-Tripod or two
-Remote trigger system of some sort for your flash
-Cake pan, bowl or anything that will hold water
-Small plastic sandwich bag
-Pin and a Pen
-Towel (for spills)
-Remote shutter release (useful, but not necessary)
If you are scared away already by anything on the list, ie remote triggers, dont be. Especially if you own a Nikon camera. Chances are, you can fire a flash off camera with the equipment you currently own. I cant really speak for any other systems, but you can pick up a set of inexpensive radio jobs for $18 on ebay that will do the trick.
In order to take advantage of Nikon's CLS (creative lighting system) you will need either an SB600 or SB800 (flash) and the pop up flash on your camera. You will set your on board flash to commander and your speedlight to remote, thats it! Confused? Heres how to do it with a D300 and SB800. Menus should be really close with other D bodies but you can check your manual for specifics.
On the camera, go to your custom setting menu
Flash control for built-in flash
Select Commander Mode and set your group A to M or manual and dial in about 1/64th power to start with. You wont need a lot of juice with these as you will be working in close proximity.
On the flash, hold the round sel button until you see this menu
Select remote from the menu, then hit the on off button and you will get this screen
Make sure your on board flash is set to same channel as your speedlight. Mine were both set on channel 3 as you can see in the pics.
If you are using radio triggers, put your flash in manual mode at about 1/64th power and make sure your channels are correct. With the ebay ones, they only have 2, so its pretty easy to get it right.
Still with me? Good. Grab a cake pan or bowl and fill it with water. I filled mine almost to the top. Now we need to set up our super expensive automatic water drip system.
I grabbed a zip lock bag from the drawer and filled it about half way full of water. I then clamped it to a tri pod over my pan and poked a hole in it with a pin. Drip, drip, drip. This gave me a drop about every 2 seconds or so. Perfect.
I used a 16-85mm lens set to 85mm. It let me focus at about 9 inches if I remember right. A macro lens in the 100mm range would make these even better, but we did some with a 50mm as well as an 80-200. Any lens will work really, don't let lens selection stop you from trying these.
The background was a large white envelope propped against a glass. A white 3 ring binder works wonders too.
Set up your flash so that it is pointing at your background/reflector. You want to bounce the light across the surface of the water, not down into it. Set your camera to manual with a shutter speed of 250 and an aperture of around f8.
With the bag dripping in the same spot every time, and your camera on a tripod, take the pen and place the tip in the cake pan where the drips are landing. Now autofocus on the the pen tip and then switch to manual focus. Dont forget to refocus if you recompose, or zoom or move the pan etc.
This entire set up took me about 10 minutes to rig. And that counts 5 minutes of looking for a clamp in the garage.
It takes some practice, but if you follow the steps above, it will eliminate most of the guess work and let you focus on trying to time your shutter clicks. I took around 25-30 shots each time I set this up (3) and always came away with something.
Try out different bowls and pans for effect. You can also set your white balance to tungsten to get a really cool blue color.
White tuppoware bowl with 3 ring binder BG. I moved the binder and flash until I got the split dark/light effect.
Black cake pan
Glass cake pan auto WB. The flash was shooting down into the pan instead of across. You can see the effect.
Glass cake pan Tungsten WB, same flash set up.