In order to describe the output of a digital camera, we refer to characteristics, such as aspect ratio, resolution, image frequency (fps), color sampling scheme, output range and contrast characteristic or characteristic curve.

Aspect Ratio and Image Resolution

HD video has a native aspect ratio of 16:9 (1.78:1) and a resolution of either 1920x1080 or 1280x720 square pixels. The resolution is denoted by the number of lines i.e. 720 or 1080. When an HD image is cropped in height, e.g. to an 1.85:1 format, more complicated descriptive terms have to be used (e.g. 1080 1.85:1 crop), Sony and Panasonic use non-square pixels for the formats HDCAM, HDV or DVCPRO HD, whereas the use of 1440 or 1280 “rectangular” pixels in width conduces the reduction of required bandwidth, while the image is then scaled back to correct width for output.

When talking about the digital formats 2K and 4K, we refer to the image container’s width (pixel) instead of its height. 2K generally stands for 2048 pixels and 4K for 4096 pixels in width. As with film, the digital formats also have different sub-formats. According to the current standard published by the Digital Cinema Initiative (DCI), a 2K image has to take up either width or height of a container with 2048x1080 pixels. For 4K images the container size is 4096x2160 pixels. The image can have any aspect ratio inside of this container. A DC 4K image with an aspect ratio of 2.39:1 thus would have 4096x1716 pixels. Joining the Digital Cinema formats are the Full Aperture formats and the Academy formats (see Table).