So if I double the luminance to a bright adapted eye, the total output appears $$2^{0.5}$$ brighter which is a larger increase than that with a dark adapted eye. This seems counter intuitive, shouldn't a dark adapted eye be more sensitive to changes in luminance than a bright adapted eye?
kayvonf
A dark adapted eye is better off handling a wider-range of intensities, since it's likely that when you're in a dark place the ratio of the darkest-dark to the brightest-bright (e.g., a light source) is much larger than when outside in sunlight. Therefore it does make sense for your visual system to try and compress the intensity range more, so it can meaningfully sense more of it.
So if I double the luminance to a bright adapted eye, the total output appears $$2^{0.5}$$ brighter which is a larger increase than that with a dark adapted eye. This seems counter intuitive, shouldn't a dark adapted eye be more sensitive to changes in luminance than a bright adapted eye?
A dark adapted eye is better off handling a wider-range of intensities, since it's likely that when you're in a dark place the ratio of the darkest-dark to the brightest-bright (e.g., a light source) is much larger than when outside in sunlight. Therefore it does make sense for your visual system to try and compress the intensity range more, so it can meaningfully sense more of it.