CPC G02B 9/34 (2013.01) [G02B 13/004 (2013.01); G02B 13/18 (2013.01)] | 20 Claims |
1. An optical imaging system, sequentially from an object side to an image side of the optical imaging system along an optical axis, comprising:
a first lens having positive refractive power;
a second lens having negative refractive power;
a third lens having positive refractive power; and
a fourth lens having negative refractive power,
wherein 1<TTL/To<2.5,
where TTL is a distance along the optical axis from an object-side surface of the first lens to an imaging plane of the optical imaging system, and To is a distance along the optical axis from a to-be-captured object to the object-side surface of the first lens.
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