ben_ford2 Posted July 14, 2007 Share Posted July 14, 2007 I have what appears to be some bizarre growth inside the prism of my OM-1; it's this weird green stuff just at the bottom of the viewfinder. There's a long strip of it on either side of the V, and flecks coming off of it. They all seem to be surrounded by some kind of weird jelly-like substance. I will try and attach a pic (I'm not sure how) but it's very hard to take a photo of. It almost looks like the furry material on the inside has become wet and flaked off..But I don't see how this could have happened. Could it be fungus? The camera was left by a clueless relative on a sunny windowsill in a full leather case for several days, so I'm thinking it may be fungal growth due to the moisture inside the case (leather 'sweats', does it not?). Thankfully, the lens does not appear to have any of this stuff on it and looks crystal clear. I'm not really sure what to do. Should I detach the lens from the body and store it seperately in case it is fungus? I do not want to lose this camera/lens as it has great sentimental value. Thanks Ben (picture attached:) <img src="http://s83.photobucket.com/albums/j311/piscator_robotico/?action=view¤t=stuff.png"> Link to comment Share on other sites More sharing options...
richard_oleson Posted July 14, 2007 Share Posted July 14, 2007 I can't make anything out of the photo, but it could be fungus; also, in the OM-1 in many cases the foam on top of the prism deteriorates over time and attacks the silvering. In either case, I don't think this is likely to be the result of "several days", it has probably been slowly developing for some time. The prism will continue to get worse unless the source of the problem is cleaned out, and if it has great sentimental value (ie, you might want to keep it for a future generation), you might want to pay to have the prism replaced. Link to comment Share on other sites More sharing options...
warren_au Posted July 14, 2007 Share Posted July 14, 2007 It doesn't look like fungus. I'd guess it is disintegrating or melting foam. Link to comment Share on other sites More sharing options...
ben_ford2 Posted July 14, 2007 Author Share Posted July 14, 2007 I've attached a better picture below. I think the prism will probably have to be replaced. It may not have happened over several days, but I think the several days spent in the sunlight definitely did it no good. I didn't notice this beforehand. What would you estimate as the price of a new prism inc. work? Link to comment Share on other sites More sharing options...
john_hermanson2 Posted July 14, 2007 Share Posted July 14, 2007 OM-1 (and OM-2) were made with pieces of foam rubber pressing against the prism, under the top cover. With age (oldest OM-1s are 33 years old now) the foam turns to tar and eats through the pentaprism coating, leaving large black or green blobs in the viewfinder. Best fix is to replace the prism, but satisfactory rsults can sometimes be had by scraping all the old foam off the prism and then scraping off the wrinkled paint and bad aluminum coating. OM-1 (starting around serial number 1,110,000) were made WITHOUT this prism foam. Unfortunately, when the 1 became the 1N, the factory started using prism foam again. John http://www.zuiko.com Link to comment Share on other sites More sharing options...
ben_ford2 Posted July 14, 2007 Author Share Posted July 14, 2007 Ah, mine is 6xxxxx, so that explains that. Thank you John, that was a very comprehensive answer. What kind of figure would you be looking at for the replacement vs. the scraping of the foam? Link to comment Share on other sites More sharing options...
davidng Posted July 15, 2007 Share Posted July 15, 2007 A couple of years ago the prism of my girlfriend's OM-1 contained something moving inside the viewfinder. It was a small green caterpillar. Don't ask how it hot there. In my own Canon FTb viewfinder I occasionally saw small mites strolling up and down. Things happen sometimes. Link to comment Share on other sites More sharing options...
john_hermanson2 Posted July 15, 2007 Share Posted July 15, 2007 The pentaprism (LC4086) is a long discontinued part and would have to come out of a used body. OM-10, G, 20, 40, and PC also use the same prism. Normally it adds $49 to the price of an overhaul. When the affected area is scraped off and cleaned thoroughly with denatured alcohol, it retains most of it's reflectivity. You DO see a fine black line between the good and bad areas though. John www.zuiko.com Link to comment Share on other sites More sharing options...
tim_kohlman Posted July 16, 2007 Share Posted July 16, 2007 I've been told OM-10's are perfect to find a replacement prism since they didn't use mirror foam and you can probably find a dead OM-10 on ebay for $10 or so. Link to comment Share on other sites More sharing options...
john_hermanson2 Posted July 18, 2007 Share Posted July 18, 2007 Exactly. OM-10, OM-G, OM-20, OM-PC, OM-40 all made without prism foam. John www.zuiko.com Link to comment Share on other sites More sharing options...
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