to attach and detach, to put on and remove

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

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

ease / simplicity / lightness, brevity

easy / simple, uncomplicated / brief, light, short

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

camera / video camera / movie camera / surveillance camera

an instant camera

Alternative spelling of フレネルレンズ (“Fresnel lens”)

a Fresnel lens