Figure 6. Polarization-opponent unit’s signal range, ΔQ, is largest when the R8 length fraction, , is vanishingly small and, without transduction unit saturation (solid curve) does not depend on incident photon flux, Ni.
Saturation progressively decreases ΔQ with increasing Ni (dashed curves). Rhabdom length, l = 100 µm. Degree of polarization d = 0.1. Incident photon flux, Ni: 1 × 105 (blue), 3 × 105 (red), 1 × 106 (green) and 3 × 106 (black) photons s−1.