File talk:Lambert2.gif

This picture is not actually correct. It shows the distribution of reflected light for varying incoming light angles, while making it look as if it were for outgoing light angles. A correct image would be a half-circle with every outgoing ray the same length.

84.250.1.146 (talk) 22:55, 9 December 2010 (UTC)


 * Actually it's symmetric. If the incoming beam illuminates a small surface patch, then the diffuse reflection will have a cosine factor for the foreshortening of the patch area, making the pattern as shown, which is correct, I'm pretty sure.  Dicklyon (talk) 07:48, 11 December 2010 (UTC)

NO it is not correct. If the surface is a perfect diffuse emitter, it sends light out equally in all directions. What you are showing is the _magnitude of the diffuse response_ (which would be equal in all directions) for different incident angles of the incoming light.

Abstracte (talk) 21:39, 22 January 2013 (UTC)
 * The figure is correct, but it does not show what you think it shows. Your understanding may not be clear, based on your choice of phrase: "sends light out equally in all directions" is ambiguous to the point of being worthless as a statement. There are several different measures of light that are used in photometry. A perfect diffuse reflector (a Lambertian reflector) produces equal luminance in all directions, but does not produce equal luminous intensity in all directions. This graph shows luminous intensity, not luminance. The graph would benefit from clearer labelling of the quantity that is illustrated.--Srleffler (talk) 03:22, 23 January 2013 (UTC)