hamradio
Well-known
So, I picked up a J9 on a whim in LTM. Beautiful shape, chrome, made in '56. I threw it on my Bessa R, fully not expecting it to focus properly. Put the shutter in B with a cable release, opened the back, placed an old SLR focusing screen in the film gate.
Lo-and-behold, it works almost perfectly. Infinity is dead on, 2m is dead on. At its closest, 1.15m and f/2, it's just a hair off--maybe an inch or two. Its barely a difference, and in practice, I think user error with the RF would make more of a difference...it's one thing to focus at a black cross on paper as a target, but when I focus at random things around the house, my own focusing has a little error. Any discrepancy is gone by f/4.
I put the lens on my known-good Fed 2, and it seems as if the error might be greater.
This brings up the question:
This makes me wonder,
Is the close-focusing error due to the lens itself being spec'd to a different RF standard, or is it due to the focus-shift with Sonnars? For those who've tried J9s on normal LTM bodies, how far off was the focus? It's not like I can really adjust anything with this lens...there's one shim for the whole optical unit to adjust infinity focus, and no shims for the rear cell. I'd have to manually lap down the metal on the cell.
Lo-and-behold, it works almost perfectly. Infinity is dead on, 2m is dead on. At its closest, 1.15m and f/2, it's just a hair off--maybe an inch or two. Its barely a difference, and in practice, I think user error with the RF would make more of a difference...it's one thing to focus at a black cross on paper as a target, but when I focus at random things around the house, my own focusing has a little error. Any discrepancy is gone by f/4.
I put the lens on my known-good Fed 2, and it seems as if the error might be greater.
This brings up the question:
This makes me wonder,
Is the close-focusing error due to the lens itself being spec'd to a different RF standard, or is it due to the focus-shift with Sonnars? For those who've tried J9s on normal LTM bodies, how far off was the focus? It's not like I can really adjust anything with this lens...there's one shim for the whole optical unit to adjust infinity focus, and no shims for the rear cell. I'd have to manually lap down the metal on the cell.
Dez
Bodger Extraordinaire
It's more likely that the lens wasn't shimmed properly when it was made, and you got lucky that it close focused correctly on your Bessa.There was a lot of variation in these lenses. Even a broken clock is bang on twice a day.
Cheers,
Dez
Cheers,
Dez
Robert Lai
Well-known
I had one of these in LTM mount built to the Contax register. It was fine at infinity, but at minimum focus it was about 1 foot off. If you're within an inch or so, then you truly are lucky.
dee
Well-known
I have a Fed 50mm f3.5 collapsible which focuses perfectly on the M8.
Other Industars etc do not.
I guess I just got lucky with poor construction.
Other Industars etc do not.
I guess I just got lucky with poor construction.
rjbuzzclick
Well-known
On FED's and Zorki's with an RF cam that's wedge shaped, pivoting the cam adjusts close focus. Here's a page that describes it:
http://jay.fedka.com/index_files/Page422.htm
Lenses should always be set to the closest focus distance setting when mounting, otherwise it can knock the cam out of alignment.
My Jupiter 9 (later black one) was fine at infinity but out at close distances. Adjusting the cam fixed it. As it turned out (obviously), this also corrected close focus errors on my other FSU lenses, which I hadn't noticed before because they are all shorter focal lengths and the error wasn't nearly as bad.
On a camera without an adjustable cam, you can adjust the shim of the rear lens group only to try and correct close focusing errors. Again, mine is a black one and I'm not sure if the silver ones have this shim or not. This will slightly lengthen or shorten the focal length of the lens. This can throw infinity out of whack however, which would then need to be dealt with by adjusting the shim for the whole optical block, which could then throw close focus out again. It could become a vicious circle...
http://jay.fedka.com/index_files/Page422.htm
Lenses should always be set to the closest focus distance setting when mounting, otherwise it can knock the cam out of alignment.
My Jupiter 9 (later black one) was fine at infinity but out at close distances. Adjusting the cam fixed it. As it turned out (obviously), this also corrected close focus errors on my other FSU lenses, which I hadn't noticed before because they are all shorter focal lengths and the error wasn't nearly as bad.
On a camera without an adjustable cam, you can adjust the shim of the rear lens group only to try and correct close focusing errors. Again, mine is a black one and I'm not sure if the silver ones have this shim or not. This will slightly lengthen or shorten the focal length of the lens. This can throw infinity out of whack however, which would then need to be dealt with by adjusting the shim for the whole optical block, which could then throw close focus out again. It could become a vicious circle...
johannielscom
Snorting silver salts
Back in the day when I found one, I made a small study of the Jupiter-9 type I purchased.
The mythical perfect-focusing Jupiter-9 is in fact a late 1940s Carl Zeiss Sonnar 2.0/85mm in a barrel that is marked Jupiter-9.
Main difference is that the original Zeiss Sonnar focuses down to 1.8 mtrs and to get it to register correctly on a Russian body, is actually set to 83.4mms focal length, by threading it into the barrel slightly too far. As a result the infinity marks on barrel and optical block are offset, approx 1/3 inch. This allows it to reach infinity on a Russian rangefinder, while on a Leica it's actually spot-on in the close range and maybe ever so slightly off at infinity but DOF covers that.
The Russians used the remaining Carl Zeiss optical blocks first, then they redesigned the whole Jupiter-9 to focus correctly on their Contax focusing-based rangefinders. It was redesigned to focus correctly through the whole distance range and that also allowed it to focus close at 1.15mtrs.
I sold my 1950 Carl Zeiss based Jupiter-9 to Dirk but if I hadn't done that, I might still be shooting Leica today. It was that good...
The mythical perfect-focusing Jupiter-9 is in fact a late 1940s Carl Zeiss Sonnar 2.0/85mm in a barrel that is marked Jupiter-9.
Main difference is that the original Zeiss Sonnar focuses down to 1.8 mtrs and to get it to register correctly on a Russian body, is actually set to 83.4mms focal length, by threading it into the barrel slightly too far. As a result the infinity marks on barrel and optical block are offset, approx 1/3 inch. This allows it to reach infinity on a Russian rangefinder, while on a Leica it's actually spot-on in the close range and maybe ever so slightly off at infinity but DOF covers that.
The Russians used the remaining Carl Zeiss optical blocks first, then they redesigned the whole Jupiter-9 to focus correctly on their Contax focusing-based rangefinders. It was redesigned to focus correctly through the whole distance range and that also allowed it to focus close at 1.15mtrs.
I sold my 1950 Carl Zeiss based Jupiter-9 to Dirk but if I hadn't done that, I might still be shooting Leica today. It was that good...
ferider
Veteran
I tried 3 J9 lenses - if I remember correctly - and they all front-focused by about 6 inches or so.
Finally I did get a 1950 85/2 ZK with 1.8m min focus that focused correctly (see also Johan's comment). But I found the 1.8m min focus too limiting and kept using my Nikkor Sonnars instead.
From using the 8.5/10.5cm Nikkors (now also on digital), I know that an inch or two front focus is OK, since the Sonnars shift backwards when closing down, so a slightly front focusing lens at f2 will be perfect at f2.8. If you only use M cameras with the lens, you have the option to otpimize an LTM tele for a specific f-stop by grinding the RF cam and/or the adapter, if you are up to it.
Note that the 8.5cm Nikkor is a bit harder than the original Sonnar/Jupiter, sharper but overcorrected. On the other hand, the 10.5cm Nikkor has the smoothest bokeh you can find in a tele lens, since it's intentionally undercorrected close up and wide open at the cost of lower resolution at infinity until stopped down to f5.6 or more.
Knowing this, and since I have the two Nikkors, I never felt the need to try a J9 again.
Roland.
Finally I did get a 1950 85/2 ZK with 1.8m min focus that focused correctly (see also Johan's comment). But I found the 1.8m min focus too limiting and kept using my Nikkor Sonnars instead.
From using the 8.5/10.5cm Nikkors (now also on digital), I know that an inch or two front focus is OK, since the Sonnars shift backwards when closing down, so a slightly front focusing lens at f2 will be perfect at f2.8. If you only use M cameras with the lens, you have the option to otpimize an LTM tele for a specific f-stop by grinding the RF cam and/or the adapter, if you are up to it.
Note that the 8.5cm Nikkor is a bit harder than the original Sonnar/Jupiter, sharper but overcorrected. On the other hand, the 10.5cm Nikkor has the smoothest bokeh you can find in a tele lens, since it's intentionally undercorrected close up and wide open at the cost of lower resolution at infinity until stopped down to f5.6 or more.
Knowing this, and since I have the two Nikkors, I never felt the need to try a J9 again.
Roland.
Brian Legge
Veteran
I understand the alignment issues with M39 ones... but does anyone have any experience with the focus success using a Kiev/Contax mount J9 on a Amedeo M39 adapter?