Featuring the legendary smc Pentax lens and the unique Pentax Sliding Lens system that allows the lens to retract fully when the camera is off lens, the Optio S4i is sleek and compact enough to carry everywhere. With the optional, acrylic waterproof housing that is newly-designed for the Optio S4i, everywhere may well include the exciting world of underwater digital photography! For optimal results, the Optio S4i now features both Marine Picture and Marine Movie modes to capture drama of blue underwater hues.