I'm not sure if my are Transition brand or not but I haven't notice them not changing fast enough when going from indoors or out or vise-versa. My only complaint is that they don't darken inside a vehicle (due to the tinted/treated windshield/window glass I'm told). Also, if it is an issue, they are not polarized. This was a plus for me as I look at a hand held computer screen while outside and polarization makes it very hard to read the screen.