The change in speckle size with lens aperture can be observed by looking at a laser spot on a wall directly, and then through a very small hole. The speckles will be seen to increase significantly in size. Also, the speckle pattern itself will change when moving the position of the eye while keeping the laser pointer steady. A further proof that the speckle pattern is formed only in the image plane (in the specific case the eye's retina) is that the speckles will stay visible if the eye's focus is shifted away from the wall (this is different for an objective speckle pattern, where the speckle visibility is lost under defocussing).