(written from a Production point of view)
John Finger (18 August 1925 – 26 August 2005; age 80) was a cinematographer who acted as an additional director of photography on the Star Trek: The Original Series episode "Requiem for Methuselah", replacing Al Francis, who was unavailable for part of the shoot. He was not credited on-screen for his contribution. 
Finger was mostly known for his work on sitcoms, having been the regular director of photography on fellow Desilu Productions show Gomer Pyle, USMC at the same time that TOS was in production. He was also a frequent collaborator with noted sitcom director James Burrows, serving as the director of photography on nearly every episode of Cheers (starring Kelsey Grammer, Kirstie Alley, and Bebe Neuwirth) and its spin-off The Tortellis, along with the pilot episodes of Valerie and Dear John. Marvin V. Rush and Howard Block frequently served as his camera operators during this period.