Abstract: A method to view sharpness of background or foreground object in a viewfinder of an autofocusing camera without having to change the aperture. The method involves first selecting an appropriate relationship between a simulated depth and a plurality of input parameters including aperture value, focal length, and measured depth. A circle of confusion is calculated using the measured distances of a main object and a foreground or background object, and the aperture value at which the picture is to be taken. The circle of confusion is then used to calculate the simulated background or foreground depth using the maximum aperture value, or any aperture value at which the objects will be viewed. Finally, the simulated depth is used to adjust the focal length and display a simulated background or foreground image through the viewfinder. If the sharpness of the simulated image is not satisfactory, a new aperture value can be selected and the simulation process repeated.