Sigma has announced its 18-35mm F1.8 DC HSM Art lens for APS-C DSLRs – the world’s first constant F1.8 zoom -will be available from July at a cost of around $ 799. The lens covers a 27-52.5mm equivalent range, and will be available in Canon, Nikon and Sigma mounts. The lens will offer the depth-of-field equivalent of a constant F2.7 on full-frame, and allow the use of lower ISO settings in low light, which may under-cut the need for some photographers to change formats.
News: Digital Photography Review (dpreview.com)