I will use it for nightscapes. Due to the 500 or 600 rule (500 divided into the longest length of your lens yields sharp stars without trails) the shorter the better! It may cost me a fortune as an enthusiast amateur. But it will be a great lens, one you buy once in a lifetime. Thought about the Sigma 12-24 4.5-5.6 first, but I held myself back and now I am glad I did. 16-35 seemed a bit long according to the above mentioned technique. So, can't wait to add it to my lens line up and do night sky at 14mm even wide open and ISO 6400, 8000 or even 12800 on my 5Diii! Won't buy it in the first hour once it hits the shelf, as saving up for it is almost as much as great! Meanwhile, the 28 2.8 will do.