We needed a good wide-angle lens for shooting landscapes, interiors and people at a wide angle with the highest quality picture (sharpness, color reproduction, contrast, minimal distortion and no HA). These qualities are only for L lenses. I thought about buying a Canon EF 16-35mm f / 2.8L II USM, but when I started counting the money for the purchase, common sense took over that I DO NOT PARTICULARLY need it for THIS MONEY .)) I looked in the direction of 17-40. A 1mm wide angle difference (16mm vs. 17mm) and a 2.8 vs. 4 aperture doesn't really matter to me at this angle, where basically everything needs to be sharp.