iphone – What is the maximum light intensity of the front and rear flash (flash on the screen)?

The title of the question says it all, I have gone through the specs, but I have not found any information about the light intensity of the back and the flash before you go. 39, an iPhone 6 (the front flash is emulated by increasing the brightness of the screen). Specifically, I am interested in the maximum intensities for the back and front flash.

Is it available somewhere or was it measured by someone?