M 28mm woes


fritzthedog

Link Posted 14/03/2011 - 19:29
I have 2 M 28mm lenses. One has a very small amount of fungus around the edge of the rear element - the other has a small scratch in the middle of the front element. Neither of these effect the performace - but I hate the fact that they are imperfect.

So - either remove the rear element and clean the fungus - or swop the front elements from one to the other - either would produce one perfect lens.

Problem - doing either of the above. I have dismantled and re-built many M 50s - I have all the right tools - lens spanners - friction wrenches etc.

I just can not get either the front or rear element to move on either of these. So either the design is substantially different to the M 50 and I am doing something wrong - or they are well and truly stuck.

Any ideas other than the obvious 'leave them alone if they are working fine'?

Carl
No matter how many lenses I have owned - I have always needed just one more

gartmore

Link Posted 15/03/2011 - 08:22
I had one M lens which needed repair and the only way the technician could remove the front ring was to drill two small holes in it for a wrench and then fill them with black resin.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

geordie01

Link Posted 15/03/2011 - 09:54
Try warming the outside of lens with a hair.dryer to make it expand slightly and then try to remove it

fritzthedog

Link Posted 15/03/2011 - 19:44
Thanks for the suggestions guys- will try the hair dryer first and if all else fails - the drill

Many thanks

Carl
No matter how many lenses I have owned - I have always needed just one more

Oggy

Link Posted 15/03/2011 - 21:05
Didn't some4one do a lens rebuild here not so long ago and used double sided sticky pads to stick the ring to a flat surface then unscrew the lens off it?

sorted78

Link Posted 16/03/2011 - 13:23
How about swapping the rear groups? I've taken my M28/2.8 apart to clean the diaphragm and it should be quite straightforward to change the rear group. From memory, I think you need to do something along the lines of the following:

- Remove the five screws from the flange on the mount.
- Lift mount off
- Use lens spanner to remove the rear group
- Replace rear group with non-fungus infected group from the donor lens
- Replace mount etc.

Best of luck
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