At a mere 5 lbs, this lens is ideal for handheld rigs and offers full frame coverage.  It offers superb optical performance with AR coatings that reduce flares and veiling glare for deep, rich blacks and a wide contrast range.  The Extra Low Dispersion (ED) glass reduces chromatic aberrations, critical for digital camera sensors. The 9 leaf iris generates round, out of focus highlights and a pleasing bokeh.