With a photo, you can fire off fifty frames of a whale rolling past and keep the one where its eye is sharp, the light's right, and your buoyancy happened to hold for a quarter of a second. Forty-nine mistakes, invisible. Nobody ever sees them. Video doesn't work like that. There's no ten seconds you can throw away and no best frame to cherry-pick from the mess. The clip has to hold together the whole way through, your framing, your movement, your distance, all of it, for the full duration,...