Minolta MD 200/4 Tele Rokkor: Rubber coating on the focus ring adjusted, optics cleaned

This MD 200/4 comes from a collection of defective lenses.


The

Rubber coating on the focus ring

was overstretched and no longer closed flush with its lead. Presumably the effect of heavy use, as signs of wear can also be seen on the outside of the tube.






Unfortunately I neglected to take photos; here you can see the problem on an MD 50/1.7

In itself, this is only a cosmetic matter, as the function of the focus ring is not restricted. But it doesn't look good and I find the loose rubber coating unpleasant to the touch.

So I looked at what I could do here.




I pulled off the rubber coating and cut it with the knife.

I then measured with my eyes and cut off a strip lengthwise.






The „fitting“ showed that the width was now correct.

The rubber coating was just too long.




Another cut corrected the length.

Now it was fine.








Before I finally attached the rubber coating, I cleaned it with Sonax All-Purpose Cleaner Foam.

Dirt from the decades went off.




After rinsing with water, I dried the strip with the Dremel Versatip butane gas burner.

The moisture also evaporated from the recesses.




I removed any remaining dirt with isopropyl alcohol.






I attached the rubber coating with Pliobond Special Purpose Adhesive. A removable adhesive for leatherettes on cameras.

I applied the glue to the rubber coating and tube for a better hold.




Press firmly - sits.




It was a little too long here ...

I find Pliobond is removable if I only put it on one surface and then assemble while the glue is still a teensy bit wet. If I put it on both surfaces, wait for it to almost dry, and then place the parts together with some pressure then the bond isn't very easy to undo.

YMMV and all that. Oh, heck - YMWV.

… corrected




Remains of Pliobond …




… could be removed easily and without leaving any residue.








I hadn't exactly separated here, filled the gap from the scraps and removed the Pliobond residue with isopropyl alcohol.


On to the optics



In order to be able to remove dust on the front lenses, I dismantle them from the front.






The engravings ring could not be loosened with the spanner wrench; it was bolt tight.

Applied WD-40 and waited a few minutes - now it worked.






The engravings ring closes with a plastic ring, which in turn sits on the front lens.








Removing the front lenses with the lens sucker.




This is the end of the line, I couldn't remove any lint from under this lens. To do this I would have had to disassemble the lens further, which I wanted to avoid.

Before assembly, I removed the applied WD-40 from the individual parts with isopropyl alcohol.

As useful as its properties as a penetrating oil are when it comes to loosening stuck rings, further migration to the optical elements would be unpleasant.




I cleaned the front lens with the Zeiss lens cleaning set.


Cleaning rear lens and aperture ring

One of the rear lenses on this telephoto was also very dirty.

And the aperture ring needed to be de-oiled and re-greased.

I have not documented the cleaning of the lens and aperture ring here, it corresponds to the type of contamination and process as I reported in this article:



Final



Exterior cleaning with Sonax Foam.

I don't use the cloth that can be seen in this picture to clean the optics




Back to work.






The now adapted rubber coating.




Another piece saved from the bin


+++

All information provided without guarantee and use at your own risk.

Nicholas Lindan said:

I find Pliobond is removable if I only put it on one surface and then assemble while the glue is still a teensy bit wet. If I put it on both surfaces, wait for it to almost dry, and then place the parts together with some pressure then the bond isn't very easy to undo.

YMMV and all that. Oh, heck - YMWV.

Click to expand...

Exactly, the rubber coating shouldn't be removed anymore, so I applied Pliobond to both sides.

Andreas Thaler said:

Exactly, the rubber coating shouldn't be removed anymore, so I applied Pliobond to both sides.

Click to expand...

Ah, Nikon is fond of hiding itty-bitty screws under the rubber...

Nicholas Lindan said:

Ah, Nikon is fond of hiding itty-bitty screws under the rubber...

Click to expand...

I sometimes think that the designers did this on purpose so that at least when you disassemble the lenses you think about them and their work …