Photographing optical lens system, image capturing unit and electronic device

A photographing optical lens system comprising seven lens elements, the seven lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element;

• each of the seven lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side;
• wherein the object-side surface of the first lens element is convex in a paraxial region thereof, the seventh lens element has negative refractive power, and the object-side surface of the seventh lens element is concave in a paraxial region thereof;
• wherein at least one of all lens surfaces of the seven lens elements is aspheric and has at least one inflection point, an axial distance between the object-side surface of the first lens element and an image surface is TL, a maximum image height of the photographing optical lens system is ImgH, a focal length of the photographing optical lens system is f, a focal length of the second lens element is f2, an entrance pupil diameter of the photographing optical lens system is EPD, a curvature radius of the image-side surface of the seventh lens element is R14, a sum of central thicknesses of all lens elements of the photographing optical lens system is ΣCT, a central thickness of the seventh lens element is CT7, and the following conditions are satisfied:
• TL/ImgH<1.75;
• f/EPD≤1.70;
• f/R14≤0;
• f/f2<0.70;
• and
• 1.00<ΣCT/CT7<20.0.