During the summer, my career as a photographer blossomed. I'm seventeen years old, shot two magazine covers, sold some very large (over six feet) prints, had one of my photos go viral and photographed a wedding. In all I earned a couple of grand but most of that I would like to put into savings for during and after college. I shoot on a Canon 5D MKII and do a lot of landscapes. For my landscape lens, I use a 17-40mm F/4 L and sometimes my 50mm, 105mm and 200mm for high quality panoramas. I haven't been using my 17-40 very much do to the fact it is extremely soft and has huge amounts of CA in the corners. Below I will include a shot from the middle edge at F/8. I have been considering upgrading to a new lens as most of my work is landscapes and my 17-40 is most definitely my weakest lens with a slow aperture and soft corners even stopped way down. I need a lens that is sharp through out the image stopped down, I'm fine with soft edges wide open, I'm not shooting landscapes at F/4 and would not be shooting them at F/2.8. I would like there to be as little amount of coma as possible so that I could use the lens for astrophotography instead of my 50mm 1.8.
Canon only really has the 16-35mm which is very expensive and sounds like it is not much sharper then the 17-40mm in the corners. Tokina's 16-28 sounds like a great lens for a great price but i would like to hear what others think of it. I have heard that Tokina doesn't have the best quality control. http://petapixel.com/2013/07/07/4th-of-july-fireworks-captured-together-with-lightning/