I had never read anything before about this kinda stuff, interesting tho. I really enjoy how Trek used it, not enough to be cheesy but just enough to add flare IMO...
Off the top of my head I can't remember which episodes they did it in, anybody else wanna chime in?
The fish-eye lens is from both The Tholian Web
, Is There In Truth No Beauty
Trek had some VERY good directors - Joe Pevney, Marc Daniels and Ralph Senensky were all among the busiest directors in TV at the time. Pevney seemed to specialize in the bigger productions, Daniels was the best at using those small ENT sets, and Senensky was their 'sensitive' specialist.
Senesky first used the 9mm fisheye in "Metamorphosis" for the long shots of the Galileo on the planet surface. You can really tell as Cochran seems to be far away from the Galileo but when he runs towards it he gets there in about 5 steps, lol.