Chris,
When I use mine I have my eye almost in the little square opening
(while I`m aiming for the wide rim for 35mm mask)
but it won`t leave a mark on your head or anything, I think that the
ROSOL is the best finder and also more lightweight then anything else and it works on 35/50/90 and 135mm fields
I only want a VIOOH for collectors reasons, I use the
ROSOL now full-time on my everyday camera *1945 "Half Race" Leica IIIC to IIIFBD conversion*
(see below)
First time I`ve ever used this type of finder since I started Leica and I find it the most comfortable and also light weight and also quite the conversation piece
🙂
It does stick out like a inch or so in the back, but you hold it to where you are comfortable and adjust your distance with the backpiece which slides up and down, real easy!
Only downside is these are also collectable and while they used to be $50 items, are now always fought for over the evilbay, with some luck still you can find them under $100 - Canon also made one as well in the 1950`s, but it`s pretty rare and is also in the collectable bracket price
Tom