The newer Acute-matte screens are brighter than the old screens, thus fooling the exposimeter of metered prisms not calibrated for AM. I think the error is something like one stop. You can't use the cameras without a screen (well, you can but you can't focus!). It is possible to recalibrate the old prisms, I think the best bet is an authorised service man.Originally Posted by BWGirl
You don't have to remove the prism to change backs, but you must remove the back to change viewfinders.