Diopters for Olympus OMs

[Strider]

I can see (sort of) I will need diopter eye cups for my Olympus cameras soon. I can find the eyecups on ebay, however, I am having some difficulty finding the diopter inserts. Any tips to locate a source will be appreciated.

 

[Rick A]

Which Oly(s) are you using? OM-3 & 4 have this built into the prism housing, I'm dont remember this on any of the other models.

 

[Strider]

I have the OM 10 and 2n.