Optical system and imaging apparatus

An optical system comprising:

• two imaging optical systems disposed symmetrically with each other;
• two holders including one holder to hold one imaging optical system, and other holder to hold the other one imaging optical system, each holder having a first hole and a second hole;
• and
• two shaft members including a first shaft member and a second shaft member, the two shaft members disposed between the two holders,
• the two holders being disposed such that the first holes are opposed to the second holes,
• the first shaft member being held by the first hole of the one holder, and the second shaft member being held by the second hole of the one holder,
• the first shaft member being disposed in the second hole of the other holder with a movement of the first shaft member restricted in each direction perpendicular to a direction in which the first holes are opposed to the second holes,
• the second shaft member being disposed in the first hole of the other holder with the second shaft member movable in only a certain direction within a plane perpendicular to the direction in which the first holes are opposed to the second holes.