I'm about to pull the trigger on a lens to cover the wide end of the focal range. At present, my widest lens is a 20mm f2.8 prime (32mm on my 1.6x crop Canon 60D), and I need to go wider for some interiors, crowd shots, and added drama. For crowd work, something that zooms for fast framing would be a welcome change from my usual primes. For fast work, autofocus is a must (I realize very wide lenses can be often be manually focused from very close to infinity and "taped down"). The lens must be full-frame compatible, since I don't want to leave it in the dust when/if I go FF. I'm casting the widest possible net to try and figure out the best fit. As I see it, I have three options. They're listed below according to how well I think they fit.
- Sigma 12-24mm f4.5-5.6 EX DG HSM ($850): Current leader. Good focal range (19-38mm at 1.6x), excellent price. Only concern is the relatively tight aperture. If used in low light at ISO3200, f4.5 probably means I'll be shooting at 1/20-1/50sec. Manageable, but borderline. Image quality based on comparison charts from The Digital Picture looks good, but less than Canon 16-35mm f2.8L II. Borrowed one in Germany for a few minutes and enjoyed mucking about with it.
- Canon EF-S 10-22mm f3.5-4.5 ($820): Essentially the same focal range as the Sigma, and slightly wider, but without FF compatibility. Would probably replace this lens after going FF, so if I want to avoid spending money twice, it's not the right choice.
- Canon EF 8-15mm f4L ($1,300): Not sure if I need to go this wide. Seems like 180deg (on full frame) is an extreme, and rarely useful, field of view, and that 15mm might still be too wide for my applications. To my mind, this lens could be easily replaced with a Samyang 8mm fisheye.
- Canon EF 16-35mm f2.8L II ($1,460): Focal range probably too long for my application. Expensive, but wide. Not sure going to f2.8 is worth double the cost of the Sigma.
Did I miss anything? Any comments from users of these lenses? Pitfalls? Technical input? Keen to hear all opinions before I ante up for my most expensive lens yet.