I finally go with a 16-35mm f/2.8 L II lens instead of primes after some careful inspection and refined requirement. Firstly, it comes with my most favorite focal length ranges, that is a compromised solution - versatile and high speed for landscape as well as event work in low light environment.
Secondly, 16-35mm f/2.8 L II is a new design lens optimized for latest Canon FF body, it has consistent performance across apertures. In fact, Canon made this lens to work at wide focal length and wide open aperture, I am surprised by its output at 16mm f/2.8. Lastly, 16-35mm f/2.8 L II has very nice blur background effect that worths its price for some creative and lower available light work.
I managed to trial run it with my Canon 5D for some indoor shots, well, this is where it worths the price double over the 17-40/4. All samples are wide open at f/2.8. See more samples at Canon EOS 5D - Dark Angel in Digital Photography.
First attempt to do barbecued pork for dinner.

It looks quite nice to serve ….

And there is a mess to be clean up ….



