>>4050410About one, for the filter I use (60% transmission) The lens itself only passes about 60% at 365nm, iirc. A little fuzzy on that detail, don't quote me on that number. I'm looking at getting a new portrait lens right now, and with that I'm expecting even poorer transmission. Meanwhile, my lights are slowly approaching the level where I'll surpass exposure at peak emissions in summer. I can't risk harming my models. Both on a moral and practical level that is a barrier. If I can somehow scrounge up the cash in the future, I'll get the Baader-U, but as of yet I'm unsure as to whether it'll fit over the front cell of the 240mm lens I'm considering.
TL;DR, less than you thought but more than I'd like
