A ruggedly constructed, large-aperture, full-frame, image-stabilized, 1:1 close-up lens, this medium telephoto prime ($970, street) converts up to about 150mm on Sigma’s SD1, as well as on most DSLR cameras with APS-C sensors.Its attractions include a nonrotating barrel suitable for lens-mounted macro ringlights; super-low dispersion and high- refractive index elements that correct for color fringing; and a hypersonic focu-sing motor with manual-focus override. It accepts Sigma APO teleconverters.