The present disclosure provides a photographic optical system. The photographic optical system includes, from an object side to an image side: a first lens (having a focal length of f1), a second lens (having a focal length of f2), a third lens (having a focal length of f3), a fourth lens (having a focal length of f4), a fifth lens (having a focal length of f5) and a sixth lens (having a focal length of f6) arranged coaxially and satisfying the following relational expressions: 0.8