capturing footage is capturing your tape or clips from your tape.
digitizing your tape ...

footage is a "film " term. meaning "feet " as in how many feet of film did you shoot. most film releated COST ($) are given in FEET ( footage) ...
film comes in 100 ft, 200ft, 400ft , 1000ft rolls.

IMO persons feel better when they use many "film" terms as they would rather be shooting FILM but shoot video .. many prefer to state they are "filming " or have a film shoot on friday then to say they have a video shoot on friday.
FILM is the standard which all media/camera's is compared against.