Sigma 50mm f/2.8 (D) EX DG Macro Autofocus Lens for Sony Alpha & Minolta Maxxum Series Type: Macro Lens Focus Type: Auto Focus Diameter: 55mm Compatibility: For Sony Features: Super Multi Coating reduces flare and ghosting that tends to occur when using digital SLR cameras. Optimized optical design for digital SLR cameras. Macro lenses require a high imaging performance for photographing objects with digital SLR cameras. Floating Focusing System Standard 50mm lens for digital SLR cameras. Minimum aperture of F45 A screw-in lens hood Lens Construction: 10 Elements in 9 Groups Angle of View: 46.8 degrees Number of Diaphragm Blades: 7 Blades Minimum Aperture: F45 Minimum Focusing Distance: 18.9cm/7.4 in. Maximum Magnification: 1:1 Filter Size: Diameter 55mm Dimensions: Diameter 71.4mm x Length 66.5mm / 2.8" x 2.6" Weight: 320g / 11.3 oz.