A series of tests with wide angle and telephoto Canon and Sigma lenses, comparing performance on daylight and star targets.

Outdoor Daylight Tests

20mm Wide Angle Test: Sigma 20m f1.8 EX DG, Canon EF-S 10-22mm, Canon EF-S 18-55mm.

Astrophotography Star Tests

Telephoto Test: Canon EF 200mm f2.8L with 1.4x and 2x tele-converters.

Wide Angle Test: Sigma 20mm f1.8 EX DG & Sigma 28mm f1.8 EX DG.

Zoom Lens Test: Canon 28-135mm IS USM (@28mm, 60mm & 135mm).

All exposures were 30 seconds with Canon EOS 10D Digital SLR. Higher f-ratios were balanced with higher ISO settings to keep the exposure and image brightness approximately equal, which is why the higher f-ratio images appear noisier.