Did you ever wondered what softbox you should use when doing portraiture? If you only have one softbox, there is an easy answer, but if you have several sized softboxes, knowing which one to use can usually takes lots of experience and pixel peeping.
J. P. Morgan just put up another one of his Slanted Lens instructional videos, I can do nothing but admire the scientific approach in which he compares the effect of a small, medium and large softbox has. (Hint, it involves placing a 12 by 12 shooting target on the wall).
There is an awesome follow up to that tutorial, using the same photoflex softboxes, on how to actually use softboxes in a shoot.
If you enjoy this kind of videos, make sure to subscribe to the Slanted Lens Youtube channel.