The RF 15-35mm f/2.8L IS USM from Canon is also characterized by its bright f/2.8 constant maximum aperture. This bright design enables working in available light conditions and also affords greater control over the depth of field. An Air-Sphere coating has also been applied to reduce flare and ghosting for improved contrast and color fidelity when working in bright conditions. A unique Control Ring is also integrated into the lens design for intuitive control over exposure settings from the lens itself.