The 11-18mm f/4.5-5.6 DT Wide Angle Zoom Lens from Sony is a DT-series Alpha lens that has been optimized for cropped image sensors, and as a result it is not recommended for use with larger full-frame cameras. Its 11-18mm focal length is the 35mm equivalent of a 16.5-27mm lens. It is constructed of 15 elements in 12 groups - three of them being aspherical glass elements, with additional Extra-low Dispersion (ED) glass elements - which all help to deliver sharp, clear photos throughout the zoom range. It has a minimum focusing distance of 9.8" and a front-end filter diameter of 77mm.
APS-C 35mm Equivalent: 16.5-27mm
This wide 11-18mm lens has a 1.6x zoom factor, but its viewing angle becomes the 35mm equivalent of a 16.5-27mm lens when attached to the cropped APS-C cameras it was designed for.
Optimized For APS-C Size / DT-Format Alpha & Minolta DSLRs
Intended for smaller, cropped Sony Alpha cameras, DT lenses employ an optical system that is specifically designed for digital cameras which incorporate an APS-C size image sensor.
Extra-Low Dispersion (ED) Elements
To reduce chromatic aberrations, most noticeable when zoomed all the way in, the extra-low dispersion glass corrects for certain wavelengths of light - producing sharper images with truer colors.
3x Aspherical Glass Lens Elements
These precision lens elements correct distortion for sharper, more visually accurate images across the entire zoom range of the lens.
Internal Focusing System
Internal lens elements move, so the overall length does not change, creating a lens that focuses more quickly and doesn't change balance.
7x Circular Aperture Blades
Circular aperture blades produce smooth, rounded bokeh background effects when capturing spot-light sources in your pictures. Because the aperture blades form a near circle at the wide openings used for low-light shots, spot-light sources have a pleasing circular defocused effect.
Filter Diameter: 77mm
The 77mm front filter thread does not rotate, allowing rotating polarizing filters to be used.