DPreview has a good comparison of 4 zoom lenses opening at f/2.8 for SLR cameras:
- Canon 70-200mm F2.8 L IS USM
- Nikon AF-S VR 70-200mm F2.8 G
- Sigma 70-200mm 1:2.8 EX DG Apo Macro HSM II
- Tamron 70-200mm 1:2.8 Di LD (IF) Macro
Since they are one of the most coveted segment of the SLR lens market, it was worth mentionning despite the absence of some serious participants like the Sony SAL-70200G – 70-200mm f/2.8 G-Series offering (originating back into the days of the great white lenses from Minolta) or the Pentax SMC-FA* 80-200mm f/2.8 [IF] ED.