1. The Nikon screen with the grid lines and the split image is the E screen. The R screen has the grid lines and the split image focusing aid.
Originally Posted by Ara Ghajanian
2. From what I understand, Nikon makes –3 to +2 diopters for the F3HP. This should cover both near-sighted and far-sighted people. However, unless you can actually try the diopter on your camera, it is not a simple task trying to calculate exactly which diopter will correct you particular vision problem. I use a +1.75 diopter reading glasses so I figured that a +2 diopter should help me. Wrong! The +2 diopter that I ordered made things much worse.