Mobility and operability of new-generation L-series lenses have been greatly improved, thanks largely to highly sophisticated mechanical design and manufacturing technologies. To meet the challenge of satisfying the demand for more compact, rigid, durable designs, given the limitations of cylindrical lens body shapes, the creators of L-series lenses reexamined basic lens structure and materials, and established optimal assembly processes for each lens in the lineup. As a result, each of them features outstanding feel of operation and ease of handling.
Among lenses with wide zoom range, push/pull type zoom lenses are extra-fast at changing focal distance while rotation-type zoom lenses have very easy focus control and stop precisely at the focusing point being aimed at. The EF100-400mm f/4.5-5.6L IS II USM lens features a rotation-type zooming mechanism. The zoom ring operates smoothly from its wide end to telephoto end, and easily stops zooming and fine-tuning of zoom. Moreover, this lens's zoom ring torque adjustment mechanism allows you to enjoy operation that feels excellent whenever you compose a picture. Also, the focus ring is designed meticulously to incorporate a smooth turning mechanism and high-precision stop control.
Technological innovation provides new solutions to the challenge of designing lenses that maintain balance among factors, including optical characteristics, rigidity, durability, and mobility, that seem to be mutually incompatible at times. New-generation super-telephoto L-series lenses are significantly lighter and more compact, yet deliver images of assuredly high quality. Constant development leads to such advances as lightweight, yet highly reinforced magnesium alloy and intensity simulations that optimize lens mechanisms.