I just bought a lux meter from Fasttech to quantify my flashlights output in the future. Problem is I am not quite sure which method is the most accurate way to measure the distance between the flashlight and the lux meter? I don’t think a common measuring tape is really practical as it is not very precise plus over 10m range it is just too troublesome to do so. Is something like a range finder like this usable?
Thank you 