Excerpt: First the good news: this is an excellent, sharp, lightweight lens. I chose to add it to fill the gap between the 24-105mm and my prime 300mm. It is a good "street" lens on my 5d Mk III for grabbing detail shots and close-ups without the weight of its big brother, the f2.8. The not-so-good news for me was that out of the box it frequently failed to autofocus correctly (or in some cases, at all).
Excerpt: This lens is great and brings my ability to capture tighter head shots to a whole new level. I highly recommend it. The only reason I gave it four stars instead of five is that it is limited in lens speed to the f4 aperture stop. However, I could not justify paying twice the money to gain one stop in lens speed. So this lens was my choice for economic reasons. Otherwise it is a great lens for the money.
Pros: Consistent Output, Durable, Lightweight, Nice Bokeh, Rugged, Strong Construction
Excerpt: This lens replaces my Canon 70-300 mm f/4-5.6 IS and is much sharper at longer focal lengths. In fact sharper with 200 mm cropped to equal image size of 300 mm than the old lens. Which is what I wanted. Functions extremely well with control setting on side easy to use. Seems like IS is better, too.
Pros: Does Not Extend, Fast / accurate auto-focus, Rugged, Sharp Images In Raw, Smooth Functioning, Strong Construction
Excerpt: This lens is incredible in every way - super sharp, great DOF, and much smaller and lighter than its f2.8 counterparts. However, in the end it could not compete with the speed and new optics of the f2.8 ver2, so I returned it and made the upgrade. But for the money and if you're not planning to show in any low light, this lens is a great value and makes beautiful images.
Excerpt: I had been debating between this lens and the 70-200mm f/2.8L non-IS. I'm very glad I went with the f/4L IS because of the smaller size and the IS. There is a clear difference in sharpness when I have the IS turned on in lower light conditions. The lens is very sharp, and I really don't miss not having the f/2.8.
Excerpt: I use this almost as a everyday lens. Primarily for wildlife and animals around the house and some minor league baseball games. Works great as long as you have ample light given it is an f/4. Although it can get some great shots of the moon.There is a slight mechanical whir when you autofocus, it worried me at first but after looking into it there is nothing wrong it is a normal thing for the lens to do.
Pros: Consistent Output, Easily Interchangeable, Fast / accurate auto-focus, Lightweight, Nice Bokeh, Rugged, Strong Construction