Showcase Zeiss 50mm f/1.5 ZM C-Sonnar

Discussion in 'Adapted Lens Sample Image Showcase' started by G1 User, Jul 31, 2010.

  1. G1 User

    G1 User Mu-43 Veteran

    411
    Jul 20, 2010
    My Set Up
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    f/2.8 @ 4 feet
    This Version is optimized for f/2.8... This is the original 1924 formula in a more modern case and mount, + the T* coating.
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  2. Brian S

    Brian S Mu-43 Top Veteran Charter Member

    714
    Apr 11, 2009
    On the EP2, the F2.8 optimization does not mean much. As you are viewing through the lens, you do not worry about how the RF cam is optimized.
     
  3. G1 User

    G1 User Mu-43 Veteran

    411
    Jul 20, 2010
    What that means is that if you want DEAD sharp wide f/stop image, you use f/2.8, not f/1.5 or f/2. Zeiss built this lens to the same specs as the 1924 50mm f/1.5 Sonnar to reproduce the slight softness and glow wide open, which became the PJ favorite lens for close and personal portraits. By f/2.8, it preforms like any modern lens, and by f/5.6, it is actually sharper than 50mm f/1.4 Lux ASPH (by lens review testing). it has nothing to do RF cam coupling at all. It is how the lens was designed. And, not many people like that design, but, if you want to replicate the old style close person portraits, at wide f/stops, This is the lens to get... If you want tack sharp wide open close personal portraits you use the Planar design. It is a matter of personal choice.
     
  4. Amin Sabet

    Amin Sabet Administrator Moderator

    Apr 10, 2009
    Boston, MA (USA)
    Peter, the optimization for f/2.8 is related to focus as Brian said. This lens is designed to focus spot on at f/2.8 and exhibits focus shift at f/1.5. Some individuals have sent their lens to Zeiss for the focus to be optimized for f/1.5 so that there will be no focus shift when used at that aperture, but in that case, there will be focus shift at f/2.8. As Brian said, this is irrelevant for live view shooting (G1, E-P2, etc), unless for some reason you choose to focus with the lens at a different aperture than you plan to use for the shot. More about this here:
    Zeiss M-Mount Lenses
    Focus shift in the 50mm Sonnar ZM at close range - Photo.net Leica and Rangefinders Forum
    Comparative focus test of 2 versions of C Sonnars - Rangefinderforum.com
     
  5. Brian S

    Brian S Mu-43 Top Veteran Charter Member

    714
    Apr 11, 2009
    I have converted twelve of the pre-war 5cm F1.5 Carl Zeiss Jena lenses to Leica Mount myself, and have optimized most for F1.5.

    http://www.ziforums.com/showthread.php?t=360

    The uncoated lenses were never made in Leica mount, but Zeiss did make a few thousand of the coated lenses in Leica mount during WW-II. I have two of those.

    One of my keepers is optimized for F2, so that the DOF covers F1.5 and F4 is still usable. The other is spot-on at F1.5. This is done by setting the shim, the stand-off for the optics sitting in the focus mount.

    On my M8, the 1930s version of Sonnar, that the modern lens recreates. Wide-Open at F1.5.


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    Of course, on my EP2 the focus is at each F-Stop as the RF coupling is not used.

    My 1935 CZJ Sonnar, wide-open at F1.5 on the Canon P.

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    This lens is shimmed for perfect focus at F1.5 using the RF.

    This is with one of the Carl Zeiss Jena Sonnar "T" 5cm F1.5 lenses made in Leica mount, probably in 1943.

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    I rebuilt this lens, and shimmed it to be spot-on at F1.5. On the Canon P.
     
  6. G1 User

    G1 User Mu-43 Veteran

    411
    Jul 20, 2010
    I fully understand the focus shift that is in the lens. And shooting at f/1.5 with G1 will negate the effect, I agree. I have a Leica M5 I use this lens on also... In that case, if, I want that old time signature at f/1.5, I use the RF. But, the Lens RF coupling is not adj by Zeiss to achieve f/1.5 optimization.. It is an internal design. And, IF, you want Zeiss to optimize it for f/1.5, they adj the internals a bit for that.
    I mentioned that the lens was optimized for f/2.8 because many non-Rf users would consider that lens has a flaw.. It does not. On a Rf, you need a little understanding on using the lens for different effects on RF/DRF cameras. Or, you will be very disappointed with the results.,

    That's also why I mentioned the Planar design that IS made to sharp at f/2, for those who always expect that quality. Two very different designs, for 2 very different types of shooting wide open. And, Zeiss explains this difference too. btw, the Planar is much more popular because most want tack sharp at wide open. I like both, depends on what I want... Sharp... Put it on the G1, If I want a 1924 PJ look... I Put it on the M5... for f/1.5 shooting. It's 2 lenses in one! for 1/2 the price of buying 2 lenses.

    Thanks for the links...The photo.net is the only one I hadn't read before I traded my 50mm f/1.1 Nokton for the ZM 50mm f/1.5 C-Sonnar.
     
  7. G1 User

    G1 User Mu-43 Veteran

    411
    Jul 20, 2010
    @Brian S

    Wonderful images
    Sounds like you are handy with old lenses.
    Yes, the ZM 50mm f/1.5 is a direct descendant to the 1930 Sonnar T*...
    It can be a magical lens. I see you like Tack Sharp Wide open. I do too most of the time. I also like options.

    That little girl face shoot is really shows the bokeh of that Zeiss design... Lovely Capture.

    That last photo has that classic look too.
     
  8. Brian S

    Brian S Mu-43 Top Veteran Charter Member

    714
    Apr 11, 2009
    Adjusting the internals of the lens would mean adjusting the stand-off between internal elements, and changing the focal length of the lens. I have done that on lenses as well. It changes a lot of things, including corrections that go into the design of the lens. It is much easier to adjust for focus shift by shimming the lens, and the difference between optimizing for F1.5 and F2.8 is about 0.04mm.

    Unless you have inside information on how Zeiss changes the standoff between internal optics, everything else that I have read states that they adjust the RF cam. If they are changing the internal configuration of the optics, I would like to know what they are doing.
     
  9. G1 User

    G1 User Mu-43 Veteran

    411
    Jul 20, 2010
    that might how they do it... seems reasonable
     
  10. G1 User

    G1 User Mu-43 Veteran

    411
    Jul 20, 2010
    Back to images with Zeiss 50mm f/1.5 C-Sonnar-ZM

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