Canon returned my 100m-400m lens this past Friday, which it repaired under its warranty, shipping it via standard overnight delivery–all at no cost to me. I sent the lens to them via ground on the Friday two weeks prior. It turned out that the image stabilization was not working properly. They repaired the unit, and checked and cleaned the rest of its inners. I’ve had a chance to use it and it now seems to be working fine. Bravo Canon!
It seems I’ve run into a problem with the 100–400mm lens that I purchased this past June. The image in the viewfinder began jumping around when I pressed the shutter button half-way—often this would continue even after shutter release. I contacted Canon’s customer service. Based on my description of the problem they suspected the image stabilization had failed. I sent the lens to their service center and they accepted the lens under warranty. I hope to have it back in about another week. I’ll let you know how the process went, as well as how the lens works when I get it back into the field.
I’ve been using Canon’s f/4.5-5.6 L USM IS lens since June and I must say I’m very happy with it. It certainly takes time to learn since I have no super-telephoto experience. It’s heavy; with the camera it weights about 5 pounds. Nevertheless, even with my slender build, a 3 or 4 hour foray into the field doesn’t seem to pose neck strain, though tripod breaks definitely help.
Although the USM autofocus is very quick, it’s not so effective when photographing birds where there are often leaves or branches in front of or behind the subject, often resulting in an out-of-focus bird. Manual focus seems to be the better alternative under these conditions. When extended to greater magnification, the image stabilization feature helps but you really need to brace the camera against something solid if you’re shooting at less than 1/800 of a second, otherwise the image will not be sharp. As always, it’s important to know your subject so you can be in position with the necessary camera settings to get the best shots. (More photos at: http://sfielding.photoshop.com)