Review on Ultra Wide Angle Zoom Lens for SLR Cameras - Canon EF 17-40mm f/4L USM by Ayden Loh ᠌

I shoot on a Canon 400D with software sharpening (sharpening) turned off. And everything is 100% sharp at the maximum resolution of 10MP. The abomination of digital photography compared to film is mainly due to the aggressive use of software sharpening. But not every lens allows you to turn it off. And with this you can. The photo is almost like a scanned film. With crop of 1.6, there is practically no drop in sharpness at the edges, since sharpness at the edges begins to fall just in that part of the field of view that does not work on crop. Chromatic aberration is only visible at 17mm in some areas of the short edges of the image and in the corners. And this is if you shoot trees with small branches at full resolution of 10MP against the background of the sky so that branches one, two or three pixels wide are present and take a very good look at the enlarged image. Yes, the sharpness of the lens is such that, with software sharpness turned off, it allows you to clearly see branches 1-2 pixels thick on a tree. If you shoot a landscape so that the sun enters the frame, then there will be no glare and bunnies, the image will only be cloudier due to diffuse reflection of light from the sun. For a full format with a resolution significantly more than 12MP, I do not recommend it. At 12MP, the full format has larger pixels, so the described distortions will be only slightly more noticeable than on the crop.