No i'm broke, invested in the best lenses (all second hand) and just saved for a 17-40 (or other likewise priced UWA) or my wife will trow me out 
bamatt wrote in post #14663451
Based on your gear list, I assume you could afford a 24mm L II?
Yes I also thought of a prime, the 24 1.4L is not wide enough (not really UWA), the 20 2.8 seems a better range but it gets only 7.5/10 on fredmiranda which is a representative website http://www.fredmiranda.com …ct=28&sort=7&cat=2&page=1
Canon has no other option for a fast wide affordable prime pity enough.
Therefore my only options were 20-35 2.8L (12y old) or 17-40 f4L
I found a reasonable cheap 17-40 for 500 USD, mostly they ask 566 USD second hand over here.
===> If you have suggestions for a third party brand UWA prime (between 16 and 20mm), let me know 
Sigma 14 2.8 seems too wide and Sigma 20mm f/1.8 EX DG hasn't got a good score either.
The Tamron SP AF14MM F/2.8 Aspherical has 8.8/10 and Tokina AT-X 17 AF PRO 17mm f/3.5 has highest 9.2/10 (but only 13 reviews).
Tokina seems best at the moment... don't you find 14mm too wide on Fullframe, for buildings inside for example?
Logicus wrote in post #14663708
I'd suppose that you'd get better bang-for-your-buck sharpness with a prime if that's what you're seeking. Every lens has a different character to it. I have the Sigma 12-24mm and though it's well known for being not particularly sharp at the corners, I've found that I can get very sharp corners at about f/20, but you have to keep in mind that this is dependant on your composition. If youre in a smallish area and are photographing something far away, then you would have things that are just a foot or so in front of you while also having the center (at which you're probably locking focus) 50 feet away. Kinda hard to get that much depth into focus.