Focal plate of camera

Abstract

Abstract PURPOSE: To obtain sufficient distance meaurement accuracy by arranging ruggedness of conical bodies near the focal plane of a focal plate and satisfying prescribed conditions. CONSTITUTION: A focal plate 1 is arranged with square bodies (circular conical bodies or the like) 3 of which the bottom faces are a focal plane, in contact with each other at the bases, so that the bottom surface of the plate 1 is a plane, spherical, aspherical or Fresnel shape. The angle α of inclination of the bodies 3 is so set as to satisfy 0.8f/10 4 (n-1)Δ≤α≤1.5/2(n-1)F, and when the length of the slopes of the conical bodies is so set as to satisfy A<3×10 -4 where the visual angle viewed through an eyepiece lens of the focal length f is defined as A. Here, F is the F value of a finder system, n is the refractive index of the focal plate and Δ is the required accuracy of distance measurement. Or α and A are so set as to satisfy 0.2f/10 4 (n-1)Δ≤α≤1.5/2(n-1)F, 3×10 -4 ≤A<8×10 -4 . Thereby, the sufficient accuracy of distance measurement is obtained. COPYRIGHT: (C)1982,JPO&Japio

Inventors

• 👤 Toshihiro Sasaya

Bibliographic Details