.

John D Gerndt
31-Oct-2005, 15:04
Sorry, got my own tiny world spinning...

I ran three lenses up agains each other, a 14 inch Emil Busch aplanat, a 12 inch coated Dagor from Amican Optical and a 14 inch Kodak Comercial Ektar (Lumanized 1953). The aplanat is uncoated 4 elements in two groups, the Dagor is single coated 6 elements in two groups and the Ektar is a Tessar - 4 elemetns in three groups, multicoated. I didn't have a 14 inch dagor so I had to go with a 12, that turned out to give some good information anyway... A 12 has a lot more depth of field that a 14. I can say a lot but you have to see the film to know what I mean. It was surprising to me how much.

One can predict the shift from uncoated to coated, you gain saturation and loose shadow detail, true. When you see how much it can be surprising. The aplanat is very sharp in the center, beat the Dagor and the Tessar but it gets steadily worse until the corners are displaying that cool smearing I have seen all these years on black and white images from the turn of the century before. It is interesting to see it in color! There was no color fringing with the aplanat. I expected a look like you get in carnival binoculars, the blue and orange chromatic abberations, but no. It just lookes smeared, coma. Ther is a lot of what I call blow-by where the light coming past the thin branches thins them out more and leaves a blurred trace along the edges of the branches. Shadow detail was outstanding but at the expense of a really flat chrome. Ho-hum.

With the coated Dagor you gian a flat field of uniform sharpness though DOF is not so impressive, kind of soft in the background (I shot all three lenses at f16 which should be about the peak for sharpness at a given focus and damn the DOF). The color saturation even with only 4 air-to-glass interfaces was lacking. It wasn't even a next-door neighbor to the Kodak, but the dagor still had really nice shadow detail (it was a contrasty scene).

The Kodak looked like a modern lens in every way, black tree trunks with no detail, brances looking like ink on paper and every color you ever saw in a paint box layed out just as you might hope, excellent saturation and detail on the area of focus. Not much DOF even at f 16 it had the worst of the bunch.

It is not that these results were unexpected, it is just that seeing the results with you own eyes is different than reading about it. I wrote the question to make people think about doing it for themselves. I wonder how many have. I highly recommend puting pictures to the words of wisdom that come from our good contributors.


Dan Fromm
31-Oct-2005, 16:17
I cheat. I use lenses for larger formats on 2x3. So instead of trying competitors out on their intended format or even on 2x3, I hang 'em in front of a Nikon and check central sharpness cheaply. In my situation, what they do in the corners of their intended formats is irrelevant. One source of variation in saturation is lens-to-lens variation in actual shutter speeds. So I use the Nikon's shutter.

Surprises? 150/9 Konica Hexanon GRII is no sharper, f/11 to f/22, than a 6"/9 Cooke Copying Lens and gives noticeably less saturated color. A lens hood might have helped the GRII. A 210/9 GRII is noticeably sharper at f/11, barely sharper at f/16, no sharper at f/22 than a 210/7.7 dagor type Boyer engraved << S >> and 1:1. The Boyer gives slightly more saturated color.

But and however, I've just finished, as in did the re-shoot this weekend, an exercise with all of the lenses I routinely shoot on 2x3. Same emulsion, same scene, scale varies with lens, and the same shutter for all of the front-mounted lenses. Had some problems, not all due to operator error, hence the re-shoot. But as far as I can tell so far, I don't have a clinker and even the lenses that don't cover the format -- 38/4.5 Biogon, 1.75"/2.8 Elcan -- do ok just about to their limits.

Two small surprises so far. If its vignetting was due to incorrect setup, the 305/9 Apo Nikkor at f/11 will beat the 12"/4 Taylor Hobson Telephoto at f/8 and f/11. I've reshot to find out. And at f/8 the 4"/2.0 Taylor Hobson beats the 101/4.5 Ektar at f/11. The Ektar won in a previous trial with both lenses shot at f/11.

Had a problem on the original shoot with the 4.75"/7.7 Aldis Uno, the oldest lens I carry around, but what I got was promising and consistent with other shots taken with it. Re-shot, we'll see. I mention the Uno because its the only pre-WWII lens I carry around. I have a couple of very old B&L IIb Tessars, but since I have better lenses at their focal lengths I don't use 'em much. Most of my lenses probably qualify as modern or not too ancient.

Oh, yeah, my lenses are un- or single-coated. The uncoated ones don't seem to suffer from it.


Ole Tjugen
1-Nov-2005, 06:43
Your findings are not really surprising (except for the differences in DoF, which I don't understand at all).

I did a similar test although on B&W film of 8 120mm to 150mm lenses: 120/6.8 Angulon, 135/4.5 Eurynar, 135/3.5 Zeiss Planar, 150/3.5 Xenar Typ D, 150/4.5 Heliar, 150/4.5 Apo-Lanthar, 150/4.5 Skopar, and 150/5.6 Symmar.

I sold the Symmar, and got the Eurynar replaced by a post-coated one. The Skopar, the Heliar and the Eurynar normally stay on their folding 9x12cm plate cameras, the Zeiss Planar and the Apo-Lanthar get used.

Lukas Werth
7-Nov-2005, 04:44
Interesting results. I have not shot any chromes with LF for a long time, and am not really into colour photography. One question turns up for me, however: is it really wishful in every case to get as much contrast as possible? Is shadow detail not aso to be desired? Just wondering.