Patent ID: 9013607
Filing Date: 2015-04-21
Classification: G02B,G03B,H04N

Abstract:
1. An optical instrument, comprising: a ring member which is arranged to be rotatable with respect to a lens barrel, and also to slide in an optical axis direction; a movement mechanism for slide movement of the ring member to a first position or a second position in the optical axis direction, an encoder that generates signals in accordance with a rotation operation of the ring member; a position detection circuit for determining positional change accompanying slide movement to the first position or the second position by the movement mechanism; a clock counter, wherein responsive to a determination of a positional change of the ring member to the first position or the second position accompanying the slide movement, a value of the clock counter is reset, and otherwise, responsive to a determination of no positional change of the ring member to the first position or the second position accompanying the slide movement, a value of the clock counter is incremented, and