Focusing screen


New Member
I have a OM-10 which I occaisionally use with a 500mm mirror lens. I understand that the focusing screen cannot be changed like with thre OM-1 etc. Is there anyway of changing the screen or aiding focusing when using telephoto lenses?
I had tried to dis-assemble the OM-10 last year.

I found that if you want to change the focusing screen you have to open the top cover & remove the circuit board & pentaprism first....

It's not an easy job...