became the first Canon lens with a Hybrid Image Stabilizer. In addition to correcting angular movement, Hybrid IS also corrects for shift movement. In 2011, with the release of the 300mm 2.8L IS II and 400mm 2.8L IS II, IS Mode 3 was added. This mode is similar to Mode 2, except that stabilization is applied only when the shutter is released. Some newer lenses include an Image Stabilizer which can automatically detect whether the user is panning and respond accordingly, and therefore these lenses do not have an IS mode switch. All EF lenses that support IS have the words "Image Stabilizer" written on the lens. On some of Canon's larger telephoto lenses, the words "Image Stabilizer" are etched onto a metal plate affixed to the lens. Diffractive optics Diffractive optics (DO) are special lens elements that are used in some lenses. DO lenses are usually smaller and lighter and are better at handling chromatic aberration, compared to conventional lenses of similar focal length and aperture value. They are more expensive to make. Only the EF 400 mm 4 DO IS USM, its updated Mark II version, and the EF 70–300 mm 4.5–5.6 DO IS USM contain DO elements. DO lenses have a green ring on the barrel. L-series lenses Top range Canon EF lenses are designated "L-series", or "Luxury" lenses. L series lenses are compatible with the full range of EF or EF-S mounts and, as they are aimed at the high-end user, most also include environmental or weather sealing and a constant maximum aperture. All L lenses are supplied complete with a hood and a pouch or case, which are not generally included with non-L lenses. Distinctive visual cues include a red ring around the lens and an off-white colour on longer-focal-length models. The latter also helps to reflect light and reduce heat absorption and subsequent internal expansion of lens components that can affect the image quality of long focal length lenses. All L lenses include at least one fluorite, ultra-low-dispersion glass element, super ultra-low-dispersion glass element, and/or certain types of aspherical elements. (Note that a number of non-L lenses also use aspherical element, and at least one non-L lens has a Super UD element) Most L lenses feature an ultrasonic motor (USM) for focusing. Timeline of innovations In 1987 Canon was the first to use USM (Ultra Sonic Motor) with the Canon EF 300mm f/2.8L USM.