A canon is a composition with strict imitation throughout.
A composition with strict imitation is named a canon. a straightforward and more familiar style of canon is named a round. Form is that the quality of a piece of art which refers to its construction and shape.
In music, a canon may be a contrapuntal compositional technique that employs a melody with one or more imitations of the melody played after a given duration.
Imitative counterpoint occurs if one voice repeats or mimics the patterns just stated in another voice. A canonic process occurs if the responding voice or voices repeat the lead voice exactly. A composition based upon this process could be a canon. Imitation is incessant throughout a canon.
I'm not in this class but what it sounds like Yes when you are taking photos you are aiming to take pictures of things like The vows and the exchanging of the rings and the kiss so it is both telling a story and capturing emotion.