Exposure control system for single lens reflex cameras
AssigneeMinolta Camera Kabushiki Kaisha
InventorSeiji Yamada
Life of this patent
Estimating the term…
Abstract
A through-the-lens type automatic exposure control system controls exposure time in accordance with an object light representative signal stored in a storage device prior to a shutter actuation, with respect to exposure time faster than a given value, and in accordance with the output of a light measuring circuit measuring the object light passing through the camera objective and reflected from a film surface, with respect to exposure time slower than the given value. In response to a manual operation, the light signal is stored in the storage device independently of camera release operation, with the exposure time being controlled in accordance with the stored signal regardless of the exposure time.
Claims13
An automatic exposure control system for a single lens reflex camera having a reflex mirror and a focal plane shutter member, comprising:
- first light measuring means for generating an output in response to the measurement of light from an object through the camera objective with the reflex mirror at a viewing position thereof;
- storage means for storing said output;
- release means for storing said output in response to a shutter release operation;
- manually operable means for storing said output;
- second light measuring means for measuring the light from the object passing through the camera objective and reflected by the surface of a film;
- shutter control means for controlling the closure of said focal plane shutter member;
- switch means for selectively connecting said shutter control means with said storage means and said second light measuring means, said switch means switching the connection from said storage means to said second light measuring means when said focal plane shutter member moves a given distance;
- and
- prevention means for preventing the switching from said storage means to said second light measuring means when said manually operable means is operated.
An automatic exposure control system for a single lens reflex camera including an objective lens, a focal plane shutter member, and a reflex mirror movable between a viewing and a photographic position and having a semi-transparent portion, said system comprising:
- photoelectric means receiving light from an object to be photographed through said objective lens and said semi-transparent portion of said reflex mirror with the latter at said viewing position, and receiving the light from the object passing through the objective lens and reflected from the film at the focal plane of said objective lens with said mirror at said photographic position;
- light measuring means including said photoelectric means for generating a light signal as a function of the light received by said photoelectric means;
- storage means for storing said light signal;
- first interruption means for preventing said storage means from storing said light signal in conjunction with a camera shutter release operation;
- delay means for delaying the closure of said shutter member;
- and
- switch means for connecting said delay means with said storage means at the first stage of a camera exposure operation, and subsequently switching the connection of said delay means to said light measuring means when a given time has passed.
An automatic exposure control system for a single lens reflex camera having an objective lens, a focal plane shutter movable substantially in the focal plane of said objective lens, and a reflex mirror movable between respective viewing and photographic positions;
- said system comprising:
- light measuring means for generating a light signal as a function of light from an object to be photographed and traversing said objective lens, said light measuring means including light receiving means for receiving the light at both said viewing and photographic positions of said reflex mirror, with said light receiving means receiving the light reflected from said focal plane at least when said reflex mirror is at said photographic position;
- storage means for storing said light signal;
- delay means for delaying the closure of said shutter;
- and
- switch means for selectively connecting said delay means with said storage means and said light measuring means.
Dependencies are inferred from the claim text.