Compact, high performance L-series super-telephoto zoom makes it ideal for sports and wildlife photography Rotation-type zoom ring allows for more precise composition and excellent balance when handholding.Rounded 9-Blade Diaphragm Improved zoom torque adjustment ring allows easy setting of zoom tension, Focal Length & Maximum Aperture:100-400 millimeter 1:4.5-5.6, Closest Focusing Distance-3.2 feet; 0.98 meter New Air Sphere Coating (ASC) helps to significantly reduce backlit flaring and ghosting, Highly resistant to dust and water, and amazing durability enabling shooting even in harsh conditions