If you go from outdoors on a really sunny day into a dark place, you usually barely see anything. Your pupils open up very fast to become as large as possible but human eyes take a long time to fully adapt to darkness and reach their optimal sensitivity to low light conditions.
The human eye can function from very dark to very bright levels of light; its sensing capabilities reach across nine orders of magnitude. This means that the brightest and the darkest light signal that the eye can sense are a factor of roughly 1,000,000,000 apart. However, in any given moment of time, the eye can only sense a contrast ratio of 1,000. What enables the wider reach is that the eye adapts its definition of what is black. https://en.wikipedia.org/wiki/Adaptation_(eye)
The eye takes approximately 20 – 30 minutes to fully adapt from bright sunlight to complete darkness and becomes 10,000 to 1,000,000 times more sensitive than at full daylight. In this process, the eye’s perception of color changes as well. However, it takes approximately five minutes for the eye to adapt from darkness to bright sunlight. This is due to cones obtaining more sensitivity when first entering the dark for the first five minutes but the rods taking over after five or more minutes.Sensory Reception: Human Vision: Structure and Function of the Human Eye” Encyclopædia Britannica, vol. 27, 1987 Cone cells are able to regain maximum retinal sensitivity in 9–10 minutes of darkness whereas rods require 30–45 minutes to do so. Dark adaptation is far quicker and deeper in young people than the elderly. https://www.sciencedirect.com/science/article/pii/S0042698999000929?via%3Dihub