Significant weight reductions — with no loss of durability
Absolutely everything on these lenses, from the tripod mount to the optics, was examined and re-designed with the aim of the world’s lightest 300mm and 400mm f/2.8 super-telephoto lenses.
Fast Auto Focus
Light Weight and Durable for Traveling
Extensive use of these advanced metals
reduce the overall weight of the lenses.
The weight reduction of 3 pounds in the new 400mm is an incredible accomplishment; it’s now about the same weight as the current Canon EF 500mm f/4L IS lens — a lens widely used, up to now, by pro motorsports and wildlife photographers because of its relatively light weight and portability.
Strong, Durable Design
The same attention that went into weight reduction was also applied to preserving and where possible enhancing the mechanical strength and durability of these lenses. The tripod collars (included, of course) have a new surface lubricant, for smooth, quick movement from horizontal to vertical (or vice-versa).
Both lenses utilize Canon ring-type USM, High Speed CPU's and optimized Autofocus algorithms for fast Autofocus.
Better Resistance to the Elements
Extensive network of dust- and moisture-
resistant gaskets and seals at the focus ring,
playback-ring, AF-stop buttons, switch panels,
and lens mount mean these lenses are ready
for harsh conditions.