It is the successor of the?Canon EOS 350D, and upgrades to a 10.1?megapixel?CMOS sensor, a larger continuous shooting buffer, an integrated?image sensor?vibrating cleaning system (first used in a Canon EOS DSLR), a more precise nine-point auto focus system from the?EOS 30D, improved grip, and a bigger 2.5-inch (64?mm)?LCD?with 230,000 pixels and a larger viewing angle which replaces the top status screen.
The 400D uses the?DIGIC II?image processor, as is used in the 350D. Unlike the 350D, the 400D file numbering system holds 9,999 pictures as opposed to 100 photos in one folder. Support for the?Media Transfer Protocol?(MTP) USB protocol is available since version 1.1.0.