Tamron SP AF 17-50MM F/2.8 XR Di II LD Aspherical (IF) Lens with hood for Canon - International Version (No Warranty) Maximum Aperture: F/2.8, Minimum Aperture: F/32, 13/16 Lens Construction, Weight: 430g, Minimum Focusing Distance: 0.27m, 7 Circular Apertures The SP AF17-50mm F/2.8 is a lightweight, compact, fast standard zoom lens designed exclusively for digital SLR cameras, expanding the product concept of the popular SP AF28-75mm F/2.8 zoom lens.