Canon RF 24-70mm f/2.8L IS USM Lens Poised to be the new workhorse zoom, the Canon RF 24-70mm f/2.8L IS USM is a versatile wide-angle to portrait-length lens characterized by its bright, advanced, and intuitive design. The constant f/2.8 maximum aperture suits working in difficult lighting conditions and also enables greater control over depth of field. The optical design incorporates a series of aspherical and Ultra-Low Dispersion elements, which greatly reduce a variety of aberrations throughout the zoom range in order to produce sharp and clear imagery. An Air Sphere Coating has also been applied to suppress flare and ghosting when working in strong lighting conditions.