With an F3.5 aperture throughout the entire zoom range, the 10-20mm F3.5 is perfect for low light photography. Sigma wide angle lenses accentuate the relationship of subjects within a photo and thus become an important creative tool for photographers. Designed for APS-C DSLRs, this fast fixed aperture lens makes photography easier for the photographer who wishes to precisely control their depth of field and also for working with non TTL Flash systems. Super Multi-layer coating reduces flare and ghosting, four aspherical lenses provide correction for distortion and an inner focusing system eliminates front lens rotation, making it suitable for use of polarizing filters. Perfect for shooting landscape photography, architecture photography, interior photography, photojournalism, wedding photography, group/event photography and more.