On the one hand, their retinal receptors, like those of birds, have superior bandwidth to a human's eyes, and yet it is assumed that because of their "pixel count" that their overall vision is inferior. On the other hand, we are discovering that it is not pixel count that determines image quality so much as pixel size, and cameras now exist with low pixel count that deliver superior images to cameras with a high pixel count. Ultimately, it is how the visual information delivered by those pixels is processed that determines image quality, and that is something we will probably never know. I have always thought that the apparent "multiple images" of the compound eyes of the fly are in all likelihood processed into a single image, and that our perception of what the fly sees should extend beyond the compound lens into the fly's core processor, another thing we will probably never know any more about.