Computar Symmetrigon ..yikes!

Discussion in 'Large Format' started by jtk, Aug 24, 2007.

  1. jtk

    jtk

    Just won a Computar Symmetrigon 210/6.3 on 'bay. Very poorly described, so I just rolled the dice, paid little more than two Graflex lens boards...and it came with one. Literally mint, like new, immaculate...the Copal sounds perfect. But...holy cow! This thing's huuuuuge! The alleged 72deg coverage will nicely handle the fabulous Sinar-like movements on my Crown Graphic :) :) :) If the 4" built-in lens shade was removable (seems not easily) it could be a helmet for a certain crainially-challenged national leader. So... anybody use one ? How ? What do you think ? Sharp? Contrasty? That hood suggests anticipated flare... John
     
  2. They were among the best lenses that could be made with the techknology got the 1980`s. Contact Prof Lynn Jones at U. Texas Austin for more details
     
  3. If you think that is huge, wait till you see the Rodenstock Grandagon N 200mm f/6.8. That is one frightening hunk of glass - you'd be scared to drop it, for fear of losing your toes for good. Enjoy your lens!
     
  4. John - Sell it to me!
     
  5. Ron, I don't think Lynn Jones is at UT-Austin. He teaches (or taught?) at a community college in the Austin area.
     
  6. jtk

    jtk

    Ronald, I Googled hard before bidding...Jones' name did pop up, suggesting he was the designer. Found a couple of raves but didn't find much that was useful...the earlier Computar not-symmetrigon version was said by one person to have had even wider coverage, serious movements on 8X10. A Japanese, maybe a distant Kowa-related, Horseman-related fantasy. Given the coverage I'd imagine mere 4X5 will take good advantage of its sweet spot.
     
  7. john i have the 150 computar symmetrigon and it covers 8x10 ... nice lens you have there ... john
     
  8. jtk

    jtk

    j nanian...without heavy vignetting at infinity?
     
  9. nope, no vignetting ... mine has a "sunshade" on the front barrel, looks quite different than 15os i have seen posted here and there, and on eBoo.
     
  10. Damn! I was looking for one of those at a good price, and you got it!!
    [​IMG]
    I had one back in 2000 that I should have never sold.
     
  11. John, the page has long since evaporated, but at one time H. Lynn Jones had a rather more informative c.v. on the Austin Community College site. His present c.v. is at http://www.austincc.edu/photo/bios/lynn_jones.htm The austincc.edu also has an annotated list of lenses that he assembled. See http://www.austincc.edu/photo/pdf/usdlens.pdf I'm not sure everything there is correct, for example I'm not sure that Tokyo Optical marketed Kowa lenses. Of great interest, in it he says that f/6.3 Computar Symmetrigons are 4/4 double Gauss types (the Metrogon he compares them to is a double Gauss) that cover 70 degrees. This isn't at all consistent with other claims for their coverage. About his career and accomplishments, which are wonderful, in the old version he explained that while at Burleigh Brooks he induced Manuel Kiner, then at Ilex, to design some modern lenses. Among them were the Ilex Acuton, a 6/4 Plasmat, and the Ilex Acugon, very much like the f/8 Schneider Angulon. In their day, these lenses were fully competitive with their German counterparts.
     
  12. jtk

    jtk

    Sheldon, that's the one. Did you bid? I only bid at 27 seconds, had planned on a minute or two. To do the size justice the photographer might have shown it next to a lawn elf :) It was bizarre for somebody to have mounted it on a Graflex board, but that was exactly what I needed... Dan... You're an ace. Thanks for the links. Nice to know the background to arcane lenses. Do you know Lynn Jones? Did you go to Brooks? The only coverage claim I've found are 70-72deg, and someone questioning its ability to cover 8X10 with movements, Vs an earlier Computar that supposedly did. Do you think the Symmetrigon does offer 72deg or is Jones thinking of a different lens? John
     
  13. John, I don't know Lynn Jones. He and I have crossed swords occasionally here. He's made some assertions that I saw as outlandish and I've challenged him. All nice and gentlemanly. And I didn't go to Brooks. I'm poorly trained as a photographer. Used to get pointers from my little brother, who has a BFA in Photography from Ohio University and is a much better photographer than I am. And I've stolen many ideas from A. A. Blaker's books. The rest of what I've learned has come from somewhat directed trial and error. I suspect that the Symmetrigon doesn't have enormous coverage. It reminds me of the f/10 Process Nikkors. See http://homepage2.nifty.com/akiyanroom/redbook-e/ and remember that the circle at infinity is half the circle at 1:1 that Akiyan quotes. You might want to go over to http://www.largeformatphotography.info/lfforum/ and search for mentions of Symmetrigons. Search on www.apug.org too, for good measure. I may be mistaken, but I believe that someone, possibly Kerry Thalmann, has explained Computar LF lenses, including the Symmetrigon, fairly clearly on one of those boards.
     
  14. I have an original brochure for the Computar Symmetrigon lens. As relayed by Dan from Lynn Jones, these lenses are four elements in four groups. Bizarrely considering the name, the cross-section diagram shows them to be distinctly non-symmetrical. The design cross section seems roughly to be that of the Metrogon. (Sometimes we amateurs at lens designs may rely too much on cross section figures, e.g., we don't know what glasses are used.) The coverage is listed as 72 degrees. This isn't the same lens as the Computar, which is become a "cult classic" for extreme coverage. The Computar is 6 elements / 4 groups, and appears to be a plasmat type.
     
  15. Um, Michael, plasmat type Symmars aren't all that symmetrical either.
     
  16. jtk

    jtk

    Michael...could I trouble you for a copy of that brochure ?..nice to have with the lens for me or some subsequent owner... Dan, thanks...my photo background seems similar to yours...the best learning involves repeated failures coupled with lucky mentoring... Browsing has not produced real coverage data (which would have to be a user's experience on ground glass, not published info). I did see the observation about symmetry and about Computar Vs Computar Symmetrigon, but it was not supported by anything beyond assertion. Maybe I can find that again and email the guy, though I think the post was from the coal-fired Internet era. Wish I had my old Agfa Ansco 8X10... I don't happen to have (or currently want) any matte acetate for observational/metering faking-it purposes.
     
  17. when i get a chance i will mount my lens on an 11x14 camera and digi-snap the circle on the ground glass to make sure what i remembered from a few years ago was true. i have never *used* mine on an 8x10 .. but know i have had it on one to see if what the guy i bought said was a reality (i purchases the lens in 92' i stuck it on an 8x10 --- a couple of years ago)
     
  18. jtk

    jtk

    There's a 210 5.6 Topcor on that terrible site right now...Igor...looks about as big as my CS ... seller says the Topcor's multicoated. I may have seen a post somewhere saying they are related...?
     
  19. jtk

    jtk

    Without printing I would expect metering off ground glass would tell the story...wouldn't it? Would 1 stop falloff indicate limit of coverage?
     
  20. John, coverage is determined by sharpness, not illumination. Some wide angle lenses can lose several (up to 4) stops of illumination towards the edge and still have good sharpness there. That's why some people use ND center filters with them. If you go to Schneider's site and look at their MTF curves, especially the ones for Xenars, you'll see that at the limit of coverage, as Schneider defines it, contrast is near zero. I think that the Xenar circles of coverage, as Schneider rates 'em, are a little exaggerated. Same goes for G-Clarons, even though many many users assert that with them Schneider's circles are very conservative. Many people, especially shady or ignorant sellers on eBay, define the circle covered as the circle illuminated. This is usually much larger than the circle with usable image, especially with older lenses. Some, not all, modern lenses have field stops that vignette the cone of rays projected by the lens to limit the circle illuminated to the circle with usable coverage. An example is the Rodenstock Apo Rodagon D. If you go to, I think, Paul Butzi's site (time for self-help, use google to find it) you'll see at least the 75/4 1:1's MTF curves. They are high and flat. To me, this means the lens is really a wide angle lens with field angle restricted by a field stop. I used to have one; that's what it looked like in the flesh, sorry, plastic and glass.
     
  21. " Sinar-like movements on my Crown Graphic " What Sinar like movements and which Sinar? Norma, F, C, P, Alpina or the original wood portrait version, etc. The Crown is a press camera with limited front movements and no rear movements. That is hardly "Sinar like" unless you mean that they both had base tilts.
     
  22. Uh, Bob, relax. I think he was joking.
     
  23. jtk

    jtk

    :) Dan, thanks for the education.
     
  24. Hi John, The BBOI, Computar Symmetrigon lenses were available in 150mm, 180mm, and 210mm. They were all 4 element all air spaced, multicoated, based on the B&L Metrogon and the Zeiss Topogon. The lenses covered 72 degrees, and were optimized for 1:2 to infinity. The lenses were first class and were delivered with an appropriately designed lens shade. The were designed by Jan TerLuow, Dr. John Lawson, with the aid of me, Lynn Jones. The late J.D."Jack" Callahan, Pres. of Burleigh Brooks Optics authorized the design and manufacture for our wholly owned subsidiary, Computar, Inc. The lenses were manufactured by Kowa Optics at the highest quality level. I still have a 210 Computar ser#006, the first to be assembled and set in shutter. This goes back to about late 1977 if I remember correctly. I still show 3 prints from the first test photos. Best regards, Lynn
     

Share This Page