Table S1.
Cephalopod retinal image quality budget
| Term | FWHM (μm) | h Dependence | λ Dependence |
| Photoreceptor size | 5 | None | None |
| Retinal surface displacement | 1 | ∝h | None |
| Cross-talk between photoreceptors | Neglected (in the text) | ∝h | Unknown |
| Residual spherical aberration | 10 at full aperture | ∝Δh for annular pupil | None |
| Diffraction with d = 1 mm; on-axis pupil | 6 | ∝h−1 | ∝λ |
| Diffraction with d = 8 mm; on-axis pupil | 0.75 | ∝h−1 | ∝λ |
| Other achromatic aberrations | 20 at full aperture | Unknown, likely ∝h | None |
| Chromatic aberration with d = 1 mm; on-axis pupil | 6 | ∝h | None |
| Chromatic aberration with d = 8 mm; on-axis pupil | 48 | ∝h | None |
| Chromatic aberration with semiannular pupil | 61 | ∝h | None |
The columns present the various aberration phenomena, the resulting Gaussian–PSF-equivalent FWHM, and the dependencies on ray height h and wavelength-λ. Chromatic aberration is the dominant contribution to image blurring down to 1-mm pupil diameters. The quadrature sum of the various contributions for the semiannular pupil is 65 μm and dominated by chromatic blurring. These values correspond to an f/1.2 lens with a 12-mm diameter.