Comparing CZJ 272 Sonnars

dexdog

dexdog

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I have gathered together all of the 272 series CZJ f1.5 Sonnars I have for a comparison (yeah, it is good to be retired). Family portrait of sorts, three LTM Sonnars, four 1950 and 1951 Jupiter 3s in LTM. These are arranged by CZJ serial number, from lowest to highest. CZJ serial numbers are 2724915, 2724921, 2725606, 2726544, 2727059, 2727213 and 2727386. You should be able to access higher resolution by clicking on the pic and typing RFF as the password.
 
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I photographed my bookcase again at a measured one meter wide open. With one exception, the pics are all very pretty good. The exception is the lens with lowest serial number, 2724915. Something is wrong with this one. The nearby serial number of 2724521 looks pretty good.
Lens 2724915 wide open. Appear to be a LOT of field curvature on the first lens.

Lens 2724921 wide open

I know from my notes that when Brian looked at this lens years ago that the focus cam of this lens is 2mm too long, i.e., it sticks out the back of the mount at close focus, but since I am using a mirrorless Sony is not an issue. Brian also said that the lens had an experimental aluminum barrel.
 
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Even a lens with horrendous damage to the front element, CZJ 2727213 (Jupiter 3 5103453) does OK, but has lost sharpness and contrast as one might expect, and would be very prone to flare if used in sunny conditions
Lens 2727213 wide open

damaged front element. Those are not fingerprints, lens is clean, just very beat up.
 
Took lenses 2724915 and 2724921 outside to check for de-centering, I don't think either lens has a decentering issue. Distance is 5 meters at f4. Yeah, the horizontal boards flow downhill to the left a bit, so that is not the lens. I used the bubble level on tripod, so camera is square with the world. The second lens is better (more field curvature in first lens?), both were focused at 5.9x on the Sony, so it was not an issue of me messing up the focusing.
2724915 5 meters

2724921 5 meters
 
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Looking at all of these lenses together, while my BLL Jupiter 3 serial 5001032 / CZJ serial 2727386 is the best one, it is not that much better than the rest of them. So while the 272 series lenses may be among the best sonnars ever, a lemon occasionally escapes quality control. Of course, there is no telling what happened to 2724915 in the 80+ years since it was made. I wish I knew. Given how bad 2724915 performs, makes me wonder if the front element is ground incorrectly. I could swap in a different front element, pretty sure that I have an acceptable front element from a 1951 J-3 in the parts bin, but will not do so today. Yard work beckons.
 
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I'm thinking we should transplant the glass of the first 272 into a different barrel. I have to think the position of the optics is incorrect.
 
dexdog said:
I have gathered together all of the 272 series CZJ f1.5 Sonnars I have for a comparison (yeah, it is good to be retired). Family portrait of sorts, three LTM Sonnars, four 1950 and 1951 Jupiter 3s in LTM. These are arranged by CZJ serial number, from lowest to highest. CZJ serial numbers are 2724915, 2724921, 2725606, 2726544, 2727059, 2727213 and 2727386. You should be able to access higher resolution by clicking on the pic and typing RFF as the password.
Click to expand...
Mate, you need to send one of those to NE England with some cash your way ;) 🤣
 
Sonnar Brian said:
I'm thinking we should transplant the glass of the first 272 into a different barrel. I have to think the position of the optics is incorrect.
Click to expand...
Would a 1951 J-3 optical block and barrel work? I have a couple that current have decent glass in them, but resurrecting a 272 might be worth it. I also have a 1957 or 58 J-3 as a possible donor.
 
dexdog said:
Would a 1951 J-3 optical block and barrel work? I have a couple that current have decent glass in them, but resurrecting a 272 might be worth it. I also have a 1957 or 58 J-3 as a possible donor.
Click to expand...
Absolutely. I’m a nut for them. Plus working on lenses is therapy to me. I just “get it” unlike when I went into cameras and had to mess around with the Zorki slow speed govenor to which led to a tantrum and me launching the shutter crate up the garden 😳🤣 - These 272 lenses definitely seem to be near perfect for me.
 
dexdog said:
Would a 1951 J-3 optical block and barrel work? I have a couple that current have decent glass in them, but resurrecting a 272 might be worth it. I also have a 1957 or 58 J-3 as a possible donor.
Click to expand...
Yes- I have used those before with CZJ Sonnar 5cm F1.5 optics.
 
I put the lens groups from Sonnar 2724915 as seen in post #2 above into a CZJ 166 series optical block. The optical fixture is alloy for the 272 and brass for the 166. The 166 fixture was also of a slightly different design. Series 272 optical fixture on left, series 166 on right.

Swapping the lens groups between the two was pretty easy, rear triplet from the 272 screwed into donor fixture no problem, front elements were same size at 35.98mm, middle group was 31.22 on the 272 series and 31.20 on the 166 series. I took me two tries to get the middle element from 272 centered in the 166 optical block, but it worked OK. The retaining rings for the two middle groups were not the same size, so I used the ring from the 166 series. I shimmed the optical block so that it passed the one meter wide-open test. I think it worked, a comparison of before and after is significant. Yeah, I shoulda taken a pic with the original 272 configuration in order to get the exact setup and lighting conditions,but forgot.

Original 272 series, one meter f1.5

New Franken-lens 272, one meter f1.5


Higher resolution images may be seen by clicking the pic and using RFF as password
 
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For comparison, the BLL Sonnar 2727386, one meter f1.5


Franken-lens one meter f1.5


I still need to index the Franken-lens, need to roll the aperture scale starboard about 9mm. A combination of 2 shims totalling 0.94mm were just about prefect for the "new" lens.
 
That's really good! I'm guessing the spacing between groups is way off on the original Barrel.

You now have the Heaviest "272" series Sonnar ever produced.
 
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