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As for lubing the 50/1.5 focusing mount, if anyone else is brave, I'll explain.
The outer slotted ring on the rear holds the lens barrel into the focusing mount. Remove with spanner wrench. It is tight. Don't lose the spacer ring.
To split the focusing mount, start by removing the slotted brass ring from the front with a spanner. It holds in the non-rotating stepped brass collar that the lens block mounts into. Pull out the brass collar.
Now, focus to infinity. Remove the three screws on the back of the lens. Using tweezers, slide out the stop that it holds. Now you should be able to split the focusing helix. As always, note VERY CAREFULLY the relative rotational positions of the two halves of the helix when they come apart.
If you need to take off the parts of the focusing collar, there's one curve ball. There are three obvious screws that hold on the front dress ring. There is a fourth, it's one of the ones holding in the black tabs, it's 90 degrees from two of the other screws.
There is a second set of 4 screws that hold the focusing ring to the back of the helical. You may have to pull them to get good access to the helical for cleaning.
You will also want to clean and lube the inside of the stepped brass collar.
I can't say what the ideal lube is. LaBelle Teflon grease was too stiff. Lubribplate lithium soap grease is what I have in there now, too slick.
When you are done putting it back together, the focusing cam should stick out 7.5mm from the mounting plane when focused at infinity. If not, you're on the wrong start of the helical threads. (Try again.)
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The outer slotted ring on the rear holds the lens barrel into the focusing mount. Remove with spanner wrench. It is tight. Don't lose the spacer ring.
To split the focusing mount, start by removing the slotted brass ring from the front with a spanner. It holds in the non-rotating stepped brass collar that the lens block mounts into. Pull out the brass collar.
Now, focus to infinity. Remove the three screws on the back of the lens. Using tweezers, slide out the stop that it holds. Now you should be able to split the focusing helix. As always, note VERY CAREFULLY the relative rotational positions of the two halves of the helix when they come apart.
If you need to take off the parts of the focusing collar, there's one curve ball. There are three obvious screws that hold on the front dress ring. There is a fourth, it's one of the ones holding in the black tabs, it's 90 degrees from two of the other screws.
There is a second set of 4 screws that hold the focusing ring to the back of the helical. You may have to pull them to get good access to the helical for cleaning.
You will also want to clean and lube the inside of the stepped brass collar.
I can't say what the ideal lube is. LaBelle Teflon grease was too stiff. Lubribplate lithium soap grease is what I have in there now, too slick.
When you are done putting it back together, the focusing cam should stick out 7.5mm from the mounting plane when focused at infinity. If not, you're on the wrong start of the helical threads. (Try again.)
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