<p>The present invention relates to a high resolution optical system. The optical system of the present invention includes, sequentially from an object side, a first lens having a positive refractive power and an object-side surface convex toward the object side; a second lens having a negative refractive power and an upwardly concave upper surface; a third lens having a positive refractive power; at fourth lens having a negative refractive power; a fifth lens having a positive refractive power and an upwardly convex upper surface; and a six lens having a negative refractive power and an upwardly concave upper surface.</p>