Optical imaging system and camera module including the same

A camera module comprising:

• a housing;
• a lens module disposed in the housing and comprising a lens barrel and a plurality of lenses disposed in the lens barrel;
• and
• a first reflective member disposed in the housing and comprising a reflective surface configured to receive incident light from an object and reflect the incident light toward an object side of the lens module,
• wherein the plurality of lenses comprise a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially disposed in ascending numerical order along an optical axis from the object side of the lens barrel toward an imaging plane of an image sensor,
• the first lens has a positive refractive power, a non-circular shape when the first lens is viewed in a direction of the optical axis, a first axis intersecting the optical axis and perpendicular the optical axis, and a second axis intersecting the optical axis and perpendicular to the optical axis and the first axis, a length of the first axis being greater than a length of the second axis, and
• the following conditional expressions are satisfied:
• 3.5≤TTL/IMG HT
• |f1+f2|<2.0 mm
• 0.7≤L1S1es/L1S1el<1.0
• where TTL is a distance along the optical axis from an object-side surface of the first lens to the imaging plane of the image sensor, IMG HT is one-half of a diagonal length of the imaging plane of the image sensor, f1 is a focal length of the first lens, f2 is a focal length of the second lens, L1S1el is a maximum effective radius of the object-side surface of the first lens when the first lens is viewed in the direction of the optical axis, and L1S1es is a minimum effective radius of the object-side surface of the first lens when the first lens is viewed in the direction of the optical axis.