Pentax K to M42 adapter

Discussion in 'Film Camera Forum' started by ReD, Sep 9, 2015.

  1. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    The Cosina C1 is a pentax K fitting (ie old film type)

    I want to mount M42 extension rings & lens to it

    Looking up adapters I see all sorts of K numbers & I'm not sure what is relevant to the Cosina C1.

    Also if anyone here is looking to offload an adapter I may be interested.

    Any advice appreciated
     
  2. Luke

    Luke Super Moderator

    Nov 11, 2011
    Milwaukee, WI USA
    Luke
    to be clear, Roger.... you're looking for an adapter to mount a K-lens to an m42 body? Or is the other way 'round? You want to mount screw mount lenses on a K body?
     
  3. Kompaktkameratyp

    Kompaktkameratyp SC Rookie

    15
    Jul 6, 2010
    You essentially need the M42-PK adapter, which comes in a couple of versions. I'd recommend the original Pentax adapter, if you can find it: it is manufactured very nicely and mounts/unmounts without trouble. I'm not saying the other makes don't work, but sometimes you hear funny stories...

    The other thing you need to pay attention to: M42 lenses have an aperture mechanism that works by pressing in a little pin on the back side of the lens. This aperture pin is not depressed by the M42/PK adapter (nor would it be by extension rings, typically). Therefore, lenses that work *only* in auto aperture mode will not stop down on the Pentax K mount camera. You *can* shoot these lenses wide-open, and you *can* convert Auto lenses to manual operation, but the best possibility, imho, is to buy M42 lenses that allow manual aperture operation by a manual/auto switch: You focus the camera with open aperture, then press the auto/manual switch, which takes the lens to shooting aperture, then you click the shutter (and Kodak does the rest, as the story goes)...
     
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  4. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    To be Clear Luke I want to mount M42 screw lens etc to a K mount fitting

    Thanks Kompaketc - The Cosina C1 ia all manual camera (no auto anything) - one of the main reasons is to use the M42 extension ring as part of a pinhole assembly so definitely not bothered with fiddly controls.
    My only other screw mount is a manual M42 Optik Meyer 30mm however I already have a Tamron Adaptall 28mm with a K adapter so less likely to use the Meyer
     
  5. Luke

    Luke Super Moderator

    Nov 11, 2011
    Milwaukee, WI USA
    Luke
  6. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    Thanks
    Cost is of primary consideration here and the original adapters are way way more than the Cosina I bought - as far as pinhole (which will be likely the main use) I could simply cut card & fit direct to the K mount - I used this same technique before on my Fuji STX1
    I'll give this a try I think rather than risk jamming up a fine camera.
     
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  7. Kompaktkameratyp

    Kompaktkameratyp SC Rookie

    15
    Jul 6, 2010
    So you're trying to do close-up pinhole photography? Interesting... Maybe the best solution in this case would simply be to get Pentax K extension rings (they are dirt cheap, afaik) and get a Pentax body cap, drill a little pinhole in it and tadaa, pinhole setup? :) The Meyer 30mm alone may not be worth going for M42 -- especially since the Adaptall 28mm (which I have myself) is a pretty darn good lens...

    (Don't get me wrong though: I love the option of getting old M42 lenses for next-to-nothing, and experiment with their looks. Just not what you seem to have in mind though)

    Oh, and btw, the name "Kompaktkameratyp" translates into English as "compact camera guy" -- I think you just have to love the German language for those unbelievably large words it builds... (then again, the English equivalent is even longer, innit?)
     
  8. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    Thanks Herr Kompaktkameratyp -a very good idea about the Pentax rings
    I've looked a bit more closely at the K mount - ideally I need a whole flange to seat the pinhole card nicely & the K flange is in segments which is not ideal
     
  9. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    Update
    Received a Pentax K Body Cap today - converted it to Pinhole & took a few photos as a test run
    results if working to follow
     
  10. Kompaktkameratyp

    Kompaktkameratyp SC Rookie

    15
    Jul 6, 2010
    Yes, please post some pictures you take with that setup -- and maybe a pic or two of the camera/pinhole itself as well? Interested in how large a hole you drilled (and what the image "look" is like with that diameter).
     
  11. Kompaktkameratyp

    Kompaktkameratyp SC Rookie

    15
    Jul 6, 2010
    ... oh, one more thing: I have one of those Lensbaby thingies which can load a pinhole plate as well. What's more interesting: you can also load differently shaped pinholes, and even plates that have multiple pinholes and such. Used that with digital cameras for experiments, and while many results are, err, strictly "experimental", some were really, really nice. Maybe if you want to go all out with you pinhole idea, make the pinhole section itself removable, so you can experiment with that? Some prior experimentation with a digital camera might be necessary, though, if you don't want to burn too much film...
     
  12. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    Thanks - I'll have to check out the Lensbaby stuff - ideally I would like a digital camera with interchangeable lenses in meantime its the Cosina
    Here is a photo already posted on another thread & yes designed for alternative pinholes

     
  13. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
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  14. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
  15. Kompaktkameratyp

    Kompaktkameratyp SC Rookie

    15
    Jul 6, 2010
    That appears to be a very sound construction -- and you cannot argue with the results, either: Very nicely done, indeed!
    Note, btw, it's not either the Cosina or Lensbaby -- you can get Lensbaby stuff with the Pentax bayonet, and go on using the Cosina -- and/or get a cheap old digital Pentax body, which go for very little (e.g. K200D, very nice camera, rugged and weather-sealed, yet only around 100-150$). Yes, they are lower resolution than todays monsters, but of course they are easily more than adequate for the kind optical resolution a Lensbaby will provide (and, some will argue, for any other lens, too). Such is the beauty of the Pentax bayonet, actually: You can swap between analog and digital camera pretty seemlessly (except the digital are all APS-C only, so far) and use lenses from the 70es onwards...
     
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  16. ReD

    ReD SC Hall of Famer

    Mar 27, 2013
    Cosina Pinhole BW Conversion Cropped and tweaked. The original was softer and less crisp than this.
    Compares well against an older shot I did with the X10 which was processed heavily to get an old fashioned film blur shot


    21091678284_8221834cc9_b.

    img pin 608 Cosina General Market BW
    by Roger Evans, on Flickr


    X10 version


    15459964707_fd07bc57ee_b.

    GM2 BW
    by Roger Evans, on Flickr ​