As we already use a 100-400mm Zoom IS and 600mm lens this seemed like a good choice to review early on. Jill sometimes gets frustrated as birds are often distant and needs something a bit more.
The 400mm DO IS is perfect for such occasions. The usual contenders such as 500mm and 600mm lenses are bulky and heavy - not ideal for carrying anywhere, and not all locations are convenient to get to. With this lens weighing less than 2kg (compared to 100-400mm IS 1.4kg and the 500mm f/4l IS USM 3.9kg) it can still just about, comfortably, be carried around the neck. Obviously the 400mm f/2.8 IS is a quicker lens but weighs over 5kg.
It worked very well with our aging 1.4 converter which increased focal distance to 560mm on a 5D mark II and 896mm on a 40D or 7d (approx 18 times magnification)making this a contender for both wildlife and sport photographers who want superb quality but due to its high price tag, it is definately for serious photographer.
The two images below of a reed warbler show the full frame and cropped version of the same image. This shows the quality of the lens.
This would be ideal in a rain forest because of its weight and ease of carriage or somewhere equally inaccesable, Also for those less able it works really well using your portable hide and a bean bag (ie out of the car window).
The recommended retail price tag on this lens is a hefty eight thousand pounds but can be found cheaper with some shopping around.
A quick round up
This is a fabulously awesome lens that we really didn't want to send back.
Perfect, particularly for travelling photographers that are worried about getting their precious lens in a plane as part of hand luggage. This can easily be taken aboard, in its small case or even round your neck. It is also for anyone who physically wants more but can't lump one of the big boys round. Ideal for everyone but particularly lady photographers and the disabled.
Sedge warbler withe the 400Do and a 1.4 converter.