[. . . ] The Nikon Right-Angle Viewing Attachment DR-4 screws into the finder of any Nikon or Nikkormat 35mm SLR camera capable of accepting screw-in eyepiece accessories (see table for specific models and finder types). [. . . ] , are removed, then refer to the table for correct mounting procedure. F-801/N8008, F-801s/N8008s, F3 High-Eyepoint, F3/T, D1 Nikkormat FTN, FT2, FT3 Remove eyepiece or other accessory and adopter ring on the DR-4 before moiunting. Note that once the DR-4 is securely mounted on the camera, it can be rotated (i. Note: It is impossible to mount the DR-4 on earlier Nikon F model cameras because of their rectangular eyepiece frames. [. . . ] Note that the DR-4 is provided with a locking screw to secure the diopter setting; be sure to loosen this screw before attempting to make adjustments. [. . . ]