Automatic rangefinding device for use in a camera

An automatic focusing device in a photographic camera having a focusable objective lens comprising in combination:

• a source of illumination for illuminating at least a portion of an object to be photographed;
• means for activating said source to produce illumination;
• detector means disposed to receive illumination of the source reflected from the object and generate an output signal related to the amount of said reflected illumination;
• integrating means coupled to the detector means for producing a trigger signal when the total amount of reflected illumination received by the detector means reaches a predetermined value;
• timer means for measuring the time interval between activation of the source of illumination and generation of the trigger signal;
• converter means coupled to the timer means for generating a range signal as a function of the measured time interval;
• and
• focus control means coupled to said converter means so that the input thereof receives the output from said converter means so that said focus control operates the focusing movement of said objective lens in response to said inputted signal.

Apparatus for causing a lens system of a camera to be focused upon an object separated therefrom by an object distance, the apparatus comprising:

• a source of illumination for illuminating at least a portion of the object to be photographed;
• detector means disposed to receive illumination reflected from the object and generate an electrical output signal proportional to the amount of said reflected illumination;
• integrating means coupled to the detector means for producing a trigger signal when the total amount of reflected light received by the detector means reaches a predetermined value;
• timer means for measuring the elapsed interval between activation of the source of illumination and generation production of the trigger signal;
• converter means for translating the measured time interval into a range signal that corresponds to said object distance;
• and
• lens system adjustment means responsive to said range signal for focusing said lens system at the object distance.

A photographic camera including means for supporting a film unit at a film exposure plane, the camera comprising:

• a lens system adapted to be focused upon a remote subject;
• a shutter mechanism for controlling an exposure period wherein light is admitted into the camera through the lens system for exposure of the film unit;
• an electronic flash unit of predetermined intensity for illuminating the subject;
• a body release which actuates (a) the flash unit;
• and thereafter, (b) the shutter mechanism to initiate the exposure period;
• light sensitive means for detecting light emitted by the electronic flash unit and reflected from the subject and for generating an electronic output signal related to the reflected light so detected;
• integrating means coupled to the light sensitive means for producing a trigger signal when the total amount of reflected light received by the light sensitive means reaches a predetermined value;
• timer means for measuring a time interval in which the light sensitive means receives the reflected light from the flash unit;
• converter means coupled to the timer means for generating a range signal as a function of the measured time interval;
• and
• adjusting means responsive to said range signal for adjusting said camera lens system to focus said subject on the film exposure plane prior to initiation of the exposure period by said shutter mechanism.