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Thread: Lens test surprise

  1. #1

    Join Date
    Jun 2001
    Posts
    341

    Lens test surprise

    Hi all, Did some lens tests the other day ...man was I in for a surprise.I have never bought a brand new large format(only bought used) lens but am considering just that for future purchases based on the results of these tests.I shot a Goerz f9 RD 240mm, Schneider 135mm 3.5 Xenar, Schneider 180/315 conv, and a 127mm Graflex Optar 4.5.All lenses in great shape and late coated. All shot under the same co nditions and enlarging only the middle of the neg...shot using middle apertures or f22.The worst was the 180 conv.which was ok in the middle and soft in the cor ners.Next worst was 240mm Goerz.This lens is very good but not superb..will prob ably use on 8x10 for contacts mostly.The next best was the 3.5 xenar which had a very nice rendition...as well as a bright screen, a keeper. But the big surpris e was the 4.5 Optar that creamed the competition not only in resolution but cont rast and rendition as well.This lens was a LOT better than the others and with a few polish marks to boot...go figure.Anyway...I have always liked this lens and admired it's quality but heard that the other brands would be better a better i dea.Not so I think...at least in this case. Anyway, I give the 180mm a 7 score, the 240mm a 8, the 135mm xenar a 9, and the 127mm Optar a 9.8....Got to leave a little bit for a 10 score!I'm probably going to get a 110 xl next or a 180 siron ar s and they better be a 10!

  2. #2

    Join Date
    Mar 2002
    Location
    now in Tucson, AZ
    Posts
    2,980

    Lens test surprise

    surprise, surprise. "Graflex Optars" have a mysterious history. Earlier ones are supposed to be 4-element Tessar types, later ones 3-element triplets of mediocr e quality. I don't know if this is true, or how to tell them apart, assuming the re are two different types. Graflex of course did not make lenses. This lens may have been made by Bausch&Lomb, Kodak (think Ektar) or by Wollensak, all in Roc hester. Your lens was almost certainly original equipment on a Speed Graphic. En joy!

  3. #3

    Lens test surprise

    Emil: Glad you stroke gold! Not to dispute your results, testing lenses for LF cameras is a tricky thing because of the difficulty of keeping all variables under control. Holders can be a big variable. The only holder I know to come under truly strict tolerances, i.e. 0.001" is Linhof, which I tested along many others with a depth micrometer; Sinar holders also are guaranteed to similar tolerances. As for other brands of holders, it is a game of chance. Logically, positive results are true but negative results may or may not be true for the above reasons. Lens tests using calibrated holders on a camera with a calibrated groundglass is IMO the absolute minimum for lens testing. If you did not do that, do not throw the Goertz out, it may be worth re-testing. The Xenar should give a crisp image at the center of the field which degrades rapidly away from center especially considering its minimum focal length and small IC for even 4X5. For the price paid it may be cost-effective but today there are far better lenses as for example the Apo Symmar or Apo Sironar. Yet, to keep all in balance I must own to the fact that good lenses do not necessarily take good pictures, photographers do. Enjoy!

  4. #4

    Lens test surprise

    It has been mentioned here before, but try here for lens test results on many modern, and classics.

    http://www.hevanet.com/cperez/testing.html#100mm_thru_163mm

  5. #5

    Join Date
    Dec 2001
    Posts
    103

    Lens test surprise

    It just goes to show that sometimes a lens can be under-rated. I have some Raptars (same as Optars?) that are very very sharp and contrasty.

  6. #6

    Lens test surprise

    While you did not specify how you were doing the resolution tests, I must agree with Julio, and urge you to be very careful about the results of your testing. I have tested the same lens, a 210 G-Claron, five or six times, each time getting remarkably different results, ranging anywhere from less than 20 lines/mm to 80 lines/mm in center, that is, from a soft lens barely usable to an excellent sharp lens. Hmmmmmm. Alternatively, to throw a wrench into the works, each of the three times I have tested my 4 3/8" WA Dagor, I find it CONSTANTLY testing at 75 lines/mm in center. No explainations... What is clear however, as you have found, is that lens performance is often very surprising!

  7. #7

    Join Date
    Jun 2001
    Posts
    341

    Lens test surprise

    Yes I realise that I might have a different result on a different test. So I did it again ....with the same results.The holders are brand new and I was pretty picky(technique) but not obsessive.The only thing I think I need to do is run through the whole f stop scale on each lens.To my eye the Goerz looks sharper closer to wide open than closed down to f 22.I did not use a test chart...but used three dimentional objects with great detail so I could see how the lens put together tonalities as well.I made multiple prints in the darkroom so I could be sure the enlarger didnt shake too.Still, the 4.5 Optar kicked butt!

  8. #8

    Lens test surprise

    Emile: The age of the holders is irrelevant to the issue of the holder's accuracy of registration. Brand new holders of a very popular and cheap brand are notoriously inaccurate. Out of curiosity, which brand did you use?

  9. #9

    Lens test surprise

    Given the following: 1. only a few years LF experience 2. I am not a math / optics genius 3. I don't have a million dollar optics lab ----

    How can I reasonably and tolerably accurately calibrate my LF cameras, lenses, holders. That is check them out, calibrate them, test them so that I know I am getting the best out of my equipment. How can I tell if my holders are in / out of spec. Is there a reasonably easier to understand / follow checklist or how-to to go through the process. What tools do I need and can they be afforded on modest budget? There is a lot about how to do Zone in excruciating precision, but about the rest of the calibration necessary to get good, consistent results without black magic?

    TIA

  10. #10

    Lens test surprise

    Paul, may I suggest taking pictures and dont worry so much about all those test? If your pictures come out blurry and you are absolutely sure you focused them correctly then worry! if not, why fix something that is not broken? I been using my 4x5 for 10 years and dont have any idea what a resolution chart looks like...:-))

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