According to the present invention, an optical apparatus is provided that
comprises a recording medium, a distance-detecting sensor, an
illustrated-guide selector, and an image-indicating device. The recording
medium stores illustrated-guide data for a plurality of illustrated
guides. The distance-detecting sensor detects distance information
relating to an observation target. The illustrated-guide selector selects
one illustrated guide from the plurality of illustrated guides, in
accordance with the distance information. The image-indicating device
displays information of the illustrated-guide data.