While visiting my daughters in east Texas I just had to visit Competitive Camera in Dallas and acquired one of Sigmas new offerings. This lens fills a void in my line up that I never did fill in my 35mm film camera line up. I wasn't looking for a fisheye lens but an extreme W/A and this lens fills that niche very capably. The petal style hood is a permanent part of the lens with an adapter "ring" that slides over the hood and the lens cap attaches to this ring. With a F stop of 4.5-5.6 I feel it is fast enough for my needs with the T2i's iso range. If you are looking for a high quality W/A lens I suggest you check this lens out.