Lighting effects in-game since the BETA version of ARMA 3 have been 'tweaked'.
In the Video Options menu, there are no other 'light' specific settings apart from the 'Dynamic Lights' options. There are no options to scale up lens flare generated from lights in ARMA 3 to players own personal needs. We are on PC, where changes can be reversed or increased, completely under the players own risk.