Patent ID: 7276686
Filing Date: 2007-10-02
Classification: G03B

Abstract:
1. A method for detecting a shutter opening angle of an adjustable rotating shutter mounted in a film camera which comprises a circular segment or circular sector shaped shutter vane driven through a shutter shaft by a shutter motor, and a shutter adjustment vane mounted coaxial with the shutter vane and adjustable relative thereto by means of a shutter adjustment vane motor, the method comprising: detecting an absolute position of the shutter vane and an absolute position of the shutter adjustment vane with a resolution of n steps during one revolution of the rotatable shutter, and determining the shutter opening angle (α) a of the rotatable shutter ( 1 ) from the equation  wherein  P  P wherein when the value of angle α is less than 0° the value is increased by 360° as long as the resulting value is greater than or equal to 0° or when the value of angle α is greater than or equal to 360° the value is reduced by 360° as long as the resulting value is less than 360°.