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 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.An Image Stabilizer also compensates for up to five stops of camera shake to help produce sharper handheld shots in difficult lighting conditionsA unique Control Ring is also integrated into the lens design for intuitive control over exposure settings from the lens itself.  This focusing system also affords full-time manual focus control when working in the one-shot AF mode.