As "s"1 is decreased, "s"2 must be increased. For example, consider a normal lens for a 35 mm camera with a focal length of "f" = 50 mm. To focus a distant object ("s"1 ≈ ∞), the rear nodal point of the lens must be located a distance "s"2 = 50 mm from the image plane. To focus an object 1 m away ("s"1 = 1,000 mm), the lens must be moved 2.6 mm farther away from the image plane, to "s"2 = 52.6 mm.