Jupiter 3 help

MikeLeFevre · 02-14-2005

Hello all, I got a Jupiter 3 in the mail yesterday and was trying it out on my rangefinders when I noticed a problem- the focus is off i.e. to get focus on an object 2.5m away it reads 3.5m on the Jupiter 3. I checked the 2.5m distance was correct, and with my Jupiter 8 and Industar 61 which work fine. I even tried different bodies but it still does the same. When I look at how much the inner tube of the lens that touches the rangefinder cam moves it doesn't seem to have as much travel as the J8 and I61 when it is at full extension i.e. it doesn't stick out as much from the lens body when it's at full extension. So my question is does anyone know what's happening? Before I try the greaseproof paper focusing trick.
M.

ddutchison · 02-15-2005

Mike, I'm sorry I can't be more specific here, but some time ago I came upon a web site devoted to the J-3, and unfortunately I didn't bookmark it.

I do remember reading that this lens often has to have its focusing mount adjusted, and that it's designed to to allow this (I believe jewlers screwdrivers were all that is needed). So if it is in fact not focusing correctly, it may be an easily solved problem. Perhaps someone else here will be able to give you the link (the page had detailed instructions), or you could try asking in the Classic Camera Repair forum..
http://www.kyphoto.com/classics/forum/

also
http://www.beststuff.com/forum/index.php?f=25

MikeLeFevre · 02-15-2005

Thanks for the info guys, I'll look out for that web page.

Brian- I found your other posts on the copper tape you use- what is it usually used for? i.e. what kind of places would stock it?

Regards
Mike

Pherdinand · 02-15-2005

Might be a result of a sloppy relubing action of somebody who did not care. The difference is so much, that it indicates not a small misalignment but a focusing helicoid that was disassembled and put back together in a wrong position.
Is every other distance ok? Can you focus at infinity, on the scale? Does it STOP to rotate after infinity on the scale? How about the closest focus (same questions)?
If the answer is "no" to any of these, i'm quite sure it's the bad reassembly. Especially if it focuses smooth, not sticky - thus if it had a relube done.

FrankS · 02-15-2005

Based only on what I've read on this issue (and not on first hand experience) I'd agree with David and Pherdinand that the problem is a result of improper reassembly. (The observation that a smooth focussing action would indicate a recent disassembly for relubing is very astute.) Might as well take it apart and put it back right.

MikeLeFevre · 02-15-2005

Thanks for the further suggestions. Just looking at the scale it focuses badly at every other distance too (I haven't put something on the film plane yet and had a look there). I can't get the chimney of the house next door in focus with the rangefinder i.e. ít would need to rotate more past infinity to do so (it goes about a mm past but that's it, it goes about 3mm past 1m at the other end and overall rotates smoothly).
M.