An optical apparatus includes an optical system for performing variable power
by one lens group or integrated lens groups; a variable optical-characteristic
element; a drive circuit for driving the variable optical-characteristic element;
and a picture element, wherein the apparatus is constructed by providing a predetermined
resolution chart with a known distance, feeding drive information to the variable
optical-characteristic element in accordance with the distance, photographing images
of the resolution chart, and adjusting and fixing the position of the picture element
so as to substantially maximize the contrast of the images.