My J-3....I think I got it.

[gb hill]

This is a Jupitar 3 made in 1963. When I got it the lens was front focusing bad. Brian Sweeny told me to use a thinner shim to narrow the distance of the rear element to the film plane. I finally got around to making a shim for it. This is around f2 to wide open on my Bessa R. I know I should write this stuff down. Anyhow I'm happy with it.

 

[payasam]

Good sharpness, good out of focus areas.

 

[Sonnar Brian]

Looks good to me!

It's amazing what a small difference in shim thickness will do to a lens.

 

[gb hill]

Thanks for the help! I think this is going to be a favorite.🙂

 

[payasam]

I've grown quite fond of mine. Its performance is impressive for such an old design. I was wrong (other thread) to have held it responsible for what was actually the work of a perforated shutter curtain.

 

[robin a]

Ya done good....................Robin

 

[like2fiddle]

That's a very impressive lens. What did you make the shim out of? I've thought of trying to use aluminum foil, but it seems as if that may be really difficult to work with.

 

[ferider]

Great, GB, looks good to me.

Roger, I cut shims with scissors from empty coke cans. I like them being metal and this works well.

Cheers,

Roland.

 

[raid]

Great, GB, looks good to me.

Roger, I cut shims with scissors from empty coke cans. I like them being metal and this works well.

Cheers,

Roland.

GB: Your results look excellent. You have done your job very well. I wouldn't know what to do.

Roland: This is a good idea!

 

[cysasam]

Hi,

Doew the front focusing happen with all cameras? What about a FED 2 or a Zorki 3? Thanks!

 

[payasam]

Roland, are not soft drink cans some sort of aluminium alloy?

 

[Sonnar Brian]

Hi,

Doew the front focusing happen with all cameras? What about a FED 2 or a Zorki 3? Thanks!

It's really hard to say, and I believe the lenses were meant to be shimmed to the individual camera. Most J-3's that I've seen back-focus on a Leica standard camera, and a few have front-focussed. About 8 in 10 required some sort of adjustment, usually within 0.2mm to put them spot-on. That last one required less than 0.1mm, but it shows when used wide-open.

 

[ferider]

Correct, Mukul, an aluminum alloy, I believe.

Roland.

 

[like2fiddle]

Roland,
Thanks for the tip on the Coke can; I rarely drink soda, but this gives me an excuse to indulge😀

 

[johannielscom]

I once shimmed a Canon 50-1.2 with thick sewing cotton thread. Trial and error approach: wind a meter of thread, reassemble and check, disassemble, cut a new thread with 10cms extra length, etc.

It worked fine and I liked the old feel of 'shimming' like this. I got it spot-on, although that took some time.

 

[gb hill]

I used a hard plastic & cut it with scissors then trimmed away the center with an exacto knife. I like the soda can idea but the aluminum is paper thin & I probably would of had to make 2 or 3 shims stacked to achieve the same thickness, besides I can picture slicing my finger trying to make one.😀