The Pentax interchangeable lens system provides a complete line of high-quality lenses to satisfy your every creative need. Offering a wide range of focal lengths, functions and effects for different formats, Pentax lenses are designed to maximize each camera's capabilities.This model provides manual diaphragm (inner Bayonet Mount). Filter Size is 82mm (Threaded & Bayonet) with gelatin filter clip at rear. Lens Rotation is 360 degrees; Click-Stops at 30 degrees intervals.