Lens mount L39 & M39

Discussion in 'UK Photography' started by John Orrells, Feb 11, 2007.

  1. John Orrells

    John Orrells Guest

    Are bayonet lens mounts L39 and L39 the same?
    Thanks for any help
    John.
     
    John Orrells, Feb 11, 2007
    #1
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  2. John Orrells

    Trev Guest

    There both screw, metric 39 x1mm pitch

    M bayonet Fit is just that
     
    Trev, Feb 11, 2007
    #2
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  3. John Orrells

    John Orrells Guest

    thanks Trev silly me! I did mean to say screw lens mounts L39 & M39 are
    they the same?
    I must put my mind in gear first before engaging keyboard!
    Regards.
    John.
     
    John Orrells, Feb 11, 2007
    #3
  4. John Orrells

    Tony Polson Guest


    Both have the same thread, however they are two different mounts,
    because the lens flange to film distance differs substantially.

    M39 mount was used by the manufacturers of the early Soviet SLRs among
    others. The lens flange therefore had to clear the reflex mirror.

    L39 mount was used by Leica and other rangefinder camera
    manufacturers. There is no mirror box so the lens flange could be
    placed much closer to the film.

    M39 and L39 lenses will mount on cameras designed for either mount.
    However, you will not be able to obtain focus if you use the lenses on
    the wrong type of camera.

    In other words, L39 rangefinder lenses will not obtain focus on M39
    SLR cameras, except for close macro workand M39 lenses for SLRs will
    not obtain focus on L39 rangefinder cameras at all.

    Beware the very cheap M39 to M42 adapters offered on eBay. They are
    designed to mount M39 SLR lenses on M42 mount SLRs. Any L39
    rangefinder lens used with an M39 to M42 adapter on an SLR will only
    be good for close macro work.
     
    Tony Polson, Feb 11, 2007
    #4
  5. John Orrells

    John Orrells Guest

    Tony Polson wrote:


    thank you tony, great help
     
    John Orrells, Feb 11, 2007
    #5
  6. John Orrells

    John Bean Guest

    M39 is 39mm diameter and 1mm pitch. L39 is also 39mm
    diameter but is 26TPI (threads per inch) pitch.

    The difference is small but can (and does) make some lenses
    difficult to mount on some bodies. In particular most
    Russian lenses are M39 whether intended for use on SLRs or
    RF cameras.
     
    John Bean, Feb 11, 2007
    #6
  7. John Orrells

    John Bean Guest

    They don't Tony. The difference is slight but real.

    M39 is 39mm x 1mm, L39 is 39mm x 26TPI.
     
    John Bean, Feb 11, 2007
    #7
  8. John Orrells

    Tony Polson Guest


    Thanks, John. I didn't know that.

    But between the two of us, I think we have the subject covered. ;-)

    Thanks again.
     
    Tony Polson, Feb 11, 2007
    #8
  9. John Orrells

    Bandicoot Guest

    [SNIP]
    Presumably they could if fitted with an appropriate length extension tube?
    Not very useful in general though, not being coupled to the rangefinder.


    Peter
     
    Bandicoot, Feb 12, 2007
    #9
  10. John Orrells

    Tony Polson Guest

    Yes, of course. I did not feel a need to mention that. ;-)
    True, however I use an M42 20mm Carl Zeiss Flektogon on my Leica M
    bodies without problems. Obviously there is sufficient depth of field
    to cover minor scale focusing errors.
     
    Tony Polson, Feb 12, 2007
    #10
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