The Diana camera is a so-called “toy camera” that originated in the 1960s, produced by the Great Wall Plastic Co. in Hong Kong. Production continued through the 1970s but ceased sometime thereafter.
The camera was produced under many names for different markets; some photographers may use the term “Diana” generically to mean any of the related Hong Kong models. Some were sold as premiums or promotional items (there is a Readers Digest version, for example). Most Dianas use 120 film but some versions of the camera take 620 film.
The lens is a simple plastic meniscus, giving noticeable corner blur, vignetting, and pincushion distortion in the resulting photographs. Light leaks are a possibility due to the flimsy back latch design; many users put black tape over the seams to make the cameras light-tight. Most Diana types expose a 4cm x 4cm image (less than the full height of the film), so a 120 roll will give you 16 frames. Focusing is done by twisting the lens to 3 zones, 4-6ft, 6-12ft, or 12ft to infinity. There are several variations in top-plate and lens-barrel style; some have fake light-meter windows and a few have flash sync.
~Description courtesy of Camera-Wiki