Advice on using a Zeiss 50mm1.5 C Sonnar ZM

Discussion in 'Leica and Rangefinders' started by lewis_henning, Mar 31, 2012.

  1. Hi
    I've just very very recently bought an M6 and a Zeiss 50mm1.5 C Sonnar ZM.
    I'm happy with the lens, I only shot 1 roll of film and got it back so far and I have found the results to be quite interesting, different to an SLR (which I have been used). Not super sharp but this could be because I'm still getting used to using a range finder.
    I had read some mixed reviews about the lens but decided to go with it. When I bought it (new) from the the shop, they said it had been altered for f1.5. I'm new to range finders so I'm still learning the quirks about them.
    I guess what I's like to know is...
    1. How do I tell if it has actually been altered for f1.5 with out doing loads of test shots?
    2. If it has been altered for f1.5 is still going to be sharp at other apertures?
    3. Can some explain about the focus shift? I've been reading up about it but still little confused.
    4. Can anyone advise the best way to use the lens, which apertures are going to give the best results?
    I'm sort of thinking whether I should have bought a second hand Summicron instead... It was a 50% - 50% choice. One could argue that asking all this is a waste of time, I should just get out there and use... Which is what I intend to do but I would like to know how the lens works so I know how to use it well.
    Many thanks
  2. Lewis, the only answers to your questions will be test shots. They alone will speak of your lens.
  3. I will try to explain the focus shift.
    It has something to do with spherical aberration. This means that light rays from the outer zone of a lens element have a different focus point than those coming from the inner zone.
    So you do not have a clear focus point when the lens element is used wide-open. There is a point (or plane) of maximum sharpness, i.e. where the light ray bundle mixed from rays from the outer zone and inner zone has a minimum diameter.
    If you stop down such a lens element, of course the light rays from the outer zone will be missing. So the point (or plane) of maximum sharpness is determined by the light ray bundle from the inner zone only, and will be at a different distance.
    A photographic lens does not use a single lens element but several of them to correct optical errors, of which spherical aberration is just one. The Sonnar lenses with f/1.5 had a lot of focus shift right from the beginning, that's why the aperture scale on old sonnars goes to f/11 only. Beyond f/11, the focus shift would have been noticeable. Obviously, in today's f/1.5 Sonnars, a similar optical design was used, but they did not dare to sell a lens with limited f-stop range. So you have to live with that focus shift when using the lens wide open, or have it modified for optimum sharpness wide-open and focus shift when using the lens stopped down.
  4. Roger Hicks has an excellent article on the lens including a commentary on focus shift - google rogerandfrances to get to his website.
  5. Good advice from Mark. There is no way to tell whether yours is adjusted for 1.5, even with test shots in my experience. I
    found my tests quite ambiguous. I have had no practical difficulty from focus shift. It is the most marvellous lens. Roger
    Hicks has it as his standard and I have gone weeks with just that lens on my camera. The idea that this is a specialist
    lens is silly. It is very well made, sharp at all apertures, smaller and lighter than a Summilux. It is balanced beautifully on
    an M5 or an M9. The gradation of tone on Rollei Retro 100 with f5.6 is beautiful. The bokeh and sharpness of the subject
    at 1.5 and 2.0 are fantastic. This is my one indispensable lens.
  6. Lewis, congratulations on the M6 and Sonnar.
    How are you finding the rangefinder experience?
    I wanted the Sonnar as well, but couldn't find any at the time, but have the wonderful Planar.

    If I'm not mistaken, what they meant at the shop, was that at f1.5 the focus is as it should be.
    As for the rest, I think the gentlemen here have given excellent advice :).

    Please post some pictures from the Sonnar, and enjoy! :)
  7. Thank you all for your in depth
    responses! Extremely detailed.
    Espically Winfried for taking the time to
    type all that. I'm pretty sure I
    understand now.

    I think I'm just going to shoot lots and
    see what I get! Best way I think. Just a
    bit more costly.

    I'm debating whether or not to get the
    hood. It's £70! Is it worth it I wonder,
    like I say, I've only just got the set up
    so I can't tell yet if I need it. At the
    moment I've just used my hand as a
  8. I have the 50/1.5 Sonnar ZM as well as four versions of 50mm Summicron; the collapsible, DR, V3 and V4 with tab.
    No matter whether the Sonnar was optimized for f1.5 or f2.8, focus shift exists. The easiest remedy in wide apertures is to move your head two inches backward after focusing before pressing the shutter button. For any distance longer than 2m focus shift can be ignored.
    Characteristics: Those familiar with the Summilux 35/1.4 pre would point out to the similarities in the first two apertures; full of coma and chromatic aberrations. Sonnar bokeh is rather unique in photography, abrupt changes from focused to out-of-focus zones make you think it's longer than 50mm; none of the Summicrons -inluding the collapsible- can approach this characteristic bokeh. Sharpness: I have tested it only on film Leicas, for digital refer to Steve Huff's test on the M8. Starting with f2.8 sharp with some fall of near to corners like the collapsible, f5.6 to f16, perfectly sharp rendition for film. The Sonnar has a characteristic signature one can start noticing after some dozens of rolls; a perfectly natural perspective as if looking out of an open window, just like a picture out of a reproduction lens. A certain brilliance by not being harsh (similar to the brilliance of some Hasselblad lenses however in a small scale) .
    Being the modern version of the classical Sonnar with some slight modifications, it rather is for those looking for distinct signature to complement artistic or aesthetical concerns. It is out of the conventional category of the 50mm lenses, however some Nikon and Canon rangefinder lenses have been based on the same design. Once you start "mastering" its use, you love it. It's my favorite 50 for film since the day I tried it and way different than my other Sonnar: Sonnar Opton 50/1.5 on a Contax IIa.
    Hope this help.
  9. beautiful lens rendition. mine is f/1,5 optimized, too. i find that this is best for the way I like to shoot, for in the rare circumstances I use the lens at f2 to f4 (any more closed down, DoF compensates for the shift) and only when close up that I must remember this one simple thing: to lean backwards 3". Everything else works normally.

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