(* In Transference, as Clark looks like Lionel for much of the episode and Lionel looks like Clark, the screen times have been calculated according to the screentime of the character as they appear, regardless of whose body they are in.)
Conclusions[]
Lois has higher screen times than 4 main cast members, despite only being a recurring guest star.
The season marks the first time for a character other than Clark to have the most screen time in more than one episode. Lex has the most screen time on two occasions.
Although Lionel has the most screen time in Transference, John Glover doesn't, due to the transference of the characters into different bodies. Tom Welling actually has the most screen time.
Lex, Clark, Jonathan, Lana and Lionel's screen time decreases this season. Lionel's decreases the most.
Chloe and Martha are the only ones to have an increase in screen time.
This season is the first time that Jonathan has the least screen time within a single episode. In this season it happens on 6 occasions.
Lois and Clark are the only characters to not have a single occasion with the least screen time in a single episode this season.
Commencement is the only 'single' episode to be more than the average time of an episode. It is also the only single episode to be 50 minutes in the series. However, if you count every episode as in one story each, Absolute Justice and Finale are longer than Commencement.