17-40mm F/4 L or 16/35mm F/2.8 L I

[killswitch]

I'm in a similar predicament. coming from the 10-22 on a crop, I really liked 10mm. My main concern isn't the extra stop of light as I will probably be shooting at f/5.6 to f/8 anyway. I've read that in UWA lenses, 1 mm makes a big difference. Is the difference between 16mm and 17mm significant?

Canon has a decent lens comparison tool so you can see the difference in focal lengths. Give it a try, hope it helps. http://canonlenses.ca/Get-a-wider-perspective

I just recently went through the same decision process as well. Bought a 5d3 about a week ago and was trying to decide on what UWA to get to replace my 10-22. Decided on the 16-35 f2.8 II. So far I couldn't be happier with my choice.

OMG, this is awesome. I am facing the same dilemma as AudioGlenn, this comparison tool is what I have had been looking for to confirm the 1mm difference between 17-40 and the 16-35!!! Thank you so much for sharing!!!