Industry body CEA has defined a minimum standard for ‘4K’ video and has chosen the terms ‘Ultra High-Definition’ and ‘Ultra HD’ to describe it. The consumer electronics body, which includes most major camera makers, has concluded that devices must be capable of showing 3840 x 2160 pixel video to be classed as Ultra HD devices. The move helps solidify the definition of 4K video, which has been used to describe a number of pixel dimensions. The 3840 x 2160 definition dates back to the Society of Motion Picture and Television Engineers’ 2007 specification.
News: Digital Photography Review (dpreview.com)