Sigma 17-50/2.8 EX DC OS HSM CANON is ideal for photography professionals and enthusiasts alike because of its Compact And Sleek Design, Bright f/2.8 maximum aperture & 27.2-80 mm equivalent focal length! The lens possesses a bright f/2.8 maximum aperture that allows crisp imagery in difficult lighting conditions. Further, it provides improved control over the depth of field that facilitates subject isolation and enables working with selective focus techniques. Additionally, the constant f/2.8 maximum aperture allows consistent performance even in the full zoom range. Our Take on the Sigma 17-50/2.8 EX DC OS HSM CANON: The design comes with two FLD and three aspherical elements that reduce chromatic and spherical aberrations and limit distortion. Further, the rounded seven-blade diaphragm adds smoothness and results in astounding bokeh quality. The Super Multi-Layer Coating suppresses flare and ghosting and renders higher contrast and color fidelity in strong lighting conditions and harsh climates. In addition, the Hyper Sonic Motor (HSM) outputs quick and quiet autofocus. The AF motor even allows full-time manual focus override. The optical image stabilization helps in maintaining image sharpness in the full zoom range. Although the Standard zoom lens is designed for full-frame Canon EF-mount cameras, it is compatible with APS-C models also. The lens provides 27.2-80mm equivalent focal length in APS-C Camera models. Further, its sleek, compact, and lightweight design makes it perfect for on-the-go or traveling photographers. TOP 10 KEY FEATURES: Lens Construction: 17 Elements in 13 Groups Format Compatibility: APS-C Lens Mount: Canon EF Angle of View: 79.7° to 31.7° Diaphragm Blades: 7 Blades (Rounded diaphragm) Maximum Magnification: 0.2x Minimum Focus Distance: 11" (28cm) Focal Length: 17 to 50mm (35mm Equivalent Focal Length: 27.2 to 80mm) Focus Type: Autofocus Minimum Aperture: f/22 Included in the box: Sigma 17-50/2