J3's CAN focus smoothly, can't they?

[SteveM(PA)]

Thanks Gabriel. I also have a '57, and through it's mass of missing screws, crumbling filter threads, and lens module that refuses to stay tight (and this one was CLA'd by Oleg) the focus is loosey goosey, but smoother than the '83.

btw, here's a pic I sent to Yuri of the back focusing, post CLA. I focused on the package of gum. There is a correctly focused shot (with summicron/sooky) in my gallery.

I'm quite sad.

 

[w3rk5]

Kim.........do you think it's possible for Steve to "Frankenstein" the two J-3 he has to get one good one?

 

[Kim Coxon]

The short answer is no. Although the optical formula stayed much the same throughout, the construction of the lens changed quite a lot. It might be possible to a "hybrid" job from 2 lens of the same series but not from this sort of difference.

Kim

Kim.........do you think it's possible for Steve to "Frankenstein" the two J-3 he has to get one good one?

 

[varjag]

Although the optical formula stayed much the same throughout, the construction of the lens changed quite a lot.

Apparently the formula changed slightly around 1953/54, accomodating the transition from Schott glass deposits to Soviet own brands. And yep, mixing optical components from different lenses is usually a bad idea.

 

[vanyagor]

In case someone would be willing to part with his/her J-3 that has backfocusing error, I would be intersted in buying it (just out of curiosity). Please send me a msg.

 

[SteveM(PA)]

Well, I got my j3 back again from fedka. Yuri had me send it directly to his house to examine, then he sent it back to Jerry, his technician. The lens barrel definitely has some angry screwdriver scratches on it now😱. The backfocusing problem is still there, and the focus, while less bumpy, is still very dry and scratchy. Oh well, I'll deal with it. And I took the focus module out and did some trial and error adjustment of the stand off ring with the help of the R-D1, and I seem to have gotten the close and wide focus pretty sharp. I don't know about infinity, but I don't much care about that.
Yuri, btw, is a true gentleman. I'm not sure what happened with this lens, but I'm going to send him a couple other lenses and see what happens.

 

[Kim Coxon]

Hi Steve,
If you have adjusted the "stand oof ring", it is most unikely that the lens will now focus correctly at infinity. 🙁 This is the main focus adjustment shim. The problem is that there is a mismatch in the "real" focal length of the lens and the RF tab "focal length". As the tab cannot be adjusted, the only way to correct the problem is to alter the real focal lenth of the lens by adjusting the spacing between the front a rear groups. This can be done on some of the earlier J3s and Brian Sweeney had a good record at doing this. On the later, particularly the black ones, this is next to impossible.

Kim

The backfocusing problem is still there, and the focus, while less bumpy, is still very dry and scratchy. Oh well, I'll deal with it. And I took the focus module out and did some trial and error adjustment of the stand off ring with the help of the R-D1, and I seem to have gotten the close and wide focus pretty sharp. I don't know about infinity, but I don't much care about that.
Yuri, btw, is a true gentleman. I'm not sure what happened with this lens, but I'm going to send him a couple other lenses and see what happens.

 

[SteveM(PA)]

Hi Steve,
If you have adjusted the "stand oof ring", it is most unikely that the lens will now focus correctly at infinity. 🙁 This is the main focus adjustment shim. The problem is that there is a mismatch in the "real" focal length of the lens and the RF tab "focal length". As the tab cannot be adjusted, the only way to correct the problem is to alter the real focal lenth of the lens by adjusting the spacing between the front a rear groups. This can be done on some of the earlier J3s and Brian Sweeney had a good record at doing this. On the later, particularly the black ones, this is next to impossible.

Kim

Riiight! 😱 Very annoying. Definitely not workable. Yuri bought the lens for $65. He offered to refund the price of the CLA (actually two CLA's) but we agreed on just the $65. So that whole thing is over. Need to have a go at another one I guess.