You know what to do.


Splash setup. The box in the middle is a fishtank. :-)
Four speedlites with rf transmitters are used: 1+2: left and right corner of the tank, shooting through paper pieces as diffusor. 3+4: behind the transluzent backdrop foil (translum foil). Note: Why not just one flash instead of 3+4? Because these flashes get faster with lesser power → adjust power down and use more flashes to avoid blurred shots.
Discussion – 2 comments