attaching and detaching; putting on and removing; installing and removing

to attach and detach, to put on and remove

easy / simple, uncomplicated / brief, light, short

ease / simplicity / lightness, brevity

(chiefly in mathematics, physics) for simplicity; for the sake of simplicity

lens (object focusing or defocusing the light passing through it)

camera / video camera / movie camera / surveillance camera

video camera

zoom lens (lens whose focal length can be rapidly changed)

an instant camera