Using a ring flash of a friend I killed some ten plants of mine. However,
I still have got some nice pictures. :-)
When I took the pictures, the flash was too close (25-30cm) and the plants
burned away afterwards. I never used this powerful flash again. Instead
I use the macro setting of my tele, a high f-stop (32), a stativ, a
remote switch and a video light (2000W) in a safe distance.
Michael