A viewing optical system of an optical apparatus has an objective system for
forming
an image of an object and an eyepiece system for enlarging and directing the image
to the pupil. The viewing optical system also has a hologram combiner comprising
holograms of the volume type, phase type, and reflective type and having optical
power for constructing a surface which is optically equivalent to the image surface
at a different position than the image when viewed from the pupil. The system also
includes an information display means for displaying information at the position
of the equivalent surface, wherein the hologram combiner transmits light from the
image and reflects light from the information display means so as to allow viewing
of an image together with the information display overlaid onto the image.
