Last week we had some interesting questions about how the rackover viewing system worked on the Vinten Model H camera. We weren’t sure our explanation was clear enough, so we thought we would show a few pictures that better demonstrate how this fascinating internal rackover system works.
The 1st image illustrates the basic layout of the optical system. The taking lens is supported by the turret. The image the taking lens captures either falls directly on the film through the aperture plate, or, if racked into the ground glass position, the image is relayed through prisms to the viewfinder optics in the door.
The 2nd image shows the combined aperture plate/ground glass mount and rack gear that operates the rackover mechanism. A control knob at the back of the camera operates a pinion gear that moves the entire aperture plate/ground glass mount between its 2 positions.
The following 4 images show an exaggerated path that the aperture plate/ground glass mount moves as it travels between the taking position and the viewing position. The last image shows the ground glass in the viewing position inside a recess in the camera door.
