PURPOSE: To perform more accurate focusing with a smaller information capacity (bit number) by compensating the variable backlash for setting of individual interchangeable lenses and allowing the camera body side to take charge of data of a common part when data required for this compensation is outputted from the interchangeable lens side.
CONSTITUTION: When the backlash quantity in a lens due to a mechanism from a following-up shaft 14 to a focus lens, the backlash quantity due to play of engagement between the following-up shaft 14 of the lens and a camera-side driving shaft 58, and the backlash quantity from a camera-side motor MO to the driving shaft 58 are denoted as BL, BC, and BB respectively, a backlash quantity BT of the whole of this system is equal to BL+BC+BB. Deviations of backlash quantities of individual lenses from a backlash quantity BL0 in the lens of a specific lens as the reference are stored as data BLD concerning backlash in an ROM for the purpose of reducing the number of bits of data. Consequently, this data is 0 in case of the reference lens.
EGAWA TAKESHI
ISHIKAWA NORIO
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