Patent ID: 9417436
Filing Date: 2016-08-16
CPC Classification: G02B

Claim Text:
1. An optical system, comprising, in order from an object side to an image side: a first lens unit having a positive refractive power; and a second lens unit having a positive refractive power, the second lens unit comprising, in order from the object side to the image side, a front unit, an aperture stop, and a rear unit having a positive refractive power, the first lens unit comprising a negative lens that has a convex surface facing the object side and is arranged closest to the object side, and three or more positive lenses on the image side of the negative lens, wherein the front unit and the rear unit are configured to move during focusing, and wherein the following conditional expression is satisfied: where PL denotes a distance, on an optical axis, from a lens surface on the object side of a second positive lens counted from the image side among the three or more positive lenses comprised in the first lens unit to a lens surface closest to the image side of the first lens unit, and D