r norman wrote:
> I am not sure just what you mean. The receptors can only adapt to the
> light intensity to which they, themselves, are exposed. There is no
> 'eye averaging' system that measures an 'overall' illumination and
> gets all the receptors to adapt to that level.
Well, thanks - what you explained was exactly what I meant!
> However it is true that generally all the receptors in the eye are subject to an overall
> exposure to the same background light intensity with the image
> producing only a relatively minor change in intensity for specific
So, to take this a bit further, could it be said that this "locally
variable adaptation" increases the contrast range that the eye (the
photoreceptors) is (are) able to deal with?