According to St. Ansel's "The Camera", a given focal length lens will project the same size subject on the negative, regardless of format. For example, if, on a 35mm negative, a 50mm lens creates an image that is 1/2 inch high, the same length lens (50mm) will create an image that is 1/2 inch high on 120 film. Difference being that the image will take up a larger percentage of the negative on 135 than on 120.
Bill
