This is a relative size comparison between the first generation 35mm full frame Sony a7R and this old 35mm SLR film camera. This is actually my daughter's camera and was residing peacefully in my attic.

The 'shadow' represents an offset where the sensor and film planes line up.

Pentax ME super was arguably one of the smallest 35mm SLR film cameras ever made. 5.2" (132mm) wide excluding hinge.