Medium Format Aspect Ratios
The selection of a medium format aspect ratio is a foundational technical decision that dictates the compositional framework and exposure volume of the session. This parameter determines not only the spatial relationship between the subject and the environment but also the absolute number of frames available per roll of 120 film.
Depending on the selected commission plan, clients may dictate the utilisation of 6x4.5, 6x6, or 6x7 formats. The following index outlines the mechanical specifications and structural characteristics of each ratio to inform your technical brief.
6x7
This is the primary and recommended medium format configuration for portraiture and editorial commissions. The 6x7 negative provides an elongated, expansive frame that closely mirrors the proportions of cinematic and traditional painting canvases. This wider structural format is engineered for capturing grand environmental portraits and incorporating complex spatial narratives within a single exposure.
Mechanical Specifications:
Available Systems: Pentax 67, Mamiya RB67 Pro-S
Exposure Capacity: 10 frames per 120 roll
6x6
The 6x6 format produces a geometrically symmetrical square negative. This aspect ratio forces a highly structured composition, inherently imposing a strict sense of equilibrium and visual balance. It is a classic medium format standard that requires rigorous compositional discipline from the photographer. The exposure count is moderately restricted, demanding deliberate execution and attention to detail for each frame.
Mechanical Specifications:
Available Systems: Yashica Mat-124G, Bronica S2A
Exposure Capacity: 12 frames per 120 roll
6x4.5
The 6x4.5 format serves as a structural compromise between the square 6x6 and the broader 6x7 ratios. It offers a slightly elongated rectangular frame that provides more lateral width than a square, yet maintains tighter boundaries than the 6x7 format. This format yields the highest exposure efficiency per roll, making it a pragmatic choice for sessions requiring a higher volume of distinct compositions without sacrificing the resolution inherent to medium format film.
Mechanical Specifications:
Available System: Mamiya 645 1000S
Exposure Capacity: 15 frames per 120 roll
