Focus adjustment for a projector which includes a projection lens having an adjustable focus position. An asymmetrically focused pattern is projected through the projection lens onto a projection screen, wherein the asymmetrically focused pattern is imaged by the projection lens onto the projection screen with a focus at one portion on the screen that differs with focus at another portion thereof. An image of the asymmetrically focused pattern is captured from the projection screen. A focus adjustment direction is calculated by using asymmetrical aspects of the captured image of the asymmetrically focused pattern. The focus position of the projection lens is driven in the calculated focus adjustment direction so as to move from an out-of-focus state of the projection lens toward an in-focus state.