Wulfthari
Well-known
Maybe I should just give my Jupiter-3 some love and sent it in for a service, have it adjusted properly and have the missing screws added? I do like that lens, but it makes me worry while out shooting sometimes... 😛
The answer is yes, the J-3 is a very good lens and its quotation are becoming ridiculous (almost like a Summarit 1.5), you shouldn't need to shim it to work on the Canon (the supposed incompatibility is overrated, all my soviet glass works on Leicas) but if it misses some screws the problem is a little more serious, I would recommend to post some pics on the FSU, there people can help you.
For the focus shift, that's typical of Sonnar designs: even the new Sonnar and the Canon 1.5 (which is a Sonnar design as well) are affected by it.
All things being equal, you're not really going to go wrong with any of those lenses. If the J-3 needs service (and you're not willing or able to do it yourself), then sending it off probably isn't a bad idea in any case. A few other things to remember about the Jupiter: it's a Sonnar, which means that focus shift is always going to be there, even if the lens is perfect - it's a function of the design - and the look of images from it are going to be different than the Planar-type Canon (I don't know what optical formula the Nokton uses, but I suspect it is closer to the Canon than the Jupiter). For me, the deciding consideration is the look of the photos - you have to decide what your priorities are, then decide what you need to get there.
I checked out on CV's website, the Nokton is a peculiar lens, given that they haven't changed it much in the transition from LTM to M mount here it's how it looks:

Definitely NOt a double Gauss.
This is the Canon 1.5:

This is of course the Jupiter 3:

The Canon 1.8:

In short if you want a Sonnar you either can repair the Jupiter 3, get a Canon 1.5 (shouldn't be too different from the Jupiter, probably better built) or if you are wealthy try to get a L39 Sonnetar.