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Message: <blockquote data-quote="Gijs van Ginkel" data-source="post: 3624005" data-attributes="member: 82596">Dear all,The discussion about observed brightness comes back over and over again and since that was the case I had in 2013 glued together a review of scientific papers which are of relevance to this matter and among them quite a few text books in the field of optical sciences, monographs, relevant publications etc. The title of it is "Color vision, brightness, resolution and contrast in binocular images"; it is published on the WEB-site of House of Outdoor and it is in English.Basically there are two measurable paramaters which determine brightness: exit pupil and the amount of light entering the eye because of the light transmitted by the binocular. Since our brain is not a computer, but fuctions as a type of "psycho-physical weighing" device the color distribution of the transmitted light (color temperature if you wish) is also of importance for observed brightness, since our brain decides that some colours are considered brighter than others. For that reason the shape of the transmission spectrum is of importance as the binocular producers know very well and they take that into account. I once had a long discussion with one of the leading optical scientists of Zeiss who convinced my that FOV does not have any effect on perceived brightness.If you want to read some text books/studies which give some light on the matter: "Die Fernrohre und Entfernungsmesser" by König und Köhler, third edition, 1953 ; Harry Rutten and Martin van Venrooij, "Telescope optics", 2002; Carl Zeiss, "Handbuch für Augenoptik, 4th edition, 2000 ; Kurt Nassau, "The physics and chemistry of color" 2-nd edition, 2001 ; Paul Yoder and Daniel Vukobratovitch, "Field guide to binoculars and scopes", 2011. Gijs van Ginkel</blockquote>

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