Tilting the plane of the lens or shifting its axis off center of the film (or digital capture plane) can be used to create a thin line of focus in a photograph that gives the illusion of a very narrow depth of field. This affect in a photograph has become recognizable as what happens when the subject of a photograph is very small, like a very detailed model. I have used both my Canon TS-24 3.5L and software that can mimic the affect to produce some of the images below.
Princes Street Gardens - Edinburgh, Scotland
Straight focus
Tilted focus
Princes Street Gardens. National Gallery of Scotland on the left. Royal Scotish Academy on the right. The castle rock is in the background. The pictures are taken from the top of the Walter Scot memorial.