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

Great lens for your money. I took a new one for 23 thousand. He draws very beautifully. Not always sharp at the maximum hole, but does an excellent job with apertures from 5.6. You need to be careful when shooting paintings, mirrors, posters - at a wide angle, sometimes the lines are strongly distorted. At 40 (64) mm, not bad as a moderate portrait. Has some pros Universal FR on the crop. Sharp enough. Working hole 5.6-8. Great for daytime reporting. Moderate landscape painter. Normally holds backlight. All image distortions at a wide angle are easily corrected in FS. Its cons: Focus is not always accurate. Open back "hole" - the mechanism is visible.