M39 adapter, Leitz, and Jupiter-8

[reakeener1970]

Hi,

I have a Bessa R3A with M-mount but have M39 LTM adapter pretty much permanently bayonetted in as all my lenses are older threaded ones. Something I have noticed, though, is that when the Leitz lenses (90mm Elmar and 50mm collapsing summitar) are screwed in, the focus notch (that aligns with the distance scale on the lens to indicated what distance it is focused at) on the lens is a little off the 12 o'clock position (say 12:15 or so, 2 or 3 millimeters off) if you were looking at the front of the camera. Conversely, the Jupiter-8 (all black one) lines up right on the mark.

Now, I know about the whole Jupiter-8 Russian factory shim issue to get correct focus on non-russian cameras, so I would think the opposite would be true, but it isn't.

I have not run extensive sharpness tests or anything like that yet because, frankly, it is not something I think about much when I would have time to do it. Just curious if anyone has noticed the same thing with their lenses and M39 to M adapters.

I have not run any front/back focus tests yet but figured I would not re-invent the wheel if someone else already has. I certainly have not noticed any gross focussing errors with any of them but my subject is also usually a moving toddler!

Thanks!

 

[reakeener1970]

You know what. Did some searching and found some info so I am good. That said, if you want to chime in, still feel free!

 

[Mustafa Umut Sarac]

reakeener1970,

If you want to share what you have found , feel free. This forum is not for fast chat but google searchers. Thats the way , things work.

 

[Ko.Fe.]

...
Now, I know about the whole Jupiter-8 Russian factory shim issue to get correct focus on non-russian cameras, so I would think the opposite would be true, but it isn't.
....

Jupiter-8 were shimmed for FSU cameras as well.


Only two frames needs to be taken with test target to know if focus is correct. One with RF, one with scale.

 

[gone]

I've owned a lot of J-8 lenses, and they all focused perfectly w/ no shimming on my Leica screwmount, Bessa R, and R2A cameras, even wide open at close focus distance. Nice little lenses, but I much prefer a Summar for it's IQ.

 

[Sewin]

My black Jupiter 8 is slightly off centre on my Zorki, doesn't seem to make any difference to the images.

 

[Dr Croubie]

Ran a few tests on my bodies, only got the one adapter, a Voigtlander 35/135:
On my R4A (and presumably the same on my R3A because it's the same adapter):
Industar 61 2.8/53, about 12:15
Jupiter 8 50/2, about 12:30
Apo-Lanthar 90/3.5, 12:15
Skopar 21/4, 11:55

On my Bessa L:
Industar, 12:15
Jupiter, 12:15
Apo-Lanthar, 12:02
21/4, 11:30

Never noticed any major issues.
I have been shooting the Jupiter a lot wide-open lately, but when it's on Delta 3200 I doubt I could see any focus issues inamongst the grain.