Patent ID: 7656454

Claim:
An image pickup apparatus comprising: a finder optical system configured to guide an observation beam to a finder window, the observation beam being a beam traveling from a photographing optical system and reflected by a main reflecting surface; and a first image pickup device configured to detect the observation beam and generate an image signal, wherein the finder optical system has a first reflecting surface that is one of a plurality of reflecting surfaces included in a pentamirror assembly of the finder optical system and reflects the observation beam; the first reflecting surface can change a reflection angle of the observation beam; and a path of the observation beam can be switched between a first optical path and a second optical path by changing the reflection angle of the first reflecting surface, wherein the first optical path is reflected by the first reflecting surface and directed toward the finder window, while the second optical path is reflected by the first reflecting surface and directed toward the first image pickup device, and an angle difference between the first optical path and the second optical path is equal to twice the difference between the reflection angle of the first reflecting surface for the first optical path and the second optical path.