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Real difference between a Radionar and a Tessar?

Donald Qualls , Jul 29, 2003; 10:08 p.m.

I've just gotten a KW Patent Etui 9x12 (finally arrived, and it's in wonderful condition!). The one I have has the Schneider-Kreuznach Radionar 135 mm f/4.5, which (after a careful cleaning of the uncoated glass) seems extremely sharp to this long time, if casual, 35 mm and former 6x6 user -- but I've been told it's overshadowed by the Zeiss-Jena Tessar of the same length and ratio.

Now, the lens I have, on the nice clean ground glass in my camera, will let me pick out individual chimney bricks and tree leaves at close to 100 feet when carefully focused -- and this with the lens wide open to give the brightest image. I know the image on the film would be better than my eye can distinguish in either case -- but how much difference would there really be between these two lenses? How would I tell, short of enlarging to far beyond 8x10 or using a microscope?

Responses


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Robert Davis , Jul 29, 2003; 11:06 p.m.

Schneiders Tessar are the Xenars. I did a little looking around since I hadn't heard the name Radionar and it's supposedly a Cooke triplet.

Donald Qualls , Jul 29, 2003; 11:14 p.m.

Well, I'll take your word that it's a triplet; if so, it's got two elements cemented; I had the front and back elements off the shutter today to clean the surfaces (had something that looked like smeared skin oil on the front surface of the back element, and a general dirt/oil haze all over); there are only two groups, and though a good cement job is invisible, the front group, at least, appears too thin to be a cemented doublet. The back group is thick enough; front is a meniscus, while the back has a plano (or very long radius) front and a short radius concave rear.

If I ever do decide to replace the lens, I'll have to keep the Xenar in mind; in my little bit of looking, they seem less expensive than the Tessars.

Tim Hicks , Jul 30, 2003; 03:22 a.m.

The Radionar was a 3 glass design, made by schneider in several forms mainly for amateur use. There were versions with apertures from 2.9, 3.5, 3.8, 4.5 and 6.3. The longer F6.3 versions would have been respectable large format lenses for studio use at the time. 3 glass designs can be good if not stretched too far. At the other end of the scale the f2.9 version would generally be pretty disappointing at wider aperture settings as the design had been stretched a little to far but f2.8 Tessars can be disappointing too.

I would expect the f4.5 version to be quite acceptable when stopped down but not as good as a Tessar or Xenar. Uncoated pre-ww2 Tessars and even pre WW1 Tessars can be excellent. With all these uncoated lenses it pays to use a lens hood

The Radionar was a common mid-price option in the 1930's on Etui's and other cameras. In the 1940's and 50's it was commonly seen on rollfilm folders such as the Balda in the f2.9 and f3.5 form. These Baldas can produce a respectable result if used stopped down but they are not in the same class as a Super Ikonta as they were built to a lower price point.

Try the Etui out and enjoy it. If the results are good then why not seek out a Tessar version too, they are not rare and mine was not expensive.

Patric Dahlén , Jul 30, 2003; 04:10 a.m.

Here's some information about the Radionar from 1938. It's from Schneiders 25 years jubilee book.


Radionar

Patric Dahlén , Jul 30, 2003; 04:11 a.m.

Page two on Radionar.


More Radionar.

Patric Dahlén , Jul 30, 2003; 04:36 a.m.

Donald, as you can see, the Radionar is a lens with three elements in three groups. There are no cemented lenses in this construction. Look at this rather bad illustration I just made, and you see how the lens mounts are constructed. If you need the clean the back of the first element and the front of the second element, just screw the lens mount apart.


Attachment: Illustration.jpg

Patric Dahlén , Jul 30, 2003; 04:54 a.m.

BTW, I have no experience of the Radionar myself, but I have a couple of cameras with other three element designs. The Steinheil Cassar 2,9/50 on a 35mm camera is not especially good. It's too fast for a triplet.

On some Rolleicords I have the Zeiss Triotar 4,5/75 and 3,5/75. They are really good when stopped down to 8-11. Sharp and contrasty, but soft at larger openings. The sharpness at the edges is better with the Tessar.

Try your Radionar! You might like it, especially on a large format camera.

If you look for a Patent Etui with a Tessar, remember that the quality of the lens varies from example to example. You could spend lots of money on a Tessar camera that's inferior in sharpness to your Radionar.

Dave S , Jul 30, 2003; 01:52 p.m.

I guess since nobody else has pointed it out, I'll add that Rodenstock's Geronar is also a triplet design. They were (are?) also sold by Calumet as Caltar, and I think this was just a rebadged version. A triplet is not a bad lens, particularly at small apertures, but for LF work, you need to know it has a smaller image circle than symmetrical designs like Sironars and Symmars.

You guys talked about this recently here: click this link.

Dave

Tim O'Brien , Jul 30, 2003; 03:42 p.m.

Donald,

I had no intention of making you feel bad about your new lens. I do have a nice Tessar, I also have a Xenar and a couple of Ektars and a Fujinon W. All nice lenses. But... My collection also includes a Radionar, some Optars, some Novars, and a handful of other stuff.

If you look at my negatives, you won't be able to tell which image went through three groups and which four, unless I tell you.

Some of my favorite shooting has been done with my Zeiss Netters, with non-optimal lens on them. Zone focusing to boot. It's how you feel about the camera, your understanding of how that lens is going to work, and what you want to do as a photographer that determines the success of your work, not how many lines a lens will resolve at infinity halfway between center and edge.

That lens of yours will knock the socks off any 35mm lens you have been using. I love my Nikon 105 shooting 35mm, but sharpness? Any of the triplets I have will blow it away.

You might be able to tell on 16x20's but honestly, how many of us casual users go that big on a regular basis?

Have fun with your camera, as I have fun with mine (all of them).

tim in san jose


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