Exposure control system and a motion picture camera using the same

A motion picture camera, comprising:

• a. rotary shutter,
• b. driving means to revolve said rotary shutter,
• c. openable and closable switching means for driving and stopping said driving means,
• d. stopper means rotatable in coaction with the shutter, said stopper means having a first stopper which constrains said shutter to stop at an exposure position to allow passage of object light and a second stopper for constraining the shutter to stop at a light blocking position to block passage of object light,
• e. trigger means operable from outside of the camera for controling the actuation and stopping of said camera,
• f. a release means controlled by said trigger means, having:
• blocking means shiftable between an engagement position in which said blocking means can engage said stopper means and forcibly stop the revolution of the shutter and at the same time can keep said switching means open, and a non-engagement position which allows the revolution of the shutter and at the same time can keep said switching means closed,
• biasing means to continuously bias said blocking means toward said engagement position, and
• electromagnet means which when magnetized shifts the blocking means to said non-engaging position in opposition to the biasing power of said biasing means,
• g. control means to control said electromagnet means, having:
• power supply means to supply magnetizing current to said electro-magnet means in coaction with said trigger means,
• first shutter position detection means to detect shifting of said shutter to an exposure position and disable said power supply means for coupling said blocking means with said first stopper,
• resetting means for reenabling said power supply means after a lapse of a prescribed period of time,
• second shutter position detection means for detecting the shift of said shutter to a light blocking position and disabling power supply means and engaging said blocking means with said second stopper engaged;
• and
• mode selector means switchable between an ordinary motion picture photographic mode in which the shutter is continuously revolved, a single frame photographic mode in which said shutter is stopped at a light blocking position every time the shutter revolves once, and a long exposure photographic mode in which the shutter is temporarily stopped at an exposure position having said mode selection means;
• a mode selector member,
• a regulator means coupled to said first and second shutter position detector means and coactive with said mode selector member, and
• h. timer means coupled to said resetting means for setting a reset period for said resetting means;
• said regulator means, when said selector means is switched to the ordinary photographic mode by said mode selector member, nullifying the operation of said first and second shutter position detection means during the operation of the trigger means, and rendering said second shutter position detection means operable effectively only when the operation of the trigger means is completed;
• said regulator means when switched to the single frame mode nullifying the effect of said first shutter position detection means only while said trigger means is operating;
• said regulator means when switched to a long exposure mode nullifying the effect of said second shutter position detection means during the operation of the trigger means and actuating said second shutter position detection means when the operation of said trigger is completed.

A motion picture camera, comprising:

• a. a photographic optical system,
• b. exposure adjusting means, including
• an exposure correction circuit having a photoelectric conversion means to generate an electric signal corresponding to the amount of object light passing through the photographic optical system, said circuit producing a signal corresponding to the output of said photoelectric conversion means, and
• diaphragm means responsive to the output of said exposure correction circuit and for controlling the amount of light passing through said photographic optical system,
• c. a rotary shutter,
• d. driving means to revolve said shutter,
• e. switching means to drive and stop said driving means,
• f. stopper means rotatable with said shutter and having a first stopper for holding said shutter at a position which passes object light and second stopper means for holding of said shutter at a light blocking position in which it blocks light from the optical system,
• g. a trigger operable from outside of the camera,
• h. release means controlled by said trigger, and having:
• blocking means shiftable to an engaging position in which said blocking means engages said stopper means to forcibly stop the revolution of said shutter and at the same time to keep said switching means open, and to a nonengaging position in which said blocking means allows revolution of said shutter and at the same time closes said switching means,
• biasing means for continuously biasing said blocking means into the engaging position, and
• electromagnet means which, when magnetized, shifts said blocking means to said nonengaging position against the biasing force of said biasing means,
• i. regulator means to control said electromagnet means and having:
• power supply means to supply magnetizing current to said electromagnet means in response to said trigger means,
• first shutter position detection means to detect shifting of said shutter to said exposure position for interrupting the supply of energy from said power supply means and to engage said blocking means with said first stopper means,
• resetting means to recontinue the energy supply from said power supply means, which has been stopped to said first shutter position detection means, after a lapse of a prescribed period of time,
• second shutter position detection means to detect the shifting of said shutter to said light blocking position for interrupting the supply of energy from said power supply means and engage said blocking means with said second stopper means engage and
• mode selector means settable to an ordinary photographic mode for continuously revolving said shutter and a single photographic mode for stopping said shutter at the light blocking position during as well as to a long exposure photographic mode for temporarily stopping said shutter at said exposure position, said selector means including:
• a mode selector member, and
• control means actuated in coaction with said mode selector member, and
• j. timer means electrically connected to said resetting means and said exposure correction circuit for setting the period of time required for resetting of said resetting means, and for controlling said resetting means and correcting said exposure correction circuit;
• said control means, when said mode selector member is set to the ordinary photographic mode, nullifying said first and second shutter position detection means while said trigger means is in operation and effectively actuating the second shutter position detection means only when the operation of the trigger means is completed;
• said control means, when said mode selector member is set to the single frame mode, nullifying the first shutter position detection means only while the trigger means is in operation;
• said control means when said selection member is set to the long exposure mode, nullifying the second shutter position detection means while the trigger means is in operation and actuating said second shutter position detection means when the operation of the trigger means is completed.