TOS revealed a variety of advanced sensing systems aboard the Enterprise
. Today's optical, radio and X-ray telescopes may be very primitive by comparison. When Kirk asks for a magnification on the bridge viewscreen, what are we seeing? Is it an actual visible light image of what is outside the ship taken by an optical telescope? Or is it a picture synthesized out of those advanced sensing systems, like synthetic aperture radar today (which can look very photographic) or false color images processed by a computer?
Air traffic radar today is very different from the crude devices used during World War II. Among the developments are discriminator circuits which squelch anything the operator does not want to see. That is, the radar can be finely tuned to see what the users want and/or expect to see. I suppose situations might arise when one wants a "naked eye," unfiltered view of what is outside the ship. But as Zap noted, optical speed-of-light observations aboard an FTL starship are as useless as, oh, an agro "greenhouse" spaceship in orbit around Saturn, or the proverbial screen door on a submarine.