I have a love-hate relationship with my Sigma 150mm f/2.8 macro lens. It produces stunningly sharp images but the focus is soooooo slow!! I’ve yet to try or read reviews of the new version of this lens so hopefully they have rectified this. Here is an image of a Green-veined White butterfly nectaring from a thistle head.
Green veined White, Pieris napi, Warwickshire, June, 2011.
Canon 1DIV with Sigma 150mm f/2.8 lens, 1/1250sec at f/7.1 at ISO400.