Professional super-telephoto prime lens for Canon EF mount, known for its fast aperture and image stabilization.
The Canon EF 400mm f/2.8L IS III USM is the current flagship version of Canon's most iconic super-telephoto prime, introducing a significant weight reduction over previous versions (approximately 2840g vs 3850g for IS II) through extensive use of magnesium alloy and fluorite elements. IS III denotes the third generation Image Stabilisation system, rated at 4 stops.
400mm focal length, f/2.8 maximum aperture, fluorite and UD elements, 4-stop IS III, Ring USM AF drive, L-series weather sealing, Canon EF mount, fluorine front element coating, approximately 2840g.
The IS III's weight reduction was a landmark improvement — at 400mm f/2.8, even a kilogram reduction is significant for hand-held shooting endurance. The 4-stop IS enables much longer hand-held use than previous versions. Used with 1.4× and 2× teleconverters, it covers 560mm f/4 and 800mm f/5.6 respectively. A reference lens for professional sports and wildlife photography.
Test IS function and all IS modes. Verify AF accuracy and tracking speed on moving subjects. Inspect front fluorine element for any damage. Confirm EF mount contacts are clean. Check the extender/teleconverter compatibility. At this price tier, service history and provenance are critical considerations.