Patent ID: 8427763

Claim:
A lens system comprising: on a side closest to an object, a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object; and on a side closest to an image, a cemented lens constructed by cementing together a positive lens and a negative lens in order from the object; wherein the lens system satisfies the following conditional expressions: ( n 1+ n 2)/2>1.49 (ν1+ν2)/2>60 where n 1 and ν 1 denote a refractive index and an Abbe number of the first lens component at d-line, respectively, and n 2 and ν 2 denote a refractive index and an Abbe number of the second lens component at d-line, respectively, and further comprising: a front-side negative lens component having a negative refractive power, an aperture stop, a rear-side negative lens component having a negative refractive power, and a rear-side positive lens component having a positive refractive power in order from the object between the second lens component and the cemented lens.