>>3126805When you stop down a lens usually it gets sharper and better looking. It also gets darker. The main reason someone would use a lens wide open is either for background separation or lack of light. Because he has a flash and he is shooting against a wall he can get a separation from the background by stopping the lens down. This makes sure that the subject looks sharp through and not just on her eyes. This also kills any ambient light that might be in the room other than the flash. Owning like 1 speed light can make it so you can make really nice photos, though it would be best to have 3 strobes if you can afford it.
t. someone who took a single photography class in college to satisfy my art requirement, Class didn't really have flashing and light work though, but I think I saw a digitial rev video on taking portraitures with one light. One flash + cheap camera + plastic soft box is enough to make pics that really impress normies.