How long will it take for transition lens to change color?

[Payten]

Does it change the color quickly when they are under the sun or have to wait for several minutes?

[Anabel]

Transition lens won't change the color quickly when they are under the sun. It will take them several minutes to change the color.

[Ann]

It doesn't change the color immediately when it is under the sun. It will take seconds or minutes to change up.For first use,it may take longer.