An optical image capturing system, from an object side to an image side, comprises a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element. The first lens element has a positive refractive power and may have a convex object-side surface. The second through fifth lens elements has a refractive power and the object-side and image-side surfaces of these lens elements are aspheric. The sixth lens element has a negative refractive power and a concave image-side surface. The object-side surface and the image-side surface are aspheric, and at least one of the two surfaces has inflection points. The first through sixth lens elements has a refractive power. When specific conditions are satisfied, the optical image capturing system may has a large aperture value and a better optical path adjusting ability to acquire better imaging quality.