Matthias Wilke wrote:
> The screens are fragile because of the used material - plastic.
I suspect they're not the same optical resin that is used in moulded
spectacle lenses. Those can be cleaned with a special, pure solution
of isopropyl alcohol obtainable from good opticians. Believing camera
lens cleaner was similar stuff, I tried to use that to get goo off
the screen in my OM-1. It softened the surface, and, even with gentle
handling, lens paper produced scratches. I haven't tried the spectacle
lens cleaner with a focussing screen. Maybe it's better quality than
camera lens cleaner, or, more likely, the OM screens are different
plastic.
Optical resin spectacle lenses should be replaced every 12-18 months
because of microscratches on the surface, so I don't expect to be
able to handle focussing screens much. Choose one and leave it
in the body (e.g. 1-4 for a fast-film body used with mirror lenses).
> When cleaning a screen, I would only use air,
> destilled water or a clean natural hair cosmetic brush to touch the screen,
> not the ugly brush, which comes with the screen. With this brush it is
> possible to produce scratches you can see through the viewfinder.
Like some other posters, I have successfully cleaned a focussing
screen using (biodegradeable) dishwashing liquid. I used three drops
in a coffee mug of lukewarm tap water, followed by three cold rinses
and drying in still air. I used the supplied tweezers to hold the
screen. This procedure removed dust and fingerprints from a "new
unused in box" screen I bought.
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|