[COLOR=rgba(0, 0, 0, 0.65098)]Recently I've been studying photometry lately and have been having trouble wrapping my head around the concept of luminance. Tried reaching out to TEEJ without much luck but I'm sure there are plenty others here who can "shine light" upon the topic.
Starting with luminance: I understand that it is the luminous intensity of a light times the area of the surface of that light source. (Differinciating it from luminous intensity) That surface being either the surface of an LED, a mirror, wall, pane of glass or a plane in space, etc. However, I am confused about the solid angle of light involved in luminance. [/COLOR]
[COLOR=rgba(0, 0, 0, 0.65098)]One I've tried to picture this is imagining a cone of light opening up from every single point on a plane (which represents the light source) where each point is the vertex of the cone.
This satisfies the math part where it's the luminous intensity (the cone) times the area of the source (the multiple cones sprouting up from each point on the plane)
However, this creates the phenomenon of the cones of light over lapping with each other. Do these areas contain more light or something? That shouldn't be the case.
Or I can see it as one big cone that uses the whole surface of the light source as sort of it's vertex instead of the usual "point" that were used to.
But if this is the case I don't see how this resulting "cone" of light is the result of a lights luminous intensity times the area of the light source. [/COLOR]
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I am even further confused about this as I've read things like the solid angle is being subtended by the surface of the eye (which would mean the beam angle could be negative if the light source is bigger than the surface of the eye???) or that the solid angle is always parallel like a perfectly straight beam. (Although math wise might work, practically speaking we know that no light simply has a parallel beam.)
[COLOR=rgba(0, 0, 0, 0.65098)]My apologies for just a lengthy, horribly composed, techincal question! Many thanks in advance to everyone![/COLOR]