In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
Q: In photography , a multiple exposure is when a single frame of film is taken more than once .
A: 
In photography and cinematography , multiple exposure is a technique in which the camera shutter is opened more than once to expose the film multiple times , usually to different images .