84 x 56 mm image area · 2 interactive lens diagrams
Fuji G690, medium-format rangefinders, folding cameras, and technical roll-film cameras | Nominal 84 x 56 mm film image area with a 101 mm diagonal
6x9 is one of the largest common 120 roll-film formats. Its usable frame is about 84 x 56 mm, giving a 3:2 aspect ratio similar to 35 mm full-frame but at far larger scale. The format appears in folding cameras, press and technical cameras, and rangefinder systems such as the Fuji G690, where the goal is a large negative without moving up to sheet film.
The large diagonal changes everything about the optics. Normal lenses sit around 100 mm, wide-angle coverage is demanding, and fast apertures become large and expensive. Rangefinder and view-camera-style systems can avoid some SLR mirror constraints, but lenses still need to deliver adequate sharpness, illumination, and distortion control over a 101 mm diagonal. Catalog entries in this class show medium-format design pushed toward the edge of roll-film coverage.