Will a Jupiter 3 focus OK on a vintage Canon rangefinder?

[wrs1145]

I would appreciate a knowable person replying.

Thanks,
Bill

 

[TenEleven]

Most likely not. I can not give you a 100% certain answer because there is a manufacturing tolerance involved.

Leica rangefinder base focal length is 51.6mm - Contax rangefinder base focal length (with almost Russian lenses follow) is 52.4mm. Russian M39 lenses however do follow Leitz 28.8mm spec for back-focus - so on a well calibrated in-spec Jupiter-3 infinity will be correct, and as you get closer the lens will increasingly back-focus. This is why they have a mixed reputation in my opinion, not because the glass is bad, but a lot of people do not understand this fact.

Now, since there is a tolerance in focal length some lenses will be 52.3mm.. and some will be 51.9mm - the latter will focus perfectly fine on a Leica standard following rangefinder. So it depends on the individual lens - if you can try before you buy this is the best way.

 

[Coldkennels]

Now, since there is a tolerance in focal length some lenses will be 52.3mm.. and some will be 51.9mm - the latter will focus perfectly fine on a Leica standard following rangefinder. So it depends on the individual lens - if you can try before you buy this is the best way.

I don't think I've ever seen a Soviet lens that will focus perfectly fine that hadn't already been modified by someone - every one that's been through my hands will give 1.1m on the focus scale when mounted on a Leica with the rangefinder aligned at something exactly 1m away.

Best option is to either
a) assume it won't work on a Leica
b) assume you'll have to shim it yourself to work on a Leica or
c) ask @Sonnar Brian if you can buy one of the thousands he's got stashed away...

 

[TenEleven]

I have seen several copies, most recently a Jupiter-8 that required no work and worked perfectly on LTM. There were still aluminum shavings in the mount so the chance of someone having "been there" are very slim.

Sometimes when the lens has its passport you can even see it before buying. For example I have a mid 1950ies Jupiter-3 that is specified as 51.7mm on the passport, which is within tolerance what even Leitz themselves allow, and lo-and-behold it focuses perfectly with no work required on my end besides cleaning out the hardened grease and fixing the gummed up aperture. (Edit: I should add that humorously 51.7mm is out-of-spec for the -/+1% tolerance they give - but Russia gonna Russia.)

Since I am at work I can't get to my stuff but within one minute of search here's an eBay lens that according to it's passport would likely work okay-ish.

 

[wlewisiii]

Honestly, you can find a Good Canon 50/1.5 lens which will outperform a Jupiter 3 for about the same price or less. I've been seriously looking at one lately and may yet get one this summer. You have to be careful to get clean Canon lenses (they had issues with lubricants causing fogging) but overall their lenses are far superior to the Russian ones.

 

[wrs1145]

Thank you very much!

 

[Coldkennels]

I have seen several copies, most recently a Jupiter-8 that required no work and worked perfectly on LTM. There were still aluminum shavings in the mount so the chance of someone having "been there" are very slim.

Sometimes when the lens has its passport you can even see it before buying. For example I have a mid 1950ies Jupiter-3 that is specified as 51.7mm on the passport, which is within tolerance what even Leitz themselves allow, and lo-and-behold it focuses perfectly with no work required on my end besides cleaning out the hardened grease and fixing the gummed up aperture. (Edit: I should add that humorously 51.7mm is out-of-spec for the -/+1% tolerance they give - but Russia gonna Russia.)

This actually links in nicely with a rumour I heard a while back. If you take the lens off a Drug, you'll find a regular LTM cam follower, and not the Soviet sled:



Now, as I've mentioned on here before, that's a bit odd. The Soviet "sled" allows for total adjustment of both ends of the rangefinder linkage, therefore accommodating both the Soviet spec and the LTM spec with a bit of fettling. The Drug reverting to the roller means that's not possible... so the theory goes that batches of Jupiter lenses were made in LTM spec specifically for use with this more "premium" camera. If you've found/seen Jupiter "passports" with 51.7mm given as the focal length, maybe it was intended for use with these (or even for export).

But at this point, unless we can find someone who worked in the offices of KMZ in the 50s and 60s, it's all speculation. I know I'd like to properly test a Drug to see what specification the roller cam follower is set to - if a Leitz lens is fitted and the rangefinder and lens' focusing scale agree at 1m, it'll pretty much prove this theory. I'm not about to track down a Drug for this reason alone, though!