The effect that a switch in narration from third-person omniscient to third-person limited has on a story?

The switch basically consists of knowing less rather than more, more like people in real life do. It usually limits itself to knowing what only one character, typically the main character, can know. the correct answers are:

The reader can perceive information only through the filter of a single character.

The switch in narration increases the proximity of the narrator to the main character.