Lightweight, 5-Stop Image Stabilization and ease of handling are important considerations for photographers working in the field, and Canon’s EF400mm lens is the lightest in its class. Handling features also play an important role, and the incorporated 5-stop image stabilization and focus lock/activate controls, with full time manual available, make this an eminently hand-holdable and versatile lens. Other impressive specs include a nine-bladed diaphragm, a ring-type USM motor and a minimum focusing distance of 2.5 meters. The lens offers full time manual focusing has is constructed with 17 elements in 13 groups with both fluorite and super UD elements, as well as Air Sphere, Super Spectra and fluorine coatings.