Leica Jupiter-3 Plus on the Leica M Monochrom

BrianS

Legend
Jul 7, 2010
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.

J3Plus Test, Monochrom
by fiftyonepointsix, on Flickr

J3Plus Test, Monochrom
by fiftyonepointsix, on Flickr

J3Plus Test, Monochrom
by fiftyonepointsix, on Flickr

Infinity Test
by fiftyonepointsix, on Flickr

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

BrianS

Legend
Jul 7, 2010
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.
 

Hap

Top Veteran
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
 

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