The thing that seems a bit weird to me is that the constant light intensity graduation (fig 1) appears much more even/linearly monotonic to me than the perceptual one (fig 2) which seems really off at the ends, kind of sticking to really really dark black for too long at the left end, shifting to white too fast at the right end.
You may want to check your display settings. Possibly too much contrast.
Many TVs have horribly excessive color saturation and contrast settings by default, in order to look sharp and colorful (specifically, more sharp and colorful than the next brand) at the store. Maybe that applies to computer monitors too.
