A worthy successor to the popular Canon EF 300mm f/2.8 IS, the all-new Canon EF 300mm f/2.8 IS II USM super telephoto lens is lightweight, weighing approximately 13% less than its predecessor, yet offers faster operation, improved image stabilization and superior optics. Incorporating Fluorite elements for improved image quality and reduced chromatic aberration plus a number of advanced coatings to minimize ghosting, flaring, and with a newly developed Fluorine coating that keeps soiling, smears and fingerprints to a minimum, this lens is ready to deliver spectacular images in an instant. With a third Image Stabilization mode (Mode 3) that activates IS only when the shutter button is fully pressed, and giving the equivalent effect of a shutter speed four stops faster, the EF 300mm f/2.8 IS II USM allows for easy panning and is ideally positioned for professional action photography. It also features a new security slot for wire-type security locks.
This is the magnifying factor of a lens. Macro lenses will often be described by their “magnification factor”. A lens with a 1:1 magnification factor produces a projected image on the sensor which is the same as the subject.
The individual pieces of glass that form the overall optical construction. Most lenses have between four and eleven elements to bend the light rays to ensure a perfectly formed image appears on the light sensitive surface, such as a film or CCD. The elements are arranged in groups and may be seen in specification sheets as, for example, 6 elements in 4 groups. That configuration may have two single elements and the other four grouped in pairs.