Weird OM-1 viewfinder reflections - any ideas?

[Steveh]

Hi all - I've just taken delivery of an OM-1 bought cheap on Ebay, which looks to be in decent nick, but there seems to be something going on with the finder/pentaprism I wondered if anyone had seen before in an ageing SLR.

When I look through the finder with a window or light source behind me there are reflections of my shoulder/what's behind me in the top left hand corner of the finder. When I switch to my left eye the reflections go, I assume because my nose is blocking the light. The problem is the same with the lens cap on or off, mirror and focusing screen look fine.

Any thoughts on what this might be? Is there a lining/coating inside the finder that might have worn away? Something to do with rotting foam? Problems with the pentaprism coating?

All suggestions welcome!

 

[Chriscrawfordphoto]

It is the foam on top of the prism rotting. Olympus used a piece of foam between the prism and the metal bracket that holds the flash-socket on top of the prism, and time showed that this foam rots and damages the top of the prism, causing the reflections you see. It is not repairable, but the prism can be replaced. If anyone has an OM-1 or OM-2 that has not shown the symptoms yet, the prism foam can be cleaned out to prevent damage.

 

[nobbylon]

Steve, sounds to me like the foam had indeed affected the prism and someone has scraped it off and along with it some of the coating on the prism. It's very easy to take the top off and have a look. Let me know if you need the instructions. I have a link somewhere,
regards john

 

[Steveh]

B*gger! Thanks guys. So the damage wouldn't be visible in the viewfinder when looking through it, just the reflections when light's coming from an angle?

 

[nobbylon]

If the foam is still in there and has eaten away the coating, then chances are it will have black out splodges at the bottom of the finder when you look through. If its been removed and the prism polished where the coating used to be, then that's what I believe is causing the odd reflections.

 

[Steveh]

If the foam is still in there and has eaten away the coating, then chances are it will have black out splodges at the bottom of the finder when you look through. If its been removed and the prism polished where the coating used to be, then that's what I believe is causing the odd reflections.

No splodges, but having peered into the finder a bit more there are some really odd reflections going on, so it sounds like it may be exactly that - bits of the pentaprism having been polished/removed. Oh well!

Now I have to decide whether to make a fuss with seller who said the camera was in "excellent condition" 🙄.

Do you still have those nice om-1s for sale?!

 

[Chriscrawfordphoto]

THe prism from the OM-10 is the same as the one in the OM-1, and the 10 never used foam, so many people buy dead OM-10's on ebay and take their prisms to fix their bad OM-1's. Even working OM-10 bodies go cheap on ebay

 

[photovdz]

best way is to have it serviced by camtech (john H), it will come back better than new...
otherwise I have someone here in belgium who's not bad and cheap... photoclinic.

rotten foam in the prism is a typical om1/2 problem...

 

[hans voralberg]

It is a bit distracting but I have a OM-1 that have half of the coating damaged, still take good pics 😉 And it complement the battered exterior well lol