Enlarged posterior median eyes are more sensitive to light than human eyes by

Value 2000 times more sensitive to light than human eyes
Organism Spider, family Deinopidae, Deinopis spp.
Reference Mammola S, Michalik P, Hebets EA, Isaia M. Record breaking achievements by spiders and the scientists who study them. PeerJ. 2017 Oct 315:e3972. doi: 10.7717/peerj.3972 p.20 2nd paragraphPubMed ID29104823
Primary Source Blest AD, Land MF. 1977. The physiological optics of Dinopis subrufus L. Koch: a fish-lens in a spider. Proceedings of the Royal Society of London B: Biological Sciences 196(1123):197–222 DOI 10.1098/rspb.1977.0037PubMed ID16265
Comments P.20 2nd paragraph: "Best nocturnal eyesight—Net-casting spiders, Deinopis spp. (Deinopidae). The best nocturnal eyesight documented to date is found in the net-casting spiders (Deinopis spp.). They possess enlarged posterior median eyes (see also “Largest eyes”) that are reported to be 2,000 times more sensitive to light than human eyes, thus appearing physiologically designed for detecting movement at night (primary source). It has been suggested that these visual cues are fundamental to net-casting spiders for capturing cursorial prey items (ref Stafstrom & Hebets, 2016, see “Most creative hunting strategies”) (Fig. 3C)." Primary source abstract: "The posterior median eyes of Dinopis subrufus are probably the largest simple eyes found in arthropods, and may reach 1.40 mm in diameter [BNID 116061]. For a lens 1.325 mm in diameter the focal length is 0.771 mm, giving an F-number of 0.58. This, coupled with the large diameter of the receptors (20 µm), means that the light absorbed per receptor will be about 2000 times as great as in a diurnal spider such as a salticid, or in the human eye looking at the same extended field."
Entered by Uri M
ID 116187