Our eyes are incredibly sensitive to light. They adapt to changing conditions to allow us to navigate through the world. But then there's the brain. Wonderfully adapted to identifying patterns, which is pretty handy with making sense of what the eyes see, however, it (or we) trick our selves into seeing what is not there. So while of course we can see great detail in bright light, our brains in concert with our eyes attempt to pick out detail, or rather fill in detail in low light.
Now this is all well and good in a survival situation. However, when painting a scene where there is a mix of light and shadow, this is a disaster, or at best, an illustration. The reason is, we don't actually perceive details in shadows, unless we are exclusively focused on the shadow. So, to more realistically render a scene, we therefore, have to leave out the details in the shadows... and let the brain of the observer, do that work for us.
That is the real magic of art, (all of the arts), is have the audience perceive what is not really there, and yet to be moved by it.
"Dusk", 24 x 30cm, oil on canvas