Canon EF 17–40mm f/4L USM Ultra-Wide Zoom LensThis ultra-wide angle zoom lens is ideal for capturing mountain vistas, group portraits cityscapes and interiors. Weighing just over a pound, it travels easily, whether you plan to take it on a hike or a trans-Atlantic trip. Experience exceptional color and clarity when you pair this lens with your Canon EOS DSLR camera.
This lens is of superb quality. I was blown away at how silent the AF is, not to mention the excellent width of angle (even for the cropped-sensor camera I use). It comes with a great lens hood and case and costs around the same amount for a comparable EF-S lens (which I would emphasize does NOT work on higher-end, full-frame cameras). If you're like me and you plan on upgrading to a more expensive, likely full frame camera, I would go ahead and invest the extra money in this reasonably affordable Luxury class lens. I would absolutely recommend it to anyone.
What's great about it: Very affordable. Superb quality build - durable, beautiful, silent, intuitive, and delivers excellent quality images.
What's not so great: Best suited for full-framed sensor cameras, but still well worth the investment even if one has a cropped sensor camera.