Excellent optical performance with consistent f/2.8 maximum aperture throughout the zoom range of 24–105mm Supports either of two optional Canon Power Zoom Adapters, enabling smooth, high- precision zoom control during movie shooting Eleven aperture blades, for super-smooth out-of-focus foregrounds and backgrounds. Iris ring (aperture control) for extremely precise lens aperture control adjustment and degree of bokeh with clickless, smooth operation. Close-focusing to under 1.5 feet (0.45m) at all focal lengths; maximum magnification 0.29x at the 105mm zoom setting