A photographic lens optical system which includes five lenses sequentially arranged in a direction from an object to an image sensor is disclosed. A first lens may have a positive refractive power and an entrance surface convex toward the object. A second lens may have a negative refractive power and an exit surface concave toward the image sensor. A third lens may have a positive refractive power and a meniscus shape convex toward the image sensor. A fourth lens may have a negative refractive power and a meniscus shape convex toward the image sensor. A fifth lens may have a negative refractive power, and at least one of an entrance surface and an exit surface of the fifth lens may be aspheric. The system may satisfy the formula: | tan θ|/f