A pristine 1960 Jupiter 3 with focusing problem.

dexdog

dexdog

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I bought a lens recently from a US eBay seller (yeah, I have a problem...). Seller said that the lens was like new, which in eBay terms often means well-used. I was shocked to see that the lens in fact looks brand new. The glass is perfect, not even a fingerprint




The lettering on the lens is crisp, has not been polished- you even even see tiny burrs from the spinning engraving tool with a 20x magnifier. There is not even any black crud in the lens mount itself. I put the lens on my Sony a7III for the one-meter wide-open test, it front focused about 20mm, which suggests that the shim is too thick. Took the thing outside for pics at known distances from my front porch, infinity focus was about 75 meters. Images at 75 meters wide open were not at all sharp in the center. I could get a so-so image by stopping down to f2.8, and a decent image at f4. In addition, distances farther away that 75 meters were very out of focus.
 
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I was scratching my head about what to do, swapped in a total of 3 LTM to E-mount adapters, same story. I somehow remembered a Sonnar Brian comment about trying to adjust the spacing on the lens groups, so I figured I would give it a try. The optical block was very hard to unscrew from the focusing mount, had to use surgical tubing to spin it out. Some old grease inside of course, but looking at it made me wonder if the lens had ever been taken apart. I unscrewed the rear lens group about half a turn using surgical tubing (very, very tight), put the thing back together and gave it a try. Lo and behold, I now have infinity focus at about 300 meters, even at f1.5. Close focus on the one-meter wide-open test improved too, only front focuses by about 3mm. So, I have tinkered with it enough for today, but wanted to ask folks on the site why unscrewing the rear lens group worked. Ideas? Depending on any responses, I might tweak the rear group one way or the other in the coming days just for fun.
 
Lastly, I wonder if this lens is in such great cosmetic condition because a few people tried it out, figured it was a crappy lens and set it aside.
 
Yes, if pristine, it is often due to the problem.
I'm not strong in theoretics, I have rear lens unscrewed to get focusing working.
And I would not worry about 3mm .
 
Ko.Fe. said:
Yes, if pristine, it is often due to the problem.
I'm not strong in theoretics, I have rear lens unscrewed to get focusing working.
And I would not worry about 3mm .
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When I was using Kiev cameras I always stayed away from the pretty ones - they never worked. People bought them, they were borked and then got thrown in a drawer for 30 years. Same with lenses, though with Kiev mount there was less to go wrong.

I keep looking for a scruffy mid 50's Kiev 2 with a J3 for the right price 😉
 
Unscrewing the rear group acts "almost" the same as reducing the main shim, the distance from the back of the lens is closer to the image plane.
It's preferable to reduce the thickness of the main shim. Moving the rear group out does slightly increase the overall focal length of the lens. A 20mm front focus at 1m means the shim is ~0.1mm too thick. Easiest Fix- reduce the shim so the lens screws in 1/3rd of a turn deeper than the original position. Then undo the 3 set screws, re-index- and screw back in. The Taps should align well enough for the screws to go back without too much fuss.

My Best Jupiter-3 is from 1950, was never used. The focal length was too short even for a Leica, and I had to increase the distance between the rear group and front section.
 
Sonnar Brian said:
Unscrewing the rear group acts "almost" the same as reducing the main shim, the distance from the back of the lens is closer to the image plane.
It's preferable to reduce the thickness of the main shim. Moving the rear group out does slightly increase the overall focal length of the lens. A 20mm front focus at 1m means the shim is ~0.1mm too thick. Easiest Fix- reduce the shim so the lens screws in 1/3rd of a turn deeper than the original position. Then undo the 3 set screws, re-index- and screw back in. The Taps should align well enough for the screws to go back without too much fuss.

My Best Jupiter-3 is from 1950, was never used. The focal length was too short even for a Leica, and I had to increase the distance between the rear group and front section.
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Thanks, may have to go through my small collection of shims to see what I can come up with. The existing shim is 1.20mm. It would be refreshing to be able to reduce the shim a bit and use the same tap holes, that hardly ever happens.
 
wlewisiii said:
When I was using Kiev cameras I always stayed away from the pretty ones - they never worked. People bought them, they were borked and then got thrown in a drawer for 30 years. Same with lenses, though with Kiev mount there was less to go wrong.

I keep looking for a scruffy mid 50's Kiev 2 with a J3 for the right price 😉
Click to expand...
Yes, had Moskva-5 like new, it was with faulty RF prism. And buying like new Zorkis was straight to complete CLA, with de-gunking of rollers springs.
 
dexdog said:
Thanks, may have to go through my small collection of shims to see what I can come up with. The existing shim is 1.20mm. It would be refreshing to be able to reduce the shim a bit and use the same tap holes, that hardly ever happens.
Click to expand...
I always used paper and sharp scissors for nails.
But if it is three mm on one meter it is within error margin, and three hundred meters on WO ... it is like from factory 🙂
 
I found a shim for the J-3 that is 1.02mm thick that worked well, it passed the one meter test. The aperture ring needs to be rotated about 90 degrees starboard to index properly, will probably do that later today. Attached pic is midway through the shimming process, this shim augmented with orange masking tape was a bit too thick. Just a pic to show how pretty this lens is inside, which lead me to conclude that no one had been inside before. Time for a dog walk.
 
Check focus at infinity- just to verify the position is good. If it's good from 1m to infinity, shim is perfect and focal length is close to Leica.
 
Infinity focus shifted outward a bit, probably about 350 meters as judged by Google Earth. I am happy to get the lens shimmed properly, and even happier that it is in outstanding condition. I have purchased a lot of lenses from eBay since 2005 or so, only one or two were so pretty.
 
@dexdog Yeah- I get that. I have a perfect 1975 J-3 that is very sharp, one of the best I've seen. It was WAY off when received, and the grease had solidified. Now- perfect focus, and smooth as can be. Great optics, "Misassembled" at the factory. Nobody fixed it until 40+ years later.
 
Nobody fixed this one for 65 years. Thanks for the help. Skyllaney fixed my 1950 J-3 with CZJ 272 serial number in 2023, which puts it at 73 years. That 1950 J-3 may be my best, and is certainly my favorite.🙂
 
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Low evening sunlight infiltrating the blinds in my bedroom, lighting my armoire. Pic is about 2.5 meters, wide open. I like this one because it highlights the funky figure of the cherry doors, also like the shadow of the left door knob. Straight outta camera jpeg from Sony a7III
 
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I also like this image because it illustrates the amazing improvement in the dynamic range of digital sensors in the last 10 years or so. Yeah, the highlights are blown out on the bright sunny areas, but would it be that much different on film without dodging and burning the print? The camera I used for this image was released in 2018. I have been tempted to upgrade to a current model Sony, but have a hard time justifying whether I would be any happier with the rendering of the image. The "obsolete" Nikon Z6 that I have also falls into the same category. I love these cameras and the images that they produce.
 
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