From what I've seen explained online, regular drops are around 10 levels *lower* than you max light. Two parts to that. First, light levels from mods don't count for loot-level calculations. And then, 'minimum' loot-level is 5 below that.
I've also seen stuff about luminous/exotic engrams being around 5 levels *higher* than your max level, and maybe a weekly bonus - but don't take my word for it.