CPC G02B 13/007 (2013.01) [G02B 13/003 (2013.01); G03B 17/17 (2013.01)] | 20 Claims |
1. An optical system, comprising:
in order from an object side of the optical system to an image side of the optical system:
a first lens group comprising a power prism that includes a first surface, a second surface, and a third surface on an optical axis of the optical system, wherein the first surface is a transmissive aspherical surface that provides positive refractive power for the prism, wherein the second surface is a reflective surface that folds the optical axis of the optical system, and wherein the third surface is a transmissive surface; and
a second lens group comprising in order from the object side to the image side:
a first lens with positive refractive power,
a second lens with negative refractive power;
a third lens with negative refractive power; and
a fourth lens with positive refractive power; and
wherein the optical system satisfies the conditional expression:
0.6<B/A<2.3,
where A is power of the optical system, and B is power of the first lens group.
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