Human eye The upper end of the range is given in terms of normal visual performance as 10 cd/m (100,000,000 or one hundred million candelas per square meter). The eye includes a lens similar to lenses found in optical instruments such as cameras and the same physics principles can be applied. The pupil of the human eye is its aperture; the iris is the diaphragm that serves as the aperture stop. Refraction in the cornea causes the effective aperture (the entrance pupil) to differ slightly from the physical pupil diameter. The entrance pupil is typically about 4 mm in diameter, although it
As Far as the Eye Can See As Far as the Eye Can See As Far as the Eye Can See is the debut album of Welsh alternative rock band People in Planes (or second album overall, as 2002's "Splendid Animation" was released under the previous band name of Tetra Splendour), released on 28 March 2006. After being dropped by EMI, the band recorded a new album at Wales' Monnow Valley Studio, containing new songs (with newly hired keyboard player Ian Russell) and unreleased Tetra Splendour material. The music video for the album's first single, "If You Talk Too Much (My Head Will Explode)", was directed by