On this particular ZK: I had to shim it the same way as I do most Jupiter-3 lenses for the Leica. I had to increase the shim. It was sent to me from Australia as the focus was off on the Leica. Got it all Cleaned/lubed/adjusted, made an offer for the lens which was accepted. I've seen ZK Sonnars with a lot of problems, including the focus index being at a 90degree angle from normal. Most required adjusting the shim, make it thicker.
The regular production LTM Zeiss Sonnars are usually accurate wide-open across the full focus range. I suspect this was done by moving the rear triplet in slightly closer to the front section.
The regular production LTM Zeiss Sonnars are usually accurate wide-open across the full focus range. I suspect this was done by moving the rear triplet in slightly closer to the front section.
TenEleven
Well-known
My 1948 ZK has perfect focus on the LTM standard and the lens was set to 51.6mm without me having to do anything. This was already apparent from the time I bought it as it was set in a Zeiss manufactured helical. (distance in 'm', stopper screw present).
However both the aperture and distance markings are 180 from normal when mounted in a Camera. I assume that this means the lens was intended for copy work or similar. (If the camera is in a copy stand the distance and aperture scales would face you) In the end it did not end up mattering because a previous "repairer" had butchered the focus mount to a point where I had to rehouse it in a J3. But again I didn't have to do anything else. Once infinity was set all the distances were spot on.
However both the aperture and distance markings are 180 from normal when mounted in a Camera. I assume that this means the lens was intended for copy work or similar. (If the camera is in a copy stand the distance and aperture scales would face you) In the end it did not end up mattering because a previous "repairer" had butchered the focus mount to a point where I had to rehouse it in a J3. But again I didn't have to do anything else. Once infinity was set all the distances were spot on.
TenEleven
Well-known
Also I guess one other thing I wanted to mention.
I have a Sonnar that looks almost normal except that the front element is un-coated and the middle triplet is weakly coated with a yellow-ish hue. The rear triplet looks uncoated-ish but is strangely transparent for being "uncoated". Unsure. 2.859xxx serial number (don't feel like digging it out right now) usual Zeiss stopper screw and nothing else abnormal really. Optics wise however it simply beats the pants off everything else I have. Amazing sharpness. The focus also stays dead put when stopping down.
I don't know what exactly they did to this particular one but I wish they did more of it!
Don't dismiss the irregular production lenses!
I have a Sonnar that looks almost normal except that the front element is un-coated and the middle triplet is weakly coated with a yellow-ish hue. The rear triplet looks uncoated-ish but is strangely transparent for being "uncoated". Unsure. 2.859xxx serial number (don't feel like digging it out right now) usual Zeiss stopper screw and nothing else abnormal really. Optics wise however it simply beats the pants off everything else I have. Amazing sharpness. The focus also stays dead put when stopping down.
I don't know what exactly they did to this particular one but I wish they did more of it!
Don't dismiss the irregular production lenses!
dexdog
Mentor
TenEleven, I have a 285 series lens in LTM that has a T coating. It does not look like anything special, but it is a very sharp lens, as good as any of my 272 series sonnars in LTM. I have sent the 285 lens to Skyllaney to be overhauled because while the glass is in great shape, the focus ring and aperture ring are just about immovable unless I inject a little lighter fluid to soften up the old grease. The lighter fluid works well for about a day, and then everything freezes up again.
I also have a regular production 285xxxx 5cm F1.5 Sonnar- picked up cheap many years ago. Took a lot of work. I hade to make a sleeve for the RF Cam to move in the mount to get rid of wobble due to wear on the helical. It was full of sand. After clean up and making the sleeve- very sharp, despite wear to the front coating. I had to use Vacuum pump grease for the helical. Maybe it was Afrika Corp.
bluesky4013
YH
I bought a 5cm Sonnar and at first I didn’t know what it is just noticed it looks nothing like normal Sonnars. Chris from Skyllaney contacts me and I send the lens to clean and let him do some search on it.
In the end, Chris found out some interesting things about this lens. First, it is actually a 58mm lens, and the construction is different from any 58mm Sonnar from the 40’s 50’s he has ever seen. The glasses are pre war Schott formular and some parts are similar to the nickel era Sonnars. Some internal characteristics are identical to some rare LTM version Sonnars.
I’ll quote the message from Chris for the internal mechanism:
‘ There is a secondary brass helicoid system that pre-translates the 58mm EFL of the optical block down to a 51.6mm movement, before then further sending this translation to the non sloped but rotating rear RF cam.
Honestly, I have not seen this method ever used before, but it is ingenious.
Instead of more modern fork sliders that appeard in the 1960’s, or set screws which were present in the 1940-1950’s LTM lenses…
This lens uses precision ground dowel pins, to stabilize and prevent optical block rotation when focusing.
These ground dowel pins are a mere 0.025mm undersized for the equally precise, reamed hole to which they travel inside.’
But it still left some mystery question to me, some parts are just not quite good as normal zeiss standard. Second, the aperture indication on the DOF uses old standard like early leica lens, which Zeiss never uses, and it doesn’t even match the scale on the front ring aperture.
In the end, Chris found out some interesting things about this lens. First, it is actually a 58mm lens, and the construction is different from any 58mm Sonnar from the 40’s 50’s he has ever seen. The glasses are pre war Schott formular and some parts are similar to the nickel era Sonnars. Some internal characteristics are identical to some rare LTM version Sonnars.
I’ll quote the message from Chris for the internal mechanism:
‘ There is a secondary brass helicoid system that pre-translates the 58mm EFL of the optical block down to a 51.6mm movement, before then further sending this translation to the non sloped but rotating rear RF cam.
Honestly, I have not seen this method ever used before, but it is ingenious.
Instead of more modern fork sliders that appeard in the 1960’s, or set screws which were present in the 1940-1950’s LTM lenses…
This lens uses precision ground dowel pins, to stabilize and prevent optical block rotation when focusing.
These ground dowel pins are a mere 0.025mm undersized for the equally precise, reamed hole to which they travel inside.’
But it still left some mystery question to me, some parts are just not quite good as normal zeiss standard. Second, the aperture indication on the DOF uses old standard like early leica lens, which Zeiss never uses, and it doesn’t even match the scale on the front ring aperture.
Thankyou for posting this! Chris Emailed me about this lens a while ago- a real mystery lens. I also note that this F1.5 lens used a rear Doublet rather than the Triplet of most F1.5 Sonnars. There were some odd ones made, and I've seen a block diagram of a 1-3-2 5cm F1.5 Sonnar, and from the best I can tell- picked up one at random. The rear fixture is different from my Triplets. Lens is in poor condition, was heavily used. It is a Contax mount lens.
dexdog
Mentor
bluesky, thanks for posting, you have a very interesting lens. Sounds like Skyllaney is a pretty good forsenic pathologist for lenses.