The Canon EOS 5D Mark II is a 21.0 effective megapixel full-frame CMOS digital single-lens reflex camera made by Canon, the first Canon EOS camera to have video recording capabilities. It succeeds the EOS 5D and was announced on 17 September 2008.

A full-frame DSLR is a digital single-lens reflex camera (DSLR) with a 35 mm image sensor format. Historically, 35 mm was one of the standard film formats, alongside larger ones, such as medium format and large format. The full-frame DSLR is in contrast to full-frame mirrorless interchangeable-lens cameras, and DSLR and mirrorless cameras with smaller sensors, much smaller than a full 35 mm frame. Many digital cameras, both compact and SLR models, use a smaller-than-35 mm frame as it is easier and cheaper to manufacture imaging sensors at a smaller size. Historically, the earliest digital SLR models, such as the Nikon NASA F4 or Kodak DCS 100, also used a smaller sensor.