I'd ask this on pdn, but after my recent barrage of lighting questions there, I figured I'd play it safe and ask here, even though it's not per se a people photography question.(posted 8835 days ago)I'll be using a metz 60ct and that mecatwin thing i put aside at Alt Camera. I've been having great luck with GN calculations (meter is next on my list). But how do you calculate the GN with 2 heads? If they are both aimed at the subject, do I just add the total GN, or subtract the distance of one from the other, or what. For exmple, say I have 1 light on the left side and one on the right, with some of the light from both hitting the front of the model, is the GN doubled? This will be a painful post, I'm sure...shawn