Automatic focal point adjusting device of ttl photometry system

Abstract

Abstract PURPOSE:To make the constitution compact and reduce the manufacturing cost of the titled adjsting device, by correcting the moving amount setting element of a focus ring in accordance with the image point moving amount of an object caused by the variable power of a zoom lens and setting the moving amount of the focus ring. CONSTITUTION:An object image having the same focal point as an image formed on an image pickup device 50 is formed on a focal plane Z2 by beam splitters D1 and D2. The object image is caught by a focal point detecting element 61 and the defocus amount DELTAp which is the sum of the deviated amount of focal point DELTAs and the moving amount of image point DELTAl, is detected. Moreover, an automatic focal point adjustment controlling section 60 corresponds to the zoom information N of a zoom ring 20 and the manification (m) and focal length (fe) of a variable power lens group E corrected in accordance with the moving amount of image point DELTAl are stored in the microcomputer of the controlling section 60. Then, the moving amount DELTAx of a focus ring 10 is set based on the relation from the detected value. Therefore, the constitution can be made compact and the manufacturing cost can be reduced in such a way.

Inventors

• 👤 Shoji Taguchi
• 👤 田口　昭司
• 👤 Hiroshi Shinohara
• 👤 弘 篠原

Bibliographic Details