The Polaroid Big Shot has a simple mirror arrangement to facilitate focusing. Four small rectangular mirrors are fixed in a frame, with slanted mirrors at top and bottom, and two mirrors laying flat in between them.
When I received my Polaroid Big Shot, one of the mirrors in the rangefinder was no longer attached. The Big Shot Manual (download it here) says that focus is achieved when the lens is 39″ (100cm) away from the subject. So I’m going to start with that information. Here’s my crude setup:
I removed the range finder from the camera housing (4 screws total — open the film back and see the first 2 screws, then the range finder cover is hinged. There are 2 more screws inside holding the bracket).
Then I taped the mirror bracket to a light stand, and moved it 39″ (the focus distance to the lens) + 9.5″ (the distance from the lens to the rear of the range finder bracket) away from a white board.
On the white board, I drew a simple pattern that would give me something to line-up on. The range finder works by moving yourself and the camera forward or backwards, until the image (showing in the white square) moves and aligns with the image on the whiteboard. In this photo, you can see that my image is below, and to the right of the design drawn on the whiteboard. Since I’m the (presumed) proper distance from the whiteboard image, I need to adjust the mirror until the two images line up.
