The first thing that strikes you about the Sigma 15-30 is it’s size. This is a big lens - 182mm long, 87mm across and weighing in at 620g. It has a huge curved, vulnerable front element, and although Sigma do provide a very good front cover and a tiny rear mounted filter holder - for gels - filters are not a realistic option with the Sigma 15-30.
Performance is very good - provided you keep to about f8 or better, but even then the lens doesn’t have the real bite of the newer digital only Canon 10-22mm EF-S. Images shot at full aperture look fairly soft but do have lots of detail. Results overall are very good, but with the Fuji S2 even more sharpening than usual was required. The Sigma 15-30mm is part of Sigma’s EX DG pro lens series which although designed for digital, will work with film or full frame digital camera bodies. Distortion levels are reasonable with some barrel distortion at 15mm but levels are lower than many standard zooms.
Overall a good rather than great lens. If you need a superwide zoom for film as well as digital it’s a good option, but the Nikon 12-24 DX and the Canon 10-22 EF-S are both sharper and have a more useful range for APS-C size sensor DSLR’s.