A method generates an image for display by deriving an expected depth of field for the image and by generating the image for display by the display device by applying a blurring function. The expected depth of field is derived with respect to a point of focus in the image, in response to lighting conditions of the environment represented by the image. The blurring function is applied to simulate the expected depth of field of the image by blurring as a function of apparent spatial depth within the image. The degree of blurring applied to a closer depth region, in an apparent depth direction, to the point of focus is lower than the degree applied to a further depth region from the point of focus. Variation of the blurring function with respect to depth separation from the point of focus depends upon the expected depth of field.