Wide Angle Lens For FF and Contax645/EOS Lens Adapter

Discussion in 'Digital Photography' started by Einst Stein, Oct 29, 2006.

  1. Einst Stein

    Einst Stein Guest

    After a repeated failed bid on MF digital back, finally I got my
    compromised 35mm DSLR.
    But then I realized why 35mm FF is not always a good idea, if wide
    angle lens is important.

    Every medium priced under 50mm has serious cornor light fall-off. Some
    have serious color shift too. This includes Canon non-L, Contax-Yashica
    35mm, and Rollei 35mm, including prime and some zooms. From what I read
    from dpreview's forum (canon/Kodak SLR), the canon L could be better,
    but not satisfactory.

    The only thing I found acceptible is Hasselblad's 50mm, but again, it
    is f4 only. I don't mind to carry the bulky and heavy stuff, because
    this is my down graded Med Format. The problem is, I really want a 35mm
    lens. Hasselblad only goes to 40mm. The 38mm won't work on 35mm DSLR.

    I can find Contax-645 35mm lens. The general comments are it's really
    really good. So I really wish there is an adapter for Contax 645-to
    EOS. Anyone knows if it exists? I know Contax N would be difficult (or
    even impossible) to adapter to EOS, but Contax 645 should be OK.

    Or, which 645 format 35mm lens is good too (Mamiya, Pentex, Fujiblad?),
    and can be easily adapted to EOS?
     
    Einst Stein, Oct 29, 2006
    #1
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  2. Einst Stein

    Rich Guest

    Do what other Canon buyers do, buy an Olympus OM, Leica or Zeiss WA.
    They perform far better than what Canon has to offer. And they don't
    generally have 5 stops of fall off in the corners either.
    Go here and read some of the threads.
    http://www.fredmiranda.com/forum/board/55
     
    Rich, Oct 29, 2006
    #2
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  3. Einst Stein

    Einst Stein Guest

    I have read too much hearsays. Most are not countable. I need real
    experiences from real people. I have Carl Zeiss MM 50mm/1.4, 28mm/2.8,
    and Rollei 35mm/2.8. They have have serious fall-off and some color
    shift. They are better than Canon's non-L (don;t know about canon L),
    but still in the water.

    The only thing I have that is acceptable for my personal is the
    Hasselblad 50mm. I am looking for 35mm.
     
    Einst Stein, Oct 29, 2006
    #3
  4. FWIW, I've never heard of a lens normal or wider that didn't have some
    amount of falloff wide open. Wide angles will have falloff at any aperture,
    due to geometric considerations that cannot be worked around by throwing
    money at them. It's the physics of light. All the digital vs. film tests
    I've seen show the phenomenon to be the same on film and (FF) digital.

    The good news is that unlike film, digital has a lot of latitude in the
    shadows, so you can apply quite a bit of correction if it bothers you.

    Or you can just stop down. These two are both with the Canon 17-40 on the
    5D, no vignetting correction has been applied, and don't have falloff
    problems. Any Canon prime will do just as well.

    http://www.pbase.com/davidjl/image/59225146/large

    http://www.pbase.com/davidjl/image/69033566/large
    http://www.zoerk.com/pages/p_psa.htm

    The Zork PSA adapter is available for Contax, Mamiya, and Pentax 645 lenses
    (and maybe others). It's expensive, but works. Here's the Mamiya 35/3.5 at
    near full shift at f/11 or f/16.

    http://www.pbase.com/davidjl/image/57362779/original

    David J. Littleboy
    Tokyo, Japan
     
    David J. Littleboy, Oct 29, 2006
    #4
  5. Einst Stein

    Bill Hilton Guest

    Stop down a couple of stops and you should be OK ... here's an example
    with the 24-105 f/4 L IS, which has awful MTF graphs wide open but
    cleans up quickly by f/8 ...
    http://members.aol.com/bhilton665/tests/24mm_vignette.jpg

    Everytime I get a new lens I pop it on the 1Ds and shoot wide open,
    then stopped down 1, 2 and 3 stops and quickly see the min aperture
    required for little or no vignetting ... same with the 1.3x sensor on
    the 1D M II ... this 24-105 is the worst lens I've tried but I would
    never shoot at 24 mm and wide aperture so it's not a big deal in real
    life.

    If you use Photoshop for RAW conversions you can also use the
    anti-vignette feature to clean up this kind of thing quickly.

    Bill
     
    Bill Hilton, Oct 29, 2006
    #5
  6. Einst Stein

    Einst Stein Guest

    It's time to do your own test. You don't need any special set up, just
    shoot a white wall with straight raw file.

    You can do a photoshop twist to cover up, but that's not the same
    thing.
    Stop quoting things you don't have real knowledge. Zork can't convert
    Contax 645 or Contax N to EOS. You are wasting your own time and might
    be wasting someone else's money.

    A lot of people are trusting the words you put here, So, be
    reasponsible by all means.
     
    Einst Stein, Oct 29, 2006
    #6
  7. Einst Stein

    Rich Guest

    And you think the users on those forums engage in hearsay? Why don't
    you take a LOOK
    at the equipment they use?
     
    Rich, Oct 30, 2006
    #7
  8. This summary for a Canon (non-L) EF 50mm f/1.4 in the most extreme
    corner:
    <http://www.xs4all.nl/~bvdwolf/main/foto/Imatest/LightFalloff.png>
    shows fall-off is approx. 0.4 stops fall-off at f/4.0 and smaller
    apertures at the worst, and there is additional mechanical vignetting
    at wider apertures in the order of 2 stops in total around f/1.8, and
    2.5 stops at its widest setting.

    That is only for a full frame 24x36mm sensor, 'cropped' designs show
    hardly any vignetting, as can be concluded from the following
    distribution patterns:
    <http://www.xs4all.nl/~bvdwolf/main/foto/Imatest/Vignetting_50mm.png>
    ..

    I don't know how often you shoot at say f/2.8 or wider, but it is
    mostly a minor issue at smaller apertures, and it can be corrected in
    postprocessing if it is visible at all.
     
    Bart van der Wolf, Oct 30, 2006
    #8
  9. A well-put factual counterbalance to the piffle put out by Rich.
    Impressive image, David. Interesting products. The Zork website is
    silent on prices; the LL review suggest $499 for the 645-35mm adapter in
    the US; anyone know if this is the same in Europe? The Contax G
    adaptions would have interested me very much a few years ago, but with a
    mostly digital work pattern now, I'm not too sure.

    David
     
    David Littlewood, Nov 6, 2006
    #9
  10. Einst Stein

    Bo-Ming Tong Guest

    Einst,

    It is true that Zoerk cannot convert Contax 645 or Contax N to EOS.

    The difficulty here is that while all such lenses have an aperture
    ring, the actual aperture is "fly-by-wire" and controlled
    electronically. In order for a conversion to be useful, we need to
    figure out how to control the aperture, or else you can only shoot wide
    open.

    However, I have already figured that out for you! Currently you can
    modify the 17-35, 24-85, 70-300, 100/2.8 Makro and 85/1.4 in Contax N
    mount to Canon EF mount. They will still retain autofocus and auto
    aperture after conversion. Review http://en.conurus.com/ for details.

    I am still working on Contax 645.

    conurus
     
    Bo-Ming Tong, Dec 13, 2006
    #10
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