dak
Newbie
I have recently purchased a nice Taron external viewfinder with framelines for 35/85 mm. Its optics, however, are so yellow (almost gold) that I wonder if there is no some thorium in it. I've heard about thorium in microscopes eyepieces. Any idea if it was used in camera finders as well, or it was always banned?
Phil_F_NM
Camera hacker
Viewfinder optics which are yellow were either done from the factory to increase contrast (this is usually in rangefinder optics) or due to aging balsam cement. If it is a non-RF viewfinder, it is probably just balsam cement aging, but it could be coating as well. Rare earth glass was very expensive and almost certainly not used in viewfinder optics, as they do not require the refractive index for image drawing, since they are only used for composition, not to project the image onto film itself.
Phil Forrest
Phil Forrest
mpaniagua
Newby photographer
Pretty unlikely, since, like Phil says, VF don't require the refractive properties that rare earth/radiotive elements provide.
I would say you are safe and won't grow a third eye
I would say you are safe and won't grow a third eye
Franko
Established
This is comforting to hear. One of these finders is more or less welded to my IIIf. No third eye yet but it's hard to explain my forked tongue.
dak
Newbie
I can live without a third eye, but a third arm would be handy when fiddling with all these bottom loaders and removable back cameras. Thanks, guys!