Spots on internal lens element.

[fidget]

I've recently bought an Ensign 12-20 with Ross-Xpress lens, circa 1954. It's in superb condition and looks mint to the naked eye.
Looking into the lens (from the front) using a magnifying glass (an old 50m lens) allows me to focus on the surface of each lens element as I move nearer/further to the lens. On the inside surface (I think) of the inside element I can see a fairly even spread of spots. These don't look like the onset of fungus, more like something has condensed on the lens. All the spots are completely transparent.

It may be old lubricant.

I've not pulled it apart yet, I will try a film in to check for other problems first.

Could it be some condensate? If it is, has anyone had any success in cleaning this sort of mark off?

Dave...

 

[edodo]

It could be lots of things like delamination in the lenses, they used organic glue back in the days which can deteriorate with time. It could be the coating that was too fragile and get eaten by moisture or rust. Post some pics maybe someone could help.

 

[fidget]

No success in photographing the spots yet. May be easier when the lens is apart.
In the meantime, I took it out today for test shoot on FP4+. (I just hate the feint numbering on this film, I need a magnifying glass and sometimes a torch to see the frame numbers!).
It's an Ensign 1220 with the Ross Xpress lens. It's very good. Can't see any reason to pull it apart at the moment.