Focus control device having improved sensitivity characteristics

A focus control device comprising:

• a first sensor means arranged to detect an extent of manipulation of a focus operating means to produce a lens displacement command signal;
• a second sensor means arranged to detect a current position of a focusing lens within a focusing range of the lens to produce a signal indicative of a current lens position;
• a comparator arranged to compare the output signals of said first and second sensor means to produce a servo control signal according to a difference between the two signals thereby to control the displacement of said focusing lens;
• an output signal characteristics converting means for varying said servo control signal so that said focus operating means operates to focus the focusing lens on an object with a substantially linear response over an entire stroke range between the nearest and infinite ends of said focusing lens;
• and
• an operation mode selector means for switching a mode of operation of said focus control device to and from a first operation mode in which the output signal of said first sensor means is imparted with said output signal characteristics by the output signal characteristics converting means, a second operation mode in which the output signal of said first sensor means is inverted after imparting said output signal characteristics thereto by said output signal characteristics converting means, and a third operation mode in which the output signal of said first sensor means is sent out bypassing said output signal characteristics converting means.