Bruce,

Meter a light source with the Mamiya screen in place then do the same with the Beattie screen. Note the difference in readings and apply the appropriate compensation to the AE prism. This will save on a costly recalibration.

By Bruce Harrison on Thursday, February 26, 2004 - 01:40 pm:

I have just bought a beattie screen for my 645 Pro with 401 metered prism, however the instructions say that the light meter MAY need to be recalibrated! Shurly it either will or it wont! Has anyone else fitted a Beattie screen and if so did they have to recalibrate the meter or did they simply adjust by altering the ISO setting?