You have heard of the term ‘movie footage’ or footage being used in a video sense? Do you know why it is referred to as footage in the first place? If you were under the impression that it would be some complicated movie terminology that is difficult to understand or comprehend, then think again. Instead, the actual answer is far more apparent than you would have initially thought.
The actual reason why it is referred to as footage is simply because of the early days in film when the reel of film itself was measured in feet. Yes, it is all to do with a simple measurement and people then spoke in terms of recording footage since they were using up a certain actual measurement of tape.
Even though the way in which things are recorded has now changed due to differences in technology, it seems that this is something that has just stuck because you can hardly imagine referring to it as anything else now.