A method of exposure control in an image pickup apparatus includes determining whether a zoom lens has been moved, determining whether an F value obtained from information about focal position of a focus lens linked to movement of the zoom lens has changed, estimating a variation in the focus luminance before and after a change in the F value from the F values before and after the change when the F value has been changed, changing the shutter speed determined according to a focus luminance before the change to a shutter speed determined according to the focus luminance after the change, based on the estimated variation in the focus luminance, and changing a frame rate determined according to the focus luminance before the change to a frame rate determined according to a focus luminance after the change according to the changed shutter speed.