Anyone know which Ultra Wide Lens is best out of this group:
Basically, of all the Crop Sensor Ultrawides, these are the 3 that I culled from the list first. The 3 to choose from are the Sigma 8-16, Tokina 11-16, Canon 10-22.
Sure, they're more expensive than the first 3 New, but second-hand you can get the Sigma/Tokina for $450-500, the Canon for $600.
Choose between them for: Sigma: slow, outdoors, no filters, widest, landscapes. Tokina: fastest, least zoom range, better indoors, or handholdable in lower light (bit more CA than the rest, apparently mk2 just announced will be better). Canon: halfway between the two, holds up value a bit better (but any of the three, if you buy 2nd hand you can sell later for not much profit).
If your budget really really doesn't stretch that far, then:
Tokina 12-24 is fairly old and got replaced by the 11-16, i don't know much about it.
Tamron just avoid, it's the cheapest for a reason.
Sigma 10-20 i reckon the f/4-5.6 version is a bit sharper than the f/3.5 version.
Or if you don't want absolute widest now (but will if/when you go FF later), the Sigma 12-24 are a good upgrade path. mk1 for almost completely rectilinear the whole way, mk2 is sharper.
Still, my vote lies on the second-hand Sigma 8-16 or Tokina 11-16 (mk2 if you can get it, but it'll be more expensive new because there will be no second-hands for a year).