Can you describe what you think is different between properly exposing a film photograph and properly exposing a Voyager vidicon camera photograph? Both use a mechanical shutter to set the exposure time. In what significant way do you say they do not "equate"?
As regards the distance from the planet, if the exposure is properly adjusted for the brightness of the planet's surface, why do you think it matters if that subject entirely fills the photo's frame, or half the photo's frame, or if it only occupies a tenth or a hundredth of the frame? I think your objection is baseless and silly.