Curvature of field is a lens aberration in which the plane of focus is not flat but slightly curved. As a result, when the centre of an image is in sharp focus, the edges may appear out of focus, or vice versa. This optical effect is most noticeable in wide-aperture lenses and can affect landscape, architectural, and macro photography. Correcting curvature of field is essential for achieving uniform sharpness across the entire image, often addressed through lens design, stopping down the aperture, or using tilt/shift movements on large-format cameras.