Well how about that
I never realised my glasses could be reversible.
So yes - I have glasses but I am asking suddenly because I moved back to rangefinder film cameras (essentially decided to stop displaying my collection and use them - but also have collected medium format too over the years ) from very modern digital with adjustable view finders and so thought nothing about it all as my eyes were changing over the years .
Suddenly I notice my right eye has changed a fair amount having just had my eyes tested 5 years later - and I cannot focus some of the cameras with my glasses on and none with them off and my prescription shows my own diopter for example in my right eye is +3.5 long distance and +2 short distance (reading , camera etc)
My left eye is less in all cases. Together in normal life - can't tell the change.
So one camera is worse than any other - the finder on an ETRS medium format Bronica fitted with a -1.5 diopter prism behind the eye piece.
I went to the chemist tried on those cheap reading glasses with the camera up to + 3.5 but not much use - and of course the -.1.5 was still in the finder. (I was going to go back with the prism out - but does where it sits in the finder mean a lot ? (IE: If I replace it with wearing a +2 pair of glasses IN FRONT of the eye piece - does that really tell me anything usefull?)
The optician said I need basically a +2 diopter with no glasses on - but the world via the internet at least seems to have run out of Bronica etr AEii +2 finder diopter prisms.
Someone else on here once suggested in another post making your own with one of those cheap pairs of glasses - so my real question and search and education is about that - the prism in the finder though is a lens glued to a lump of clear glass - so I wanted to separate that and re fix a +2 lens to the lump
Do I need the lump of backing glass (distance??) - anyway - its a new education subject for me and my eyes are not getting stronger - so to really enjoy life on these cameras it would be good to solve this little problem. All help and teaching appreciated tks. I meant to ask - what are minus sizes (-1.5) - are they also "magnifications" - if so where is zero start?