초록 ▼

An automatic focusing device for moving a photographic lens to an optimum focusing position by detecting an object image contrast signal that changes with the varying position of the photographic lens. The device stops the photographic lens while it is being moved between an infinite distance photog

An automatic focusing device for moving a photographic lens to an optimum focusing position by detecting an object image contrast signal that changes with the varying position of the photographic lens. The device stops the photographic lens while it is being moved between an infinite distance photographing position to a least distance photographing position when the level of the detected contrast signal becomes less than a threshold level. The invention compares a first signal, which is set to correspond to a position at which the photographic lens is to be stopped, and a second signal, which is generated when the contrast signal level is less than the preset threshold level.

대표청구항 ▼

An automatic focusing device for moving a photographic lens to an optimum focused position comprising means for optically detecting object image contrast and means for generating a contrast signal based on said optically detected object image contrast, said contrast changing with varying positions o

An automatic focusing device for moving a photographic lens to an optimum focused position comprising means for optically detecting object image contrast and means for generating a contrast signal based on said optically detected object image contrast, said contrast changing with varying positions of the photographic lens comprising: lens motion stopping means for stopping said photographic lens after it has been moved from a starting position no more than once between its infinity distance photographing position and its least distance photographing position when the level of said contrast signal is less than a threshold level of said detected contrast signal, whereby the lens is not repeatedly cycled between its infinity and least distance positions where the object being photographed has little or no contrast.