US 4,768,052 A · Focus detecting device

Abstract

A focus detecting device capable of correcting an error, between an in-focus position of a photographic lens detected by a focus detecting means and an image field position affording the best image. Focus detection is made using plural focus detecting areas provided on and off the optical axis of the photographic lens, to obtain an in-focus position. Then, the thus-obtained in-focus position of the photographic lens is corrected using an appropriate correction value out of those preset and stored in a ROM in the lens according to whether the focus detecting area used in the focus detection is an axial or off-axial area, or according to the focal length of the photographic lens as well as the photographing mode. And the photographic lens is thereby set to the best image field position.

Claims10

Dependent claims

A focus detection device for use in a camera system including an objective lens, comprising:

means for measuring the luminance distribution of a plurality of divided areas of an objective field to be photographed to produce a plurality of luminance distribution signals in correspondence to said areas;
means for producing a plurality of correction data signals each relating to aberrations of the objective lens in each areas;
means for determining the weights of the plurality of correction data signals to produce a plurality of weight signals;
and
means for performing a focus detection calculation on the basis of the plurality of luminance distribution signals, the plurality of correction data signals, and the plurality of weight signals to produce a resultant focus detection signal.

2 more elements

A focus detection device for use in a camera system including an objective lens, comprising:

means for receiving light coming from a plurality of divided areas of an objective field to be photographed, including a plurality of light receiving elements located at a plurality of positions different from each other, the plurality of light receiving elements producing a plurality of luminance distribution signals each corresponding to the luminance distribution of respective areas;
means for selecting one of the plurality of light receiving elements;
means for producing a plurality of correction data signals each relating to aberrations of the objective lens in each areas;
means for determining the weights of the plurality of correction data signals to produce a plurality of weight signals;
and
means for performing a focus detection calculation in accordance with a predetermined algorithm on the basis of a luminance distribution signal of the selected light receiving element, the plurality of correction data signals, and the plurality of weight signals, to produce a resultant focus detection signal.

3 more elements

Dependencies are inferred from the claim text.

Focus detecting device

Life of this patent

Focus detecting device

Life of this patent

Abstract

Claims10