Am I compensating for my newer screen and older metered prism

[Gregarpp]

I have a 500CM with the newer brighter screen. I also have the older 45° metered prism.

I took some readings today with my light meter and determined there was 1 stop difference.

If I am using 100 speed film, I would set the meter to 50 speed to compensate for the brighter focus screen?

Does 1 stop seem normal?

 

[wbulte]

On my PME it is indeed a 1 stop difference between a AM and a old style screen.