An optical system includes an object side lens unit arranged closest to an object, immobilized in focusing, and having a positive refractive power, an image plane side lens unit arranged closest to an image plane and having a negative refractive power, and a first focus lens unit and a second focus lens unit which are arranged between the object side lens unit and the image plane side lens unit and are moved in focusing. The object side lens unit consists of a first partial unit having the negative refractive power, a second partial unit having the positive refractive power, a third partial unit having the positive or the negative refractive power which are arranged in order from an object side to an image plane side. The second partial unit is moved in a direction including a component in a perpendicular direction to an optical axis in image blur correction.

A four-piece optical image capturing system is disclosed. In order from an object side to an image side, the optical image capturing system along the optical axis includes a first lens with positive refractive power; a second lens with refractive power; a third lens with refractive power; and a fourth lens with refractive power; and at least one of the image-side surface and object-side surface of each of the four lenses are aspheric. The optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

A four-piece optical image capturing system is disclosed. In order from an object side to an image side, the optical image capturing system along the optical axis includes a first lens with positive refractive power; a second lens with refractive power; a third lens with refractive power; and a fourth lens with refractive power; and at least one of the image-side surface and object-side surface of each of the four lenses are aspheric. The optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

An optical imaging system includes four lens elements which are, in order from an object side to an image side: a first lens element, a second lens element, a third lens element and a fourth lens element. Each of the four lens elements of the optical imaging system has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The object-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex shape in an off-axis region thereof. The object-side surface of the first lens element is aspheric. The image-side surface of the fourth lens element is concave in a paraxial region thereof. The optical imaging system has a total of four lens elements.

An optical imaging system includes four lens elements which are, in order from an object side to an image side: a first lens element, a second lens element, a third lens element and a fourth lens element. Each of the four lens elements of the optical imaging system has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The object-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex shape in an off-axis region thereof. The object-side surface of the first lens element is aspheric. The image-side surface of the fourth lens element is concave in a paraxial region thereof. The optical imaging system has a total of four lens elements.

An electronic device includes an optical lens assembly. The optical lens assembly includes four lens elements which are, in order from an outer side to an inner side: a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element has negative refractive power. An outer-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex critical point in an off-axis region thereof. The third lens element has positive refractive power. The fourth lens element has an inner-side surface being convex in a paraxial region thereof and having at least one concave critical point in an off-axis region thereof. The optical lens assembly has a total of four lens elements.

An electronic device includes an optical lens assembly. The optical lens assembly includes four lens elements which are, in order from an outer side to an inner side: a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element has negative refractive power. An outer-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex critical point in an off-axis region thereof. The third lens element has positive refractive power. The fourth lens element has an inner-side surface being convex in a paraxial region thereof and having at least one concave critical point in an off-axis region thereof. The optical lens assembly has a total of four lens elements.

Provided are an imaging lens system, a camera module and an electronic device. The imaging lens system, from an object side to an imaging plane, sequentially includes: a first lens with a negative focal power, a second lens with a positive focal power, a third lens with a positive focal power and a fourth lens with a negative focal power. An object side surface of the first lens includes a paraxial region and a peripheral region. In the object side surface of the first lens, at least one inflection point is defined between the paraxial region and the peripheral region, and the paraxial region is concave relative to the at least one inflection point. An image side surface of the third lens is convex. A paraxial region of an image side surface of the fourth lens is concave.

Provided are an imaging lens system, a camera module and an electronic device. The imaging lens system, from an object side to an imaging plane, sequentially includes: a first lens with a negative focal power, a second lens with a positive focal power, a third lens with a positive focal power and a fourth lens with a negative focal power. An object side surface of the first lens includes a paraxial region and a peripheral region. In the object side surface of the first lens, at least one inflection point is defined between the paraxial region and the peripheral region, and the paraxial region is concave relative to the at least one inflection point. An image side surface of the third lens is convex. A paraxial region of an image side surface of the fourth lens is concave.

An optical imaging system includes four lens elements which are, in order from an object side to an image side: a first lens element, a second lens element, a third lens element and a fourth lens element. Each of the four lens elements of the optical imaging system has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The object-side surface of the first lens element is concave in a paraxial region thereof and has at least one convex shape in an off-axis region thereof. The object-side surface of the first lens element is aspheric. The image-side surface of the fourth lens element is concave in a paraxial region thereof. The optical imaging system has a total of four lens elements.