The Panasonic 25mm f/1.4 Leica D Summilux Lens is an interchangeable bright standard lens, developed by Leica exclusively for digital SLR cameras, and follows the Four Thirds Standard. This means that the lens is also interchangeable with other manufacturers that use this format. With an ultra-bright maximum aperture of f/1.4 and a focal length that comes closest to what the human eye sees (50mm in 35mm format terms), this lens is ideal as a general purpose lens for all shooting situations. Aspherical Lenses Leica's optical design, including its one aspherical lens element, helps the lens to achieve its extremely high optical performance standard. Multi-Coated Multi-coated lens elements reduce ghosting and flare to an absolute minimum, enabling the lens to deliver an optical performance that meets Leica's lofty standards. Aperture Ring The included aperture ring, in addition to the focus ring, provides users with the kind of easy, pleasant, intuitive operation offered by familiar film cameras. Circular Aperture 7-blade circular aperture diaphragm produces brilliant out-of-focus characteristics. Four Thirds Standard Lens Mount Use of the Four Thirds Standard means that this lens can also be used with other manufacturers that have adopted this digital camera standard.