This lens has a macro focusing capability with fast F1.8 maximum aperture, which is ideal for Digital SLR cameras. Macro capability: This lens is capable of Macro photography, with minimum shooting distance of 20cm (reproduction ratio 1 : 2.9) and angle of view is 75.4. You can take picture not only the subject but also the surrounding scenery. Large front element and Super wide-angle: The lens has an advanced optical construction, in order to obtain adequate peripheral brightness with open aperture. Also, the iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus images in the foreground and background. Handling: The lens incorporates a Dual-Focus (DF) mechanism. It is easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. Also, this also allows the use of a Petal-type Hood and the easy use of a polarizing filter. Aspherical lens: It incorporates a floating focus system and uses two aspherical lens elements for minimizing distortion, aberration and astigmatism. Specifications - Lens Construction - 10 Elements in 9 Groups Angle of View - 75.4 degrees Number of Diaphragm Blades - 9 Blades Minimum Aperture - F22 Minimum Focusing Distance - 20cm Maximum Magnification - 1:2.9 Filter Size - 77mm Dimensions - Diameter 83.6mm X Length 82.5mm Weight - 500g