my results with J3 and shim

[ampguy]

Based on Lynn and Brians discussions and tests with the Noktons, I cut out a round shim from a flat expired credit card and placed it between the lens and ltm/m adapter.

I stuck it on the M8, and with a ruler it was focusing down to about .7 to .8m.

Far focus still displayed accurately in the VF, and for this particular shim setup, I was only getting out to about 8 feet with barrel on infinity.

Here are some test shots, all focusing from tip of ear to eyes to nose, all at ISO 320, f1.5, and min. focus with the shim in place:

http://matsumura.smugmug.com/photos/968786153_aKGdt-L.jpg

more here:

http://matsumura.smugmug.com/Photography/Shimmed-close-focus-J3-tests/13327899_BQXt3#968785943_JLiaz

[Brian Sweeney]

Good work!

On the Jupiter-3, the internal modification to the lens are not hard for continuous focus. So- if you are handly with a small screwdriver and a file, you can get ~0.75m to infinity.

Involves removing the screw that sets the close-focus stop, seen here in the upper portion of the mechanism:

http://www.ziforums.com/picture.php?albumid=199&pictureid=1924

http://www.ziforums.com/picture.php?albumid=199&pictureid=1923

After the screw is gone, the rails for the guide pins will act as the close-focus stop. You could round out the top for the round head of the guide pin to stop farther up. It will be ~0.7m or so. Ypu need to file down a portion of the mount threads to allow the RF follower.

[ampguy]

Thanks Brian, I am not sure I'm up for the filing part, which would be ideal, but I might try a thicker shim this weekend just to see how close I can go.

[P. Lynn Miller]

Ted,

Sorry I missed this thread! So you can ignore my asking you to start a new thread about shimming the J-3

Thanks for sharing!

[ampguy]

Sure, no problem. Again, thanks to you and Brian for initiating these ideas. Most fun I've had with lenses in a long time.

Also, check out my experiments with shimming the Canon 28/2.8 ltm too. That was a lot of fun!

Ted,

Sorry I missed this thread! So you can ignore my asking you to start a new thread about shimming the J-3

Thanks for sharing!