Summicron DR Lens Head Detachment Problem

[Daniel Schutte]

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Hi everyone,

I own a Summicron 50mm V2 DR and Type 1.

I know the lens head should be detachable from the focusing mechanism in order to mount on bellows. This works correctly on the Type 1, but on the DR, when I turn the lens head, only the section housing the front elements rotates, thus revealing the aperture blades inside once removed, instead of detaching all elements in one block. I could try bypassing this section by rotating the aperture ring, but this feels unsafe as rotating the ring with force might damage the blades inside.

I hope I've explained this clearly enough - not sure if anyone has a solution? I'm trying to remove the lens head on both lenses in order to swap them out, since the DR optics are cleaner but I prefer the size of the Type 1.

(P.S. I'm not the type to attempt lens repair/cleaning myself, but this is a function built into the lens by Leica)

Thanks in advance

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[TomB_tx]

My DR has the same issue. It was also a bit hazy so I sent it to DAG for a CLA. It came back perfectly clear, but the entire optical head still won't unscrew. I assume the head-to-mount thread was overtightened enough that it's going to stay mated, and if DAG didn't figure out a way to separate them, I'm going to leave it as is. I have a normal rigid also if I ever need to use a lens head alone.

Swapping lens heads may not work well, as the focusing mount is matched to the exact focal length of the optics. I recall that the DR lens heads are all chosen for nominal FL, but not the normal rigid, which has at least 3 different mounts for FL variations. 

[a.noctilux]

Swapping lens head is not so good idea.

Having many DR lenses and knowing they are all 51.9mm lenses, I wanted just for fun swapping the optical cells.

Between two of them, I was not able to screw-in to show the aperture index at precisely "noon".

I gave up and I have to admit that each lens was adjusted with the lens mount/ optical cell with same serial number.