Quote Originally Posted by Woolliscroft
I have a house full of OMs and have never seen this problem. My 1 and 2s are all the n models, so maybe they aren't affected.

I think it's one of those things that is just a matter of time. They can last longer in some climates, etc., but if the foam is in there it WILL eventually deteriorate and take the silver off the prism. I have 4 OM's and none of them have had this happen, but I don't want to take the chance. I have a friend that has an OM-1 this has happened to - it doesn't affect the image on film, just drives you crazy when you look through the viewfinder.