You probably wouldn't be able to see it unless you compare to a similar shot at a "better" aperture. The effect is very much like a small focusing error. See my post #9 with respect to the extent of the effect in terms of "resolving power." As a note the limit is based on the idea that there is a limit to how small of a point that light can be focused down to. This smallest "spot" is called the Airy disk after astronomer George Airy, who worked out the mathematical treatment. The concept of resolving power, in terms of line pairs per mm, can be seen as the application of the idea of two Airy disks next to each other - how close to each other can they be before they merge into a single blob of light? In order to "resolve" a difference, meaning to see two distinct points, they must be separated by some distance; a guy known as Lord Rayleigh made some rules known as the Rayleigh criteria. The names should allow you to look things up should you desire.