Sigma Lenses
This section comprises of the Sigma lenses that I have personally used at some point in time. My rating is based on the summary of factors. Such as quality of the pictures in terms of sharpness and contrast, usability, distortions and what it has been designed to do, i.e. macro.
ASPHERICALFor better performance
DGLens coating is optimised to be used on digital SLRs
EXExcellence (presumably better quality lenses)
HSMHuperSonic motor for faster focusing
Wide angle
10-20mm F4-5.6 DG HSMoftenExcellentWell built. Great for landscapes and tight spots. Performs well. Good colour reproduction.
17-35mm F2.8-4 EXrarelyVery goodWell built. Works properly on film and digital SLRs. Images are softer at large apertures than by its Nikon counterpart. Color reproduction is very good.
24mm F1.8 EX DG ASPHERICAL MACROrarelyVery goodPro-built. Fast auto-focus. Produces good sharpness only when it reaches f5.6 aperture. That defeats the purpose of a faster lens. A 24mm f2.8 Nikon would probably be a better deal.