Photography optical system and image capturing unit

A photography optical system comprising, in order from an object side to an image side along an optical path, a first lens assembly, an aperture stop and a second lens assembly, each lens element of the photography optical system having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

• wherein a total number of lens elements of the first lens assembly is one to three, a total number of lens elements of the second lens assembly is five to eight, and there is no additional lens element disposed between the first lens assembly and the second lens assembly;
• wherein the first lens assembly comprises a first lens element closest to the object side, the second lens assembly comprises a last lens element closest to the image side, the photography optical system further comprises, in order from the first lens element to the last lens element along the optical path, a second lens element, a third lens element, a fourth lens element and a fifth lens element, and there is no additional lens element disposed between the first lens element and the fifth lens element;
• wherein the first lens assembly has positive refractive power, and the second lens assembly has negative refractive power;
• wherein the object-side surface of the first lens element is convex in a paraxial region thereof, the object-side surface of the second lens element is convex in a paraxial region thereof, the object-side surface of the third lens element is convex in a paraxial region thereof, the image-side surface of the third lens element is concave in a paraxial region thereof, and the object-side surface of the fourth lens element is convex in a paraxial region thereof;
• wherein a focal length of the photography optical system when corresponding to an infinite object distance is fL, a focal length of i-th lens element counting from the object side among the photography optical system is fi, a minimum value of fL/fi is MIN (fL/fi), a focal length of the first lens assembly is fA1, a maximum value among central thicknesses of all lens elements of the photography optical system is CTmax, a maximum value among axial distances between each of all adjacent lens elements of the photography optical system when corresponding to the infinite object distance is ATLmax, and the following conditions are satisfied:
• −15.00<MIN (fL/fi)<−2.80, wherein i is a positive integer, and 1≤i≤a total number of lens elements of the photography optical system;
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A photography optical system comprising a plurality of lens elements, a total number of the plurality of lens elements being eight to nine, the plurality of lens elements comprising, in order from an object side to an image side along an optical path, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element, and each lens element of the plurality of lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;

• wherein the first lens element is a lens element closest to the object side among all lens elements of the photography optical system, and there is no additional lens element disposed between the first lens element through the eighth lens element;
• wherein the first lens element has positive refractive power, the object-side surface of the second lens element is convex in a paraxial region thereof, the object-side surface of the third lens element is convex in a paraxial region thereof, the image-side surface of the third lens element is concave in a paraxial region thereof, and the object-side surface of the fourth lens element is convex in a paraxial region thereof;
• wherein the photography optical system further comprises an aperture stop located between the first lens element and the fourth lens element;
• wherein a focal length of the photography optical system when corresponding to an infinite object distance is fL, a focal length of i-th lens element counting from the object side among the photography optical system is fi, a minimum value of fL/fi is MIN (fL/fi), a focal length of the second lens element is f2, a curvature radius of the object-side surface of the third lens element is R5, a curvature radius of the object-side surface of a first lens element counting from the image side among the photography optical system is Rlast2, half of a maximum field of view of the photography optical system when corresponding to the infinite object distance is HFOVL, and the following conditions are satisfied:
• −13.80<MIN (fL/fi)<−3.80, wherein i is a positive integer, and 1≤i≤a total number of lens elements of the photography optical system;
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