Excerpt: I bought the lens for wild bird photography. I considered the EF 400 5.6, but I thought I better go with IS. I am a pure amateur hobbyist. I like the portability of the lens. The great close focus (5.9') has been useful in getting images of flowers and insects. Most of my use is at the 400mm, but I like the ability to shorten-up if the subject comes closer. I use it mostly from a monopod, and I am still working to get consistently sharp images of moving birds.
Excerpt: Push-Pull is very quick, just takes time to get used to it. I have had this lens for 3 years. After a year if use I thought this lens was soft on focus. I sent it back to Canon for cleaning and adjustment. They replaced the forward optic lenses and recommended that I change UV filter and micro adjust the lens. I bought a B+W UV filter and completed the micro adjust process. Since then my results have been spectacular. This lens is tack sharp from 6' to infinity.
Excerpt: I have had this lens for 10 days and though had a sore forearm for the first two days - since I prefer to shoot "hand-held" - I seem to have found a way to hold camera to my advantage - no sore arm. While my hand shakes a little when focusing, due to the heavy weight of this lens - the Image Stabilizer feature ensures sharp results. Since this lens offers such clarity I am able to crop photos and still see detail.
Pros: Consistent Output, Fast / accurate auto-focus
Excerpt: I wasn't sure at first if the price of this lens was worth it until I compared it to my other telephoto zoom. I have a 100-300 Canon that's in the $+ range and have used it for several years. The photos taken were pretty sharp and I was pretty happy with it, until I tried out the 100-400. I shot duplicate photos with both lenses using the Canon 70D. Shot for shot the 100-400 photos were clearer and crisper.
Pros: Consistent Output, Easily Interchangeable, Fast / accurate auto-focus, Strong Construction
Excerpt: I just bought this lens again after having mine stolen in Europe. I take this lens where ever I travel. With my trusty 24-105 and this 100 to 400, I have a huge focal range to cover just about any situation. Its a must have for me!
Pros: Consistent Output, Durable, Easily Interchangeable, Fast / accurate auto-focus, Nice Bokeh, Rugged, Strong Construction
Excerpt: I use this lens for pictures of rocket launches at Cape Canaveral, Fl. and wild life photography at Everglades National Park I use it at night time and day time, very good pictures if placed on a tripod for shots at 400 mm with a Canon 7D.
Excerpt: Just bought this to use on an couple upcoming trips. This lens is very well built. It took a few minutes to adjust to using a slide zoom versus a twist type but it works well. Excellent optics.