Might as well make this an Astaire weekend.
Fred Astaire,ever the perfectionist,wanted his dance numbers filmed in long takes with minimal camera movements and cuts. And the dancers’ full figure in the camera frame.
The dance numbers had to be performed flawlessly,or the whole number had to be repeated.
The film technicians at RKO designed what became known as the ASTAIRE DOLLY. The small platform was on tiny wheels, with a mount for the camera operator and the assistant who changed the focus. The head grip was in charge of pushing the dolly around and maintaining a constant distance.
To dolly in and out in film is a continous shot from a single camera, with no editing. It’s as close as Astaire could get to a live performance. The last section of ‘Begin the Beguine’ in BROADWAY MELODY OF 1940 is one continous take of Astaire and Eleanor Powell which goes on for several minutes.
Specifically for these dance numbers, I think Fred Astaire got it right. You sit back, enthralled at the sheer artistry and energy it takes to produce one dance. You can see there is no editing; that the camera starts when Fred goes into motion, and only stops when the dance ends.