As you all know you are not wearing armor when in the Vampire Lord form. And, the mage armor perk in the alteration tree will improve flesh spells.
I just want to know: If I am wearing heavy armor, then I cast a flesh spell, and, then I turn into a Vampire Lord. Will the mage armor perk be active since I am casting the spell wearing armor even though, afterward, I am not?
Best Answer
Yes you do.
This is pretty easy to confirm. You can use the console command player.getav damageresist to see your armor rating without having access to the inventory page:
My vampire lord's armor rating was 325 before casting stoneflesh (which is supposed to be a 60 point armor boost), and after casting it it is now 505 (which is a gain of 180 due to mage armor x3 effect). My normal armor rating went from 492-552 so I didn't gain any perk effects while not in vampire lord form.
Now, considering the spell effect will wears off after a short time, its not too useful for the 3 perk points you must spend, but if you have a mod such as Invested Magic it becomes much more useful.