Canon EOS-1D Mark IV

Canon EOS-1D Mark IV vs. Nikon D3S

With its super-fast shooting speed (10 frames per second) and low-light prowess, the Canon EOS-1D Mark IV competes directly against the top-rated professional digital single lens reflex (SLR), the Nikon D3S (*Est. $5,200 body only). If you've already invested in a lot of Canon lenses and need a tough, top-of-the-line camera for demanding jobs such as photojournalism and sports shooting, critics say you won't be disappointed in the EOS-1D Mark IV. However, the Nikon D3S still slightly outclasses the Canon in tests, for several reasons.

In low light, experts report that the Nikon D3S produces usable images all the way through its stratospheric range (up to ISO 102,400), while the Canon proves grainier at extremely high ISOs. Both cameras shoot rapidly, with fast autofocus, but the Nikon edges out the Canon in some sports-shooting tests. The Canon offers higher resolution (16.1 megapixels versus 12.1 for the Nikon), but the Nikon's full-frame sensor delivers a better dynamic range than the Canon's smaller, APS-H crop sensor (although testers say both produce very crisp, accurate images).

HD video performance

The Canon does hold an edge when it comes to video. Both cameras can shoot high-definition video, but the Nikon D3S stops at 720p while the Canon EOS-1D Mark IV shoots full 1080p HD. DPReview.com calls the Canon's footage "excellent," with very little distortion caused by the camera's rolling shutter. Imaging-Review.com's Andrew Alexander finds the Canon's movie mode "complete enough for the main purpose of capturing video clips for news," but the camera itself can be awkward to use as a camcorder: You can't use the eyepiece to frame your shots, and "holding a three-pound camera with arms outstretched as focus is judged on an LCD screen is challenging for more than the shortest of clips, especially if a lens of any weight is employed. For serious movie recording, this isn't the camera you want." If shooting HD video is really important to you, Alexander prefers Canon's lighter-weight full-frame camera, the Canon EOS 5D Mark II (*Est. $1,900 body only).

Professional photographers report that -- like the Nikon D3S -- the Canon EOS-1D Mark IV is built for heavy-duty use, with a dust- and water-resistant magnesium-alloy body, a shutter designed to last for 300,000 shots, dual memory card slots and practically every feature you could think of (except neither camera has pop-up flash). But it's heavy (3 pounds with the battery, not including the lens), bulky, expensive, and probably overkill even for serious enthusiasts. Plenty of pros report that they actually prefer lighter, less expensive cameras for everyday use, such as the Canon EOS 5D Mark II.

DPReview.com publishes an extraordinarily thorough review of the Canon EOS-1D Mark IV. Tests at Imaging-Resource.com and Shutterbug also include plenty of detail. EPhotoZine.com and PhotographyBay.com both test the Canon EOS-1D Mark IV against its main rival, the Nikon D3S. Amazon.com posts owner-written reviews for the Canon EOS-1D Mark IV.