Optical system, and stereoscopic image photographing apparatus having the same

An optical system, comprising:

• a pair of front optical components, each of said pair of front optical components having an optical power;
• an optical member for superposing respective optical axes of said pair of front optical components on each other;
• a rear optical component disposed such that the superimposed optical axes coincide with an optical axis of said rear optical component, said rear optical component including, on a most object side thereof, a lens unit arranged to move during focusing;
• and
• shutter means capable of independently controlling amounts of transmission of light fluxes respectively entering said pair of front optical components from an object,
• wherein said optical system forms parallactical images in a time-series manner by causing said shutter means to alternately change the amounts of transmission of light fluxes respectively entering said pair of front optical components from the object,
• wherein no lens unit is present between said optical member and said rear optical component.