Mamiya TLR lens tests (broke my promise)

Discussion in 'Medium Format' started by tim_brown, Dec 5, 1997.

  1. One...more...time

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    Conditions:
    Film: Tech Pan
    Developer: Microphen diluted 1+5, 14 min @ 75 deg. F
    Illumination: Multi strobes, max duration 1/1000 sec.
    Magnification: 1:36
    Lenses: All black, 55, 80, 105D, 135, 180 Super, 250
    Body: C330, tripod, cable release
    Finder: Beattie Intenscreen w/ split prism, chimmney shade
    Target: Stepped target, stripes similar to USAF 1951
    Neg viewer: Zeiss microscope 100X

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    Edge limits legend:
    T=blurred tangential lines
    R=blurred radial lines
    C=field curvature

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    F-stop, center lp/mm, edge lp/mm

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    55mm:

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    4.5--57---25TC

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    5.6--71---32TC

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    8----71---40T

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    11---71---40T

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    16---63---45T

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    22---57---40T

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    80mm:

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    2.8--50---28TF

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    4----57---36TF

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    5.6--63---32

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    8----90---40

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    11---90---50

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    16---71---40

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    22---57---36

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    105mm:

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    3.5--57---36R

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    5.6--71---40R

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    8----90---57

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    11---80---63

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    16---63---50

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    22---57---50

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    135mm:

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    4.5--45---32R

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    5.6--50---40

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    8----57---32

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    11---63---28

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    16---57---28

    <p>

    22---50---28

    <p>

    180mm:

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    4.5--71---40T

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    5.6--80---50T

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    8----80---45T

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    11---71---45

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    16---57---45

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    22---50---40

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    250mm:

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    6.3--63---45T

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    8----63---45T

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    11---71---45T
     
  2. I'm sure that there has been a significant amount on Tim's part. Do these figures indicate that the lenses resolve well or not. Are we saying that 60-70 lp/mm is good, bad or indifferent? Pardon my ignorance......Ian
     
  3. The higher the numbers, the better resolution the lens captured at that particular f/stop. And of course the less blurring or curvature the better.
     
  4. In response to the newcomer's question about what the numbers indicate, I agree of course with the direct and simple answer. I almost always look to these resolution numbers to judge a lens. Some reviews give three numbers--the center of the negative (almost always sharpest), the mid-point circle, and the edges. In large format the outer edges must also be good because the lens is moved around in shooting.

    Anyway, my reason for this comment is: resolution is not the only issue. Some of the greatest (and most expensive) lenses are actually mediocre in resolution. After 20 or 30 years of practice, I have come to love many lenses--each for their own beauties. The practical shooter looks at a piece of equipment and asks: what is the best use of this? rather than the question: what equipment is best for everything?

    I first discovered this when I took a birthday portrait of a friend (I am amateur) in a wooded park and I deliberately shot into the light at large aperture with a Yashica twin lens, shading it to prevent obliteration of the image by flare, yet knowing the old modest lens would still show a lot of flare due to overexposure of the bright background. Never had I received such praise for the luminous result (and seldom since) because the modest lens was capable in proper use of many spectacular images--some quite sharp, some not so sharp but radiant nevertheless. Portraits are not often praised for high-resolution, and many other shots are the same.

    A lens that is not so high in resolution may have a beautiful, softer contrast so coveted by fashion and advertising photographers. In shooting outdoors with natural light (in the South) I greatly appreciate the reduction in contrast that some lenses have--and I may still need to reduce contrast even more for the effects I like (detailed shadows) by way of manipulating the exposure/development process.

    I think the 5-element Mamiya 80mm 2.8 twin lens may be a Heliar design (from Voightlander). One of the most prized designs ever produced, the Heliar has some residual uncorrected astigmatism, which of course reduces resolution. Yet it seems sharp. And it has beautiful skin texture and shadow detail both in studio distances and outdoors. One would have to learn to appreciate the performance in different situations to love such a lens properly.

    I think the 4-element Mamiya twin lens 105mm may be a Tessar design (from Zeiss)--perhaps the most popular all-purpose lens design of all time. Around f5.6 to f8 it snaps into a brilliant sharpness that is hard to beat in a wide range of contrasts, apertures and distances. It is designed not to require coating but of course even the earliest of these Mamiyas were coated.

    The Mamiya 65mm twin lens has 6 elements and may be a descendent of the fabulous Goerz Dagor--a wide angle design with two 3-element anastigmats back to back, the parent of the Schneider Angulons and later the Symmars (the first Symmars being symetrical Dagors, when they bought out Goerz).

    Anyway all these have excellent resolution and sharpness but they are each legendary due to the other features and qualities they offer. Like blondes, brunettes, and redheads--the statistics are not a direct measure of their beauty.
     
  5. Charles Osborne wrote: [...]I think the 5-element Mamiya 80mm 2.8 twin lens may be a Heliar design (from Voightlander). [...] I think the 4-element Mamiya twin lens 105mm may be a Tessar design (from Zeiss) [...] The Mamiya 65mm twin lens has 6 elements and may be a descendent of the fabulous Goerz Dagor[...] I happened to read this old thread and would like to add one or two comments. I fully agree with Charles when he says that resolution alone doesn't account for lens quality. The Heliar is a very good example. As for Mamiya TLRs, the only Heliar type lenses are the 105mm D and the 105mm DS (not the older plain 105mm design). The 80mm lens is not a Heliar. The 65mm lens is a great lens, but it is not a symetrical design and is certainly not a Dagor. Sebastien
     
  6. Another resurrection of a very old thread.
    I'm talking about the black lenses here only. Chrome may have the same or similar formulae, but the documentation I'm looking at is for the black lenses.
    The 65mm f/3.5 looks like an Angenieux retrofocus lens.
    The 105mm f/3.5 D looks likea Helliar design.
    The 135mm f/4.5 is a Tessar
    I haven't identified the "family" of any of the other lenses yet. I need to find a good text on the history of lens design.
     
  7. Try this link for Mamiya TLR lens optical formulas.
    http://medfmt.8k.com/mf/mamiyaclens.html
     
  8. Replying to this old thread because it pops up frequently on search results.
    The above link is down. But let me summarize the lens formulas!! Which you can also see, along with Tim's test results, here:
    http://www.xpan.se/DailyPhotoDiary/2011-07/custom/0013.html
    Anyways, down to the lens formulas:
    55mm -> it is a custom wideangle (retrofocus) lens, quite complex compared to the rest
    65mm -> The design is exactly as the old Angenieux retrofocus wideangle lenses, the first retrofocus lenses to be used commercially. It is also very similar to the early Nikkor 28/3.5 for SLR use.
    80mm f2.8 -> Identical to the Leitz "Elmarit" 90/2.8 of the fifties, 5 elements in 3 groups. Mamiya 127/3.8 lens for the RB uses exactly this design.
    80mm f3.7 -> Tessar design, according to Mamiya documentation (it's not a speculation)
    105mm f3.5 (chrome and black) -> Tessar, long focus design
    105mm f3.5 "D" and "DS" -> Heliar design, 5 elements in 3 groups.
    The case of the 105mm lens is very interesting. One gentleman on the old Robert Monaghan Medium Format forum told that, according to Mamiya engineers, the chrome lenses were "commercial formula lenses, engineered for maximum sharpness and contrast" and that "they were later recomputed to be less harsh at the request of wedding photographers". I believe they were referring specifically to the 105mm lens, since the Heliar design is world famous for smooth out-of-focus rendering, while the Tessar isn't it so. Also interesting is to note that a test of Mamiya TLR lenses (chrome lenses - 65,80,105,135,180) made in the mid-60s by Modern Photography rated the 105/3.5 (tessar) better than the 80/2.8 from f8 to f11, among the best results in the test, so we can't say that the 105/3.5 (tessar) wasn't sharp enough!

    The other lenses (65,80/2.8,135, 180 standard) did not change in optical formula when becoming "black", so it's not so obvious if they were "recomputed". They could have been recomputed still, but the basic lens design didn't change at all.
    BTW the best performing lens in that test was the 65/3.5, which doesn't surprise me.
    Link to the test (archived): http://web.archive.org/web/20060508231426/http://medfmt.8k.com/mf/mamiyatlrlens.html
    135mm -> Tessar design, long focus design. But in this case the diaphragm is on the rear of the lens. This is done to reduce the physical length of the lens itself. Alas, in theory this means performance will not improve too much when stopping down, and you can see this on the lens tests above by Tim.
    180mm, non "super" -> "Tele-tessar" design, telephoto lens. 4 elements in 3 groups.
    180mm Super -> Telephoto design not unlike some Canon/Nikon 135mm lenses for SLR.
    Please see this image for comparison between old and new 180mm, posted by myself elsewhere.
    http://static.photo.net/attachments/bboard/00b/00bWXd-530097584.jpg
    BTW the non-super 180mm is also a very sharp lens, at least about f8-11, with excellent bokeh. One of my best images was done with that lens. I also own the 180mm Super and it is as good as everyone else claims!
    250mm -> This is a telephoto design of 6 elements, not unlike other telephotos made by other manufacturers.
     

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