ruined nikon F eye level finder?

[mikejd80]

I have a question about a Nikon F standard finder i recently got. I see that the inner wall surfaces of the pentaprism all show white dots, but they seem uniformly formed, do not look like fungus or other taint, the finder looks mint. I am wondering whether anybody has ever seen this before, or maybe there is really something wrong with the finder? maybe desilvering? but i see no other dirty stuff inside the finder. if it is the silver coating peeling off, they are so oddly separated.

 

[E. von Hoegh]

The prism needs re"silvering" It's actually aluminium. There's a thread on it here, somewhere.

edit - (there was a url link here which no longer exists)

How does it appear when you look through the prism?

 

[lxdude]

The pattern reminds me of 60's "Op-art".

 

[Yashinoff]

It is actually probably the paint on the silvering starting to bubble off, think of "schniederitus". If the silvering itself has been affected the viewfinder image will appear hazy. I have a couple of prisms where this has happened and they still work fine. On the other hand I have several prisms where the silvering has degraded without any bubbling of the black backing paint. If it works it works, if it doesn't it doesn't.

 

[E. von Hoegh]

It is actually probably the paint on the silvering starting to bubble off, think of "schniederitus". If the silvering itself has been affected the viewfinder image will appear hazy. I have a couple of prisms where this has happened and they still work fine. On the other hand I have several prisms where the silvering has degraded without any bubbling of the black backing paint. If it works it works, if it doesn't it doesn't.

If you can see through the silvering to the paint bubbling off, then the silvering is bad, too.

 

[Yashinoff]

If you can see through the silvering to the paint bubbling off, then the silvering is bad, too.

I'm not completely sure, since the black areas are where paint is still adhered to the silvering. :confused: I don't think the silvering is generally thick enough to be anywhere close to opaque.

Edit: take that back, but it doesn't change much. What we're seeing bubbles on is the top front of the pentaprism, which isn't actually used in viewing anyway.