Optical Image Stabilization (IS) Canon's optical Image Stabilization provides four stops of effective shutter speed compensation for camera shake, and can detect normal shooting or panning and automatically switch to the optimal IS mode. This means you can shoot in dimmer conditions, capturing images with shutter speeds up to four stops slower than would otherwise be possible. Glass Molded Aspherical Element (GMo) A single Glass Molded (GMo) aspherical lens element achieves high image quality with improved performance in the edges of the lens. Rear Focusing & Ultrasonic Motor (USM) A ring-type USM, high-speed CPU with optimized AF algorithms, and rear-focusing system combine to enable silent and fast autofocusing to help you focus right on the action. Full-Time Manual Focus Override With this lens, you have access to full-time manual focus for manual adjustment even while in AF mode. Micro‐Stepping Drive Aperture The construction of the aperture mechanism uses micro-stepping drive control for quieter operation during each shot. Minimum Focusing Distance: 9.48" This lens has a minimum focusing distance of 9.48" (24 cm). 8x Circular Diaphragm Blades With eight circular blades, the lens' diaphragm delivers very pleasant, soft bokeh background effects.