A useful list of video aspect ratios

A reasonably complete list of common and usefull video aspect ratios. Ratio expressed as image width to height. Be aware that digital video often has non-square pixels, so a video may have two aspect ratios, a pixel aspect ratio and a display aspect ratio. The below table shows only display aspect ratios, the width to height of the final image after appropriate  stretching. Anamorphic lenses (lenses that squish an image horizontally), were and are often used to make wider images on the same amount of film. The same lens would be used on the projector to unsquish the image. This was a great idea when it came out, but now is purely a preference on the part of the director or producer.