Jupiter 8 on Canon P

Hi,

I think it is a old discussion but I don't find and answer and a correct explanation. I had a Jupiter 8 lens LTM on Canon P body, from my tests it is work ok but on infinity focus the rangefinder patch is not correctly aligned, with my canon serenar 50mm f1.8 the patch it is ok, the same happened with a collapsible industar 50 mm f3.5 pictures are ok on close focusing and infinity but rangefinder patch not aligned correctly on infinity. There is some way to fix this? other than to calibrate rangefinder separately for every lens.

Thank you

Hi,

welcome to APUG !

On industar maximum f stop is 3.5 - so DOF will cover focus error. Jupiter has f2 - so critical focus is more important. I used Jupiter 8 for some time on Leica. You have two options: one is to stop the lens (lets say on f4-f5.6) when focusing close, and second is to measure distance with other tools and set distance manually looking at scale.

Calibrate rangefinder is not a cheap option, and not worth the trouble (imho).

Regards,
Darko

Thank you for the fast answer,

It is strange that with jupiter 8 the pictures look good even at f2 at close focusing and infinity focus, the only problem is the rangefinder patch that is not really snap on aligned on infinity like with serenar lenses, I don't really understand why.

No the rangefinder needs to be left at the LTM standard. It is not easy to adjust cause you need to do it for 1, & 10m as well as infinity, just setting it at infinity would be well silly it puts the other more critical distances out. It is a full Leica rfdr.

The lens is the problem.

It is possible to adjust the lens to be ok at infinity but it is better to set it to be accurate at 5 or 10 meters where you are going to use the rfdr at f/2.

Describe your J8 and provide serial nnnnnxx. You will need watch makers screw drivers and possibly shim stock and grinding paste... Doing the J8 is easier than the rfdr but still difficult.

Alternatively get another J8.

Alternatively ignore the problem.

edit the answer to your last question is the rfdr is ok for a 1.2 lens close in at 1.2 on a focus target, Id not worry with a f/2 and it may be ok close in anyway check that before much worrying. You need a proper focus target set up.

luck00 said:

It is strange that with jupiter 8 the pictures look good even at f2 at close focusing and infinity focus, the only problem is the rangefinder patch that is not really snap on aligned on infinity like with serenar lenses, I don't really understand why.

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If you search in google " fsu lenses + leica" you will find that Former Soviet Union lenses are not 100% compatible with Canon/Leica cameras.

For example one explanation is here:

http://www.pdexposures.com/soviet-rangefinder-lenses/

What you are describing is an annoyance, but not really a problem. If the camera/lens combo is focusing correctly in spite of the RF misalignment, and since you know what to look for in the VF, you can use the equipment effectively. No need to mess with anything.

That said, the lens may be shimmed to correct the discrepancy - this is well documented but tedious. Remember, you are dealing with two things: optical alignment and RF coupling. Right now, the more important optical alignment is seemingly correct; you would be trying to adjust the optical alignment to match the RF coupling of the lens (since the latter is fixed by the helical and the former is adjustable by minutely moving the optics within the barrel). The discrepancy may be due to the slightly different spec of Leica standard and Soviet lenses, or it may be dubious quality control or someone later reassembling the lens incorrectly; the cause is not particularly important.

Adjusting the RF is not advisable in this case, but in the event you need to, it is incredibly easy to do (seriously, I've adjusted Canon RFs in 15 minutes, working slowly).

Personally, I'd say leave it alone unless you are at least somewhat experienced with mechanical camera repair.

Thank you all for the answers. I think I will use my serenar 50mm f1.8 and in the future buying some 35mm canon lens.

luck00 said:

Thank you all for the answers. I think I will use my serenar 50mm f1.8 and in the future buying some 35mm canon lens.

Click to expand...

Good call - serenar is super lens. Eventually you can buy cheap Zorki or FED body - put Jupiter on it and you have spare body (or in one body B&W, in another color film).