1. The measurement is taken from the film plane to the subject. 2. It was inspired by the film Planes , Trains and Automobiles starring Steve Martin. 3. M39 LTM mount with flange to film plane distance 28.8 mm not applicable. 4. Both the lens and the film planes are separate and can be moved independently. 5. The bellows provides a flexible, dark extension between the film plane and the lens. 6. Photographing from the ground, perspective can be eliminated by keeping the film plane parallel to the building. 7. Using a focal-plane shutter, exposing the whole film plane can take much longer than the exposure time. 8. Due to Petzval field curvature, the film plane upon which a lens focuses may not be a literal plane. 9. The cameras were coupled rangefinders, but had a unique focusing mechanism that moved the film plane instead of the lens. 10. Due to the mechanical compression the elastomer film contracts in the thickness direction and expands in the film plane directions. 
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