Sigma 17-70mm f/2.8-4.5 DC IF Macro Lens
The Sigma 17-70 is my primary walk-about lens. It is on my camera when stored in the bag and looking at the photos I took by far my primary lens I shoot with.
I considered some Canon alternatives before deciding for the Sigma but the extra cost for a Canon was no justified; at least for me.
It is a decently fast lens with a maximum aperture of 2.8 which naturally can only be used around 17-20 mm.
The autofocus motor is quiet and fast.
One negative item to mention is, when the lens hood is on at 17 mm you can get some vignetting, which as far as I can tell only happens when one filter is installed but I always have at least one Skylight filter on.
