I love this lens. It's VERY fast, very sharp and creats great quality photos. Can be used in low light and still performs very well. It's well made (not plastic like the popular f1.8) but small and light so ideal for carrying around on your camera without looking too invasive. Obviously as a prime lens with no zoom you have to get used to composing your shots a bit more carefully and walking backwards or forwards - but 50mm is a good standard for many photographs. Great for portraits, of course. I found it a bit too telephoto for my cropped sensor (although great for portraits) but a very good walkabout on my 5D or on 35mm, However, I have noticed the AF not working recently. Image quality is as good as an L lens in my opinion, and it is reasonably priced.