Talk:Snell's window

observer's depth/distance does not affect angle of view
Martin Edge (op cit, p223) observes "I was once under the impression that the deeper you went the more [of snell's window] could be included [in the photograph]. This is incorrect! To photograph the full circle you need a fisheye lens equivalent to a 12mm lens on a 35mm format." In other words, the snell's circle covers 97&deg; of the observer's angle of view regardless of the distance between observer and water surface. ... Why? Is it something to do with "afocal" optical elements ? Redbobblehat (talk) 15:17, 2 September 2008 (UTC)
 * Optical effects are often constant-angle effects. For example, the colored edge of a rainbow is 43 degrees away from the antisolar point, regardless of whether it's made by raindrops miles away or a water sprinkler right in front of you. Hellbus (talk) 00:49, 7 March 2012 (UTC)

97 degree ?
Which angle? ESCapade (talk) 16:00, 21 September 2009 (UTC)
 * θ2. J IM ptalk·cont 11:20, 14 January 2010 (UTC)