Quote Originally Posted by cparrish View Post
Yeah, I saw that site. And that's part of my confusion. The camera shown there is like every other Belfoca out there. It has two sliding covers over red lenses on the back. (still not sure what these are called). Mine only has one. Plus, if you notice, the Belfoca pictured on the site you mentioned has a shutter release button that looks completely different from the one I have. Mine looks just like the one in the picture I posted. Confused yet?
The windows ("red lenses") on the back of some cameras are there because they allow you to read the frame numbers on the backing paper for the film. You use those numbers to ensure that you wind the film the correct amount between shots, and to keep track of how many shots you have taken or have left. Some cameras have sliding covers for those windows, while others just rely on the darkness of the glass in the windows and the other light seals in the camera.

120 film is designed to permit a variety of different sizes of negatives. It is 6 cm wide, but various cameras are designed to shoot negatives that are different lengths - 6cm x 4.5cm, 6cm x 6cm and 6cm x 9cm being three popular formats. To accommodate this, there are three sets of numbers printed on most backing paper - each set of numbers is a different distance from the edge of the backing paper. The red lenses are designed to reveal the set of numbers that coincides with the size of negative produced by the camera.

A few cameras allow multiple formats. For example, some cameras have masks and other features that allow you, for each roll, to choose between exposing 8 negatives that are 6cm x 9cm each, or 15 or 16 negatives that are 6cm x 4.5cm each. Those multiple format cameras need separate windows for each format. If your camera only has one window, it was designed to produce just one size of negative.

It is not unusual for there to have been several models of a particular camera made over a period of time, with only small differences in features distinguishing each model. Websites that collect information on the various models of older cameras rarely show pictures of all the different models.