How Cameras Are Used To Influence Players
Cameras used inside games are used for more than just letting the players see the game. They can also be used to influence the players in game - whether to help them, make it more difficult for them or to give them false illusions about something in the game.
In the level 'City Escape' in Sonic Adventure 2, the camera changes from a following 3rd person camera to being a 3rd person camera facing the camera. In this section of the level, Sonic is being chased by a truck. Changing the camera to face the action makes it much more intense for the player because it feels like the truck is coming towards the player. It also makes it a bit more difficult for the player because they can't see what is ahead of them, so unless they know the level well, it is difficult for them to predict where rings, jumps, turns or obstacles are.
Cameras can also be used to help players in game by showing them the exit / collectable / course at the start of the level. One example of this is how in racing games cinematic views of the course are shown before the race starts. These are usually optional and players can skip past these to the start of the race but they help players by giving them a look at the course so they can be prepared for whats to come in the race.
The camera can also be used to make things more difficult for the player. An example of this is where an item or place the character needs to go is off camera - so the player needs to think out of what they can see to reach them (or find them by accident). The camera can also hide enemies by having them in the cameras blind spots.
Resident Evil is a well known example of a game that uses awkward camera and controls to make the game harder and increase intensity and panic.