Apparatus for correcting focal point according to lens temperature

Abstract

An apparatus for correcting a focal point according to a lens temperature includes an operation unit, to which data concerning a distance between a focusing lens and an object, data concerning a distance of the focusing lens and a focusing screen, and data concerning a variation of a focal point of the focusing lens per temperature variation are inputted beforehand. When data on a desired magnification are inputted, the operation unit performs arithmetic operations on a focal point at a present temperature. According to the calculated data, adjusting means adjusts distance between the focusing lens and the object, and that between the focusing lens and the focusing screen. As the temperature of the focusing lens further changes, the operation unit continues calculating the variation of the focal point, and another adjusting means adjusts the focal points accordingly.

Dependencies are inferred from the claim text.