Optical system and imaging apparatus

An optical system comprising:

• a first lens L1 having negative refractive power;
• a second lens L2 having negative refractive power;
• a third lens L3 having positive refractive power;
• and
• a fourth lens L4 having positive refractive power, the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 being disposed in this order from an object side, wherein
• the optical system satisfies a following condition:
• −0.2≤f/EXP (1)
• where
• f is a focal length of the optical system, and
• EXP is a distance on an optical axis between an exit pupil and an imaging plane in the optical system when a direction from the object side to the imaging plane is defined as a positive direction, and
• wherein the optical system satisfies a following condition:
• 0.5≤f1/f2≤1.5 (2)
• where
• f1 is a focal length of the first lens L1, and
• f2 is a focal length of the second lens L2.