Jupiter-3 Plus on the Leica M Monochrom

Discussion in 'Leica M and LTM Lenses' started by Brian, Mar 12, 2016.

  1. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    I have found a systematic difference for optimization of a lens on the M9 and M Monochrom, the latter has required the optics to be moved out slightly farther from the image plane. This is after adjusting many lenses for other photographer's cameras using my own M9 and M Monochrom. SO- it was not surprise to me that the J-3Plus focus is perfect on my M9 (which aslso agrees with the M240) but slightly back-focused on the M Monochrom. The back-focus is worse when using color filters, especially deep yellow through red. On a Jupiter-3 or Sonnar, a slightly thicker shim corrects the difference. This means taking the optics module out, replacing the shim, and re-indexing the aperture.

    Or... Just stick a layer of Tape on the back of the Cam. I found the copper tape that usually works did not adhere to the Brass cam of the J-3Plus, but some mylar tape did. About 0.05mm after being pressed into place, focus is now perfect from 0.7m to infinity with a Yellow-2 filter through to an Orange filter.

    25427483130_026c1b6478_b. J3Plus Test, Monochrom by fiftyonepointsix, on Flickr

    25728214205_5f8b716c7d_b. J3Plus Test, Monochrom by fiftyonepointsix, on Flickr

    25101587663_674df99198_b. J3Plus Test, Monochrom by fiftyonepointsix, on Flickr

    25101634223_a40e66569f_b. Infinity Test by fiftyonepointsix, on Flickr

    All at F1.5, with Y2 Medium Yellow filter.
     
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  2. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
  3. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
  4. Hap

    Hap Leica Place Top Veteran

    511
    Jan 9, 2016
    I wonder if these effects are noticeable on film cams??
     
  5. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    Not so much on film cameras- it has depth to it, and no one goes "Pixel Peeping". If you blew everything up to a 16x20 or so, "maybe" or use a loupe- you would have the lenses and camera bodies "Zeroed" for best use. Bill Pierce wrote about this in his forum and in his columns.
     
  6. Hap

    Hap Leica Place Top Veteran

    511
    Jan 9, 2016
    Good to know. His writings are vast so hard to search. I am thinking about following dantes advice to develop a feel for the focus depth with lens align.....even though designed for digital or non rf cameras
     
  7. Hap

    Hap Leica Place Top Veteran

    511
    Jan 9, 2016
    ....and just kludge up a ground glass to mount on my m