Nikon introduce the electronic F3's as the F2's successor, only the shutter speeds are electronically controlled, the film transport and mirror-box are still mechanically operated.  This is a beautiful piece of act as it was the work of the Italian industrial designer Giorgetto Giugiaro!  Like all the Nikon's professional series, it has a die-cast body made of copper-silumin alloy, the thickness of the casting wall varies between 1.4mm and 2.0mm, the outside covers and the back of the camera are made of brass.  This camera is with a special finder with the additional denotation "HP" (high eyepoint) which allowing a complete view of the finder image from up to a distance of 25mm between eye and eyepiece, hence, most suitable for persons with glasses.
Nikon F3hp SLR
Nikon MK-1 Firing Rate Converter was designed by Nikon to address some weaknesses present in the MD-4, it attaches to the base of the MD-4, provides a trigger button for use in vertical format shooting with additional function to provide three firing rates of either 1; 2; or 3 frames per second or unrestricted speed as determine by the motor drive operation, see below: