I read recently that the best lens ever produced was the 1960 Zeiss Planar 50mm f2 as fitted to the Contarex. I thought this was a pretty bold statement to make but he was a lens designer although I don't know whether was a novice or an expert. However since I have such a lens in a Contarex ( not a nice camera to use) and also an f2 Planar in a Kyocera Contax, I did some tests. In B&W ( I did not do any colour tests) the earlier Planar was markedly sharper at 20x16. I would say also sharper than my Summicron in my Leica M. Is there anyone who is a lens/glass expert who can say what lies behind the so called expert's statement. Is there some technical reason such as a rare glass that is too expensive to use in mass produced lenses ? Personally the differences don't matter at all to me but it was a provocative statement which is supported by my amateur tests.

-- Anthony Brookes (gdz00@lineone.net), November 21, 2000

Answers

The planar lenses are legendary, but whether this is based in fact or urban myth is still open to question to my mind. The Contarex uses a leaf shutter I believe, and so will give less vibration than the FP shutter in either a Leica or a Yaschica. Like should always be compared with like.
I have a Zeiss Biotar lens, supposedly the same design as some planars, which is capable of astonishing resolution in the centre of the field, but quickly falls off toward the edges.
Personally, I don't think there was any magic ingredient in lenses of this era, apart from TLC in their construction.
It was an era which could combine the benefits of now vanished hand craftsmanship, with post war advances in precision machinery and computation. (Note the word 'could'). Planars in Hasselblads and Rolleis of this period are also highly prized, although they're quite different in design.

-- Pete Andrews (p.l.andrews@bham.ac.uk), November 21, 2000.

The Planar design is, as Pete says, legendary. The original design is credited to Paul Rudolph at Carl Zeiss about a hundred years ago. At that time, the only lens coatings were in Henry Taylor's lab, and so the Planar was more or less unmakeable: with that many glass-air surfaces it flared too much. So Dr Rudolph designed another lens, based on Taylor's Cooke Triplet, with four elements in only three groups -- the Tessar.

It must have been an exciting time in lens design!

With the advent of "bloomed" lenses in the late 1940s, the Planar became a reality. And the handmade build quality of Leitz, Zeiss and Rollei in the 1950s and 60s was quite remarkable. So your source's opinion is not a frivolous one.

Of course, there is a slight element of "Is Beethoven a better composer than Mozart?" in comparisons between the best lenses of that era.

And there is also a problem.

Single coating was available in 1960, but not multi-coating. And multi-coating revolutionizes contrast and colour rendition in lenses -- it is probably the second biggest technical advance in photography in the second half of this century. So I would be surprised if the 1960 Planar was not beaten -- even if only slightly -- by some modern computer-designed lenses using modern glasses and coatings.

Later,

Owl

-- John Owlett (owl@postmaster.co.uk), November 21, 2000.

Quite some years ago I did some comparison series with the Planar and f2.0 and f1,8 Nikkor standard lenses on slow B&W film shooting the proverbial brick wall for resolution. I then checked the negs with a loupe. Wide open and closed down one stop, the Nikon lenses won hands down... to get comparable sharpness with the Planar required stopping down to f4,0- f5,6. Now, this does evidently not cover other optical properties like bokeh and color rendition (which I remember as slightly warm). Still, it is a nice lens and the Contarex worked like a charm though 35 years old.

Karl Johan

-- Karl Johan Borgis (kjborgis@telia.com), November 22, 2000.

I don't want to derail this thread, but where the heck does this idea of 'bokeh' come from. It seems to have sprung out of nowhere, like so much other new-age drivel. Even the origin of the word isn't clear. I've heard it claimed that it's of Japanese origin, but it seems to me that it's simply a phonetic spelling of 'Bouquet'.
It's my contention that the out-of-focus character of the image is purely dictated by the shape, or number of blades, in the iris, and has absolutely nothing to do with the design, glass, or country of origin of the lens.

-- Pete Andrews (p.l.andrews@bham.ac.uk), November 23, 2000.

My old 1939 copy of 'Photography Its Principles & Practice' by C.B. Neblette covers objectives quite well. There's a bunch of text on the Planar and its history, but the last sentence is telling: "The relative aperture of the Planar is f/3.5, but owing to the presence of considerable coma the definition at this aperture is not critical and stopping down is necessary for critically sharp definition. The Planar is no longer made, having been replaced by the unsymmetrical anastigmats which have approximately equal speed and superior correction." Now, the later Planar may be different in the glasses used or the exact design, since it's faster, thus the only meaningful answer will probably come from testing it. Still fun to think about.

On bokeh, I'm still skeptical though most now think the degree of correction for sphereical abberation is involved. I did at one time collect a bunch of 50mm lenses of different vintage and design, all fitting a Nikon body. I shot the same scene with each, said scene having highlights on water and other things bokeh supposedly affects. I was careful to compare only shots taken at the same aperture and with the same focus point. My conclusion was that I couldn't see any difference at all in the out of focus areas, or much of anything else. I suspect the more variables you remove from the test, the more bokeh might be a preference for certain focal lengths or apertures. I've yet to see a properly conducted test that shows any significant difference between two lenses of the same focal length, shot at the same aperture, of the same scene, on the same type of film. I will of course instantly change my mind when confronted with any real data that says something different!

-- Conrad Hoffman (choffman@rpa.net), November 23, 2000.

Regarding Bokeh, here is a link that compares two 35mm f2 lenses. It does show the difference, even they are Pentax, though. http://www.takinami.com/yoshihiko/photo/fa35/FAvsK.html

-- Derming Duh (dmduh@yahoo.com), November 23, 2000.

If you look up the term bokeh on altavista, you will find a number of sites relevant to the topic. I seem to remember the articles in Phototechnique dealt with the term in principle. At the time of my lens comparisons, I only did tests for resolution only on photographic film.

Hope this helps.

Karl Johan

-- Karl Johan Borgis (kjborgis@telia.com), November 24, 2000.

OK. I've done a bit of research, and it appears that the word should actually be 'Bo-ke', pronounced as in 'spoken', so why we westerners put an 'H' on the end is anyone's guess.
This business about spherical aberration doesn't really hold water, especially when bad boke is attributed to 'over-corrected' spherical aberration. No lens worthy of the name has first order over-corrected spherical aberration. Any over correction would be in the Seidel 3rd order, or 5th order zonal corrections, which are of very low magnitude.
I find it hard to believe that these tiny errors can make a visible difference to an out of focus blob several millimetres across. Furthermore, since these are zonal errors, it should be easy to test the hypothesis by simply stopping the lens down and seeing if the character of the boke changed significantly.
A more likely explanation, to my mind, is whether the iris is positioned absolutely correctly at the optical centre of the lens. This position is well known to be critical to the geometrical rendering of the lens.

Anyhow, for the last 150 years, both photography and photographers have got on quite well without concerning themselves over 'boke'. I doubt that any of the world's great photographers will find themselves demoted because they used the wrong lens.
It also seems strange that the Japanese should concern themselves with this phenomenon, but not be able to control it in their lenses.

-- Pete Andrews (p.l.andrews@bahm.ac.uk), November 24, 2000.

Well Pete, I went and looked at the site Derming suggested. It looks like a reasonable comparison, and the difference is obvious. I still have to wonder if we're looking at some off axis contrast and resolution difference. I wonder if the effect would be the same on center. The thought also occurs to me that one could make a Bokeh test target, sort of like a USAF target only with various size white circles. You'd shoot it out of focus, then evaluate the edges of the circles. Take a look at the two photos and tell me what you think- I've been curious about this for quite a while.

-- Conrad Hoffman (choffman@rpa.net), November 24, 2000.

I did not realise how well repected the 1960s Planars were till I read the replies and some e-mails sent to me directly. There seem to be a great number of people who enjoy testing lenses against each other. The sum of all the emails is that many seem to think that the Planar of the Contarex was possibly the best lens ever made - no doubt there were some not quite as good as the others - and that it was made in an era before plastics and mass production. An interesting email from Australia was from someone who had tested the Contarex Planar against current Planars, old and current Nikon, Canon and Pentax lenses. etc. He says that none of them come near to the resolution and correction of the 1960s Planar so even Kyocera aren't keeping up the brand. Thanks for all your interesting comments. (By the way the Aussie now uses a Pentax 6x7.)

-- Anthony Brookes (gdz00@lineone.net), November 25, 2000.

Hi Conrad, and sorry to fragment and hijack your thread this way Anthony.
I've looked at the URL in question, and I agree that the images are very different, but I'm not 100% convinced. The little clip that's supposed to show the AF lens at f/2.8 actually looks more blurred than the supposed f/2 clip. There's also a subtle shift in viewpoint, and that doesn't help with a comparison.
As you say, Conrad, it needs a proper test target and more controlled conditions to really determine what the effect is. It may even come down to something crazy like air bubble inclusions in the glass, or the cleanliness of the lens.
I've recently aquired a very sophisticated computer optical simulation program, which can generate spot diagrams for through-focus conditions, and the change from 'doughnut' to gaussian light patches can easily be seen as a lens passes from positive to negative defocus. What parameters affect this, I've yet to determine.

-- Pete Andrews (p.l.andrews@bham.ac.uk), November 27, 2000.