Classic Manual Lenses with Delicate Focus Control

Discussion in 'Classic Manual Cameras' started by christian_fox, Sep 20, 2014.

  1. I have enjoyed sampling classic manual cameras and their associated lenses. It has been quite a ride, especially sharing it with users and restoration folks that have embraced this interest for decades, and have a comparative feel for some of these cameras. I favor the earlier models of the modern era, such as Nikon's first SLR, Canon LTM, and SL2. A few electronic cameras are interesting as well, like the F4, RX, and R8.
    There is considerable available literature on lens quality, but I am very sensitive to the lens ability to focus loose and buttery smooth, perhaps it is because I demand it so much when I use nice binoculars daily. With binoculars, I gain far more information when I constantly roll the focus wheel on both sides of perfect focus, especially with 10x magnification. My favorite focus wheel is the Pentax Papilio 8.5x21, used only for 18 inches to 4 feet. With this binocaulrs, a Praying Mantis upclose becomes a scary creature indeed. Beyond 3 feet, the Leica Ostrich 8x20 works fine and offers excellent views with good diopter settings, although for most users, compacts require considerable skill. The Ostrich skin and metal body of this Leica compact has no comparison in feel - it is truly a work of art beyond specs.
    In comparing a few lenses (LTM, C/Y, Nikon F (NAI and AI), M42 TAK, and momentarily a Leica R), I was surprised by a remarkably smooth and intricate focus ring on a 50mm Yashica ML lens, while some of my Nikons and LTM can get quite stiff, presumably due to aging. I have never tried a modern CV lens, but I have read that they are smooth and offer sensitive control.
    It makes me curious, from your experience, if certain lens brands or models of an era are known to be unusually smooth in focus control compared to most lenses.
     
  2. SCL

    SCL

    I'll add to the list the Canon FD lenses.
     
  3. I think there are a good many lenses out there that would qualify. I believe (at least for me) it would be easier to name the ones that are not smooth. Among lenses bought new, the Phoenix (Cosina made) 100mm f3.5 macro does not have smooth action when focusing, but it is optically quite good. I've found that among independent lenses, the Tamron Adaptall SP series to be quite smooth.
    Interesting comparison to binoculars, BTW. I have several pairs ranging from budget Bushnell 10x42 (adequate, but not great) to Bushnell 7x26 Elite (smooth focus, good performance), two pair of Orion (8x42 and 10x50) which perform well and a pair of water resistant 6x30 Leopolds that I often take to sporting events. I still have my old Empire 7x35's that I bought in high school.
     
  4. By a strange coincidence I was looking through an old copy of Modern Photography, December, 1983 last night and noted an article on a related topic by, of course, Herbert Keppler (how I miss his columns).
    As is so often the case, Keppler got it right on the topic of apparent crispness in focusing:
    1. First, lenses with large apertures produce far less depth of field at the same focusing distances as do other lenses of like focal length but with smaller apertures.
    2. Another photo herring is the focusing mount itself. Given two lenses with the same focal length and maximum aperture, the lens with the shortest focusing scale distance between 3 ft. and infinity will appear to have more crispness and snap. Why? Because for the same amount of focusing mount turn, the lens travels further in and out of focus. This may give you a sense of crispness and snap but such a helical mount may not provide you with the most accurate focus . A lens which shifts focus very slowly for small increments of lens mount turn can offer more precise focus than the swift, close focus to infinity type of lens mount.
    3. Of course the maximum aperture of the lens, as already described, also adds to or subtracts from the old crispness and sharpness game. For instance, take an 28mm f/2 lens with a very short 3 ft. to infinity focusing ring turn, and it will appear in the viewfinder to be the most crisp and snappy you've seen.

    Keppler-SLR Notebook MP 1983-12 pp. 64-5
    00cqCJ-551226784.jpg
     
  5. The weight of the glass that moves during focussing factors in too. Loose and buttery smooth focussing action and moving a kg of glass back and forth do not go together.<br>Not a one-brand-vs-another-brand issue. It has to do with what lens, what focal length, what speed, how much glass, how is the lens focussed (unit vs element/group), and stuff like that.
     
  6. Do not forget the effects of lubrication.
    We all know the usually stuck focussing rings on Agfa cameras and some others.
    Also, most greases change their properties during the decades, and a lens which originally might have focussed very smooth may turn into a very hard to focus lens over time.
    I have regreased quite a few focussing threads and made very good experience with light silicone grease. It will not degrade over the years and usually gives a very smooth focussing feel. Only exception was an old russian LTM lens. On this lens, due to its mechanical design, you actually move three different threads when focussing and the light grease was still too stiff. Finally I removed the new grease again as far as possible and used some silicone-based oil. The lens is still a bit stiff but can be focussed without problems.
     
  7. The technical response to this inquiry is very interesting - I did not conceive so many variables to a lens and focusing. I suspect Winfried's lube issue is a significant factor with some of my samples.
    I was hoping that someone would reveal a manufacturer that gave this some thought and designed a distinctive focus mechanism with unique bearings or something like that.
     
  8. Focusing helicals are lubricated (these days) with "damping grease", which comes in a variety of viscosities so that you can get the "feel" that is desired.
    The materials of the helical matter. Some metals naturally move smoothly against each other, some metals don't. Steel and brass are naturally self-lubricating. Aluminum and brass is also a good pair. Aluminum on aluminum can be good or bad, depending on the alloy, and surface finish (anodizing).
    The RE. Auto-Topcon lenses for Topcon cameras have aluminum helicals, which are noted for very nice feel, but the feel certainly is dependent on the lubrication. On the other hand the Zeiss Contarex lenses have aluminum helicals, but with a thin dark anodized finish. If that finish wears through, they self-destruct by welding the threads.
    There have been many cases where the lubricants used years ago proved to be corrosive the the helicals. The classic example is the Agfa "green glue," which was a grease that reacted badly with the brass. The Contarex lenses had a lubricant that failed over time, combined with a poor choice of aluminum alloy.
     
  9. Equally maintained of course:
    Contarex lenses get my vote, they have a true precision "ball bearing" feel.
    For a great feel that is derived from "grease" rather than pure precision
    (Regardless of "weight of the glass", as demonstrated by the silky Carl Zeiss 28-85mm f/3.3-4.0 Vario-Sonnar T* MMJ Contax),
    I give it to Zeiss "Contax" C/Y lenses...
    00cqQF-551266584.JPG
     
  10. "The 300mm f/2.8 has probably the sweetest and most well damped manual focus ring, and a surprisingly short throw. The result is that images snap into focus with startling clarity."
    Shutterbug, january 2003, about the Carl Zeiss Tele-Superachromat f/2.8 300 mm.
    I was never rich enough to try this lens. Only played with it very briefly at the Photokina when it was introduced, and frankly can't remember who smooth it was. It should be though, since Zeiss made it a point to have this heavy lens move effortlessly. But maybe it's a dog when focussing is concerned. Anyone have any experience with this lens?
     
  11. Now I must confess that I have a lot of lenses, way too many! Thought that I would just compare a few after reading your post,and the result surprise me a little.
    Although there were many that were very good, the overall standout in my collection are the various Super Takumars, especially the 50mm 1.4. Also of note are the newer CV Voigtlander lenses, particularly the 28mm Ultron and the 75mm Heliar.
     
  12. Difficult to answer because i have way too many cameras, but in general i'm very happy with the focus feel of AI and pre-AI Nikkor lenses.
    I also had a Canon New FD 200/2.8 with IF (internal focusing) that had a really smoooooooth focusing action...
     
  13. I also like the early pentax
    super takumars. Especially the
    ones with the scalloped focus
    rings. I also like the Minolta mc
    line for their excellent build
    quality.
     

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