imho, above = no. 3: the Samyang, Rokinon, Bower 14mm f2.8. fun lens. easy to handle MF just use hyper-focus method.
aside from Canon's new budget buster 11-24mm, there's a paucity of great Canon ultrawides. zoom or prime.
I've used the ef 17-40mm f4L along with a Rokinon 14 & a Samyang 8. I also have a shelf of other canon primes, mostly wide angle: 20, 24, 28, 35, 40 & I just added the new ef-s 24 pancake stm.
again, nothing special about the 17-40 - except it's decent, it works, and I'd be hard pressed - today - to suggest a better quality/value offering. optically, the 16-35mm IS f4 is a preference - but one that I - so far - have found hard to justify in terms of real added value for funds expended.
perhaps others have more experience with this one...
good luck.



