Nikon F4 - Manual (Page 161)

Nikon Repro-Copy Outfit PF-4
Enables you to make high-quality photographic copies of
photographs, illustrations, drawings or diagrams,
'With Nikon High Speed Battery Pack MB-21, use of Nikon
Camera Holder Adapter PA-4 is required.
Nikon Macro Adapter Ring BR-2A
Fits between the camera and lens to enable lenses to be
mounted in reverse; an inexpensive means of obtaining a rela­
tively high reproduction ratio. The BR-2A also increases the
working distance for normal or wideangle lenses.
Nikon Focusing Stage PG-2
Simplifies close-up focusing when using a tripod-mounted F4,