Best Apertures for Zeiss Optical Formulas (Contax + Contarex)

Discussion in 'Classic Manual Cameras' started by jtayloreckstein, Feb 19, 2008.

  1. I have been struggling to find the kind of information that I like to know about my lenses through my normal routes (mainly the Internet).
    I'm trying to figure out how the following lenses behave at different apertures. I have rather limited experience with testing the lenses as putting a 36 exposure roll on a Contax or a Contarex seems to take longer than expected.
    I threw in a roll of Tri-X, exposing around 1300 to be developed later in Diafine, and then I realized I know even nothing about how these lenses behave above f/8. Kinda worried about strange defraction, etc. if I venture outdoors.
    No lens tests necessary (always welcome), casual experiences greatly appreciated. Any related lenses and your experiences welcome.
    f/2.8 35mm Carl Zeiss Opton Biogon
    Very sharp, but there seems to be a magical range between f/4 and f/5.6 where it really shines. Have not tested it past f/11, what's it like?
    f/3.5 50mm Carl Zeiss Jena Tessar Post-war collapsible
    At first I thought it was an unimpressive lens, as I was shooting wide open. As I found out, shooting wide open somewhere between f/11 and f/16 rendered amazingly sharp results. Any experience near f/22? (my f/2.8 Contaflex Tessar at f/22 was somewhat disappointing, maybe related to leaf shutter problems though)
    f/1.5 50mm Sonnar (coated, believed to be Post-war)
    I saw more modern reviews of the lens. Still unsure how I feel about the lens as it has a lot of character, but can feel soft at times. Have an uncoated 135mm f/4 Sonnar, seems to operate about the same.
    f/2 50mm Planar for the Contarex
    Had some good experiences wide open, but how does it handle the smaller apertures?
    ...and why not. f/1.8 53mm Helios (uncoated)
    Despite not having the same degree of contrast as the others, a fun lens. Any other experiences? If I were to go outside, I would be tempted to throw on the Tessar and shoot at either f/16 or f/22... but that's about as far as I've gotten.
    Give me your experiences, anything!
    Also, I have not experienced any issues with UV wash out on these lenses (on the limited shooting I've done). For shooting B&W, I just found out a yellow filter is often considered the first step, is this true? Coating change this any? I feel like a dummy, after having shot B&W for a while now... On my Nikon, I left the Haze 1 on alot of the time.
  2. Why don't you just try and have your own experiences with all these lenses?

    Ok, as you've asked: As a rule, Tessar-Type lenses need to be stopped down two stops for maximum performance. The 3,5/50 Tessar is a gem indeed.

    Like all old wide angle lenses, the Biogon 2,8/35 is soft at the edges of the frame wide open; stopping it down a bit takes care of that, stopping it down a lot causes diffraction effects that degrade the picture a bit. I'd say best performance is at f8, maybe f4-5,6, if the edges don't have to be critically sharp. Still, it is getting old by now, and there are worlds between it's performance and that of a modern lens such as a Summicron Asph 35.

    I don't know why the 1,5 Sonnar has such a great reputation. It is ok for an early superfast normal, but the performance of any slower Contax RF lens (Sonnar 2/50, for instance, or your Tessar) is better at comparable stops in my experience. A vintage Voigtländer Nokton would also be a better choice.

    The 4/135 Sonnar - at least the coated post-war one - is one of the best performers of all the Contax lenses; it is better than any 135 Leitz made for LTM. It's sharp wide open and at an optimum at f5,6.

    The Planar 2/50 is a very capable performer even by today's standards, but like most f2 double gauss lenses it has a performance peak between f4 and f 5,6. It can be used wide open without problems.

    All this is quite academic - your photographic techinque and your artistic vision is what really counts, and you'll be able to take great pics with all lenses you have, but you may want to use the time shooting instead of spending it at the screen asking about your gear.
  3. Optical performance improves as a lens is stopped down, while diffraction effects degrade the image more. Unless I am sure there is a better "sweet spot," I usually try to shoot at apertures of f:6.3-8.0 for all of my 35mm cameras and lenses. It seems like a good compromise combination of speed, depth of field, and acutance. There is a lot more to best lens performance than highest resolution, you know.
  4. Diffraction! That's the word I was looking for. Not too concerned with resolution or sharpness. It is what it is. I have bad memories of using 800 speed film at a get together at the state Capital and being forced to f/32 for the correct exposure (body with a slow shutter speed). Everything was in a haze, very hard to get a half-way decent shot out of there.


    I don't meant to sound like a hermit. My pile of things to develop in my darkroom is piling up, and I am not using these lenses much anymore. I am pursuing a few ideas of mine on a more modern system and wanted to make sure I wasn't making things harder on myself.

    Please forgive me! I'm stuck at work at the moment and I wish I could be somewhere shooting.
  5. I have put most of the Contax lenses on my collimator, and used them myself and here is what I think.

    Firstly and foremostly, the range finder has got to be in good adjustment, before any comparison can be made. Barring any mal-adjustment, I would give the following recommendations.

    Zeiss Sonnars: I like the post war chrome 1.5 as it is probably the best overall lens put on a 35mm range finder in the 1950's. I have done side by side comparisons with this lens and Leica Sumatar, Summalux, and Summarit, in all cases the Leica lenses where slightly sharper, but the Sonnar gave more accurate color and better contrast. As to what f:stop is best. I like 8-11. At 5.6 most will give 125 line pairs per mm on my collimator, but they start to suffer some flair. I have shot them at 1.5 and will flair quite a bit with bright lights in the frame. Early lenses will go to 22, but later this was limited to 16 as performance drops quite a bit at 22 and above.

    The Post War Tessar is a good lens, and I think is as sharp as the Sonnar at 11-16, however it is better at 22. Flair is not an issue with this lens at 5.6 and below, but the sharpness will drop off below 5.6, and be practically useless. On my collimator my lens did 120 line pairs per mm at f:5.6. Oh, I think this is probably the only Tessar put on a 35 mm camera that I truly like to shoot.

    The Biogon is a truly awesome performer. I have shot it on a Nikon S2 along with my Cosina Voigtlander Skopar, and the Biogon is hands down the winner. They both have equal sharpness, however the Biogons color is much more accurate, and gives better tonal gradation. As for best f:stop, try keeping it above 8, and I think you will be happy. My Biogon only got 100 line pairs per mm on my collimator, which was just as my CV did.

    The 135 Sonnar is a great lens. Coated or uncoated it will give a stunning print when stopped above 5.6 and delivers stunning color and contrast, even in the uncoated version. That said, flair can be a problem so keep a hood on it and try not to shoot it below 5.6.

    Not mentioned is the 85mm f:2 Sonnar. This is the lens that has most impressed me in the last few years. Sharp as a tack, great color, good contrast and nice and fast. Mine gave 125 line pairs per mm, and gives absolutely perfect skin tones, and can make the sky in an ektachrome look almost perfect. I have shot mine from f:2-22 and I like it best at 8-11. Despite my lens being an uncoated version, it had little of the flair problems one might expect, and with all the other positives, why spend the money for the post war version. I did a comparison with this lens and the 90 Elmar, and Sonnar won hands down in every category.

    If I were you I would stick with the Contax, and forget about getting a more modern camera. As a professional repair tech that works on Contax IIa/IIIa cameras, I can say with complete confidence, there is no better made camera than the Contax.
  6. Assuming that the lenses are quite good, then your governing quality relates primarily to diffraction (secondarily to flare characteristics). Having tested 2 or 3 hundred or more fine reputation lenses with fine quality films the area in which the resolution starts to be a problem is with an aperture diameter of about 3mm (we don't care what the f stop is), at their optical best, diffraction is the controller of sharpness.

    That doesn't mean that I don't use lenses below that level, with my WA 90mm I often shoot at f 45 or below, and my 65 at 32 or below. Both are at about 2mm aperture or less. With chrome film the contrast makes them look great, with negative films I can tell the difference a couple of stops wider. The contrast of chrome is about 2.75 times that of of normal negative films.


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