The light sensitive opsins are activated by light in distinct wavelength ranges. Humans have 3 opsins and very rarely 4 that determine the full wavelength range we can detect and what colors we perceive.
The result of our heritage from a nocturnal primate, that didn't need many opsins
Each ommatidium (facet) has a lens that projects a focused image at the base where pigment molecules called opsins activate a nerve. So, rather than a single image being projected by a lens on a retina of rods and cones the each sees a small portion of the whole image, dragonflies have thousands of narrow-angle images being focused on the light sensitive receptors.
Dragonflies have 13 or more opsins and can see a wider range of wavelengths and that range is divided into more discrete bands of wavelengths than humans see.
It would seem that the compiled image would be very free of distortions typical of wide angle single lenses, they must get a pretty accurate globular view of the world.
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