The optical structure of the LEICA SUMMILUX-M 50mm f/1.4 ASPH. consists of eight lens in 5 groups. Glass with anomalous partial dispersion (elements 2/3) was used to ensure correct color rendition. <BR><BR> Lens element 2 is made of a fluorite-type glass while lens element 3 is made from glass originating from the former Leitz glass laboratory. Lens element 4 has an aspherical surface. Lens elements 1, 6 and 7 are made of glass with a very high refractive index to minimize monochromatic aberrations. In all every innovation currently available in lens technology - aspherical lenses, glass with anomalous partial dispersion (APO), glass with a high refraction index and a floating element - has been combined to create a lens that will set new imaging standards. This is the first Leica M lens with a specifically patented 'floating element' used to maintain imaging performance at a very high level even in close-focus ranges down to 0.7m. During focusing, the rearmost optical component (elements 7/8) moves relative to the rest of the optical system and produces brilliant image quality in near focus ranges. To maximize the benefits of the 'floating element' an extremely precise adjusting mechanism has also been utilized that had to fit into the restricted space inside this compact M-lens <BR><BR> The LEICA SUMMILUX-M 50mm f/1.4 ASPH. also offers special features in terms of its handling: The built-in lens hood not only provides protection against stray light and dust, it can also be locked in the extended position to guard against accidental retracting. In addition to the familiar knurled ring, the lens is equipped with a finger grip that allows easy focusing using one finger. The balanced proportions of the lens also provide comfortable usage for longer periods of time. <BR><BR>Specifications Maximum Magnification - 1 - 11.3 Filter Size - E 46 Dimensions (Length x Diameter) - Aprrox 2' x 2 Weight - 10.5