Hi Jack- I have a Macbook Air and an Apple 27" Thunderbolt display. The displays are capable of putting out a lot of light- too much for most "normal" indoor lighting conditions. I calibrate both of the displays with the Spyder 3 Elite system and it provides a target brightness based on the ambient lighting at the time of the calibration. The usual brightness setting it calls for is about 110 candelas/square metre which works out to about 4-5 "notches" lower than maximum brightness on both displays.