Nikon CLS system basics

The easiest way to use out of camera flashes is to use wireless radio triggers, like the professional Pocket Wizards or cheaper Chinese made triggers like the Cactus.

When wireless radio triggers are not an option it is worth remembering the Nikon CLS system which uses a commander flash to control a group of remote flashes using pre flashes emitted before the shutter opens.

Most Nikon cameras with a pop-up flash (D80,D90,D200,D300,D700 surely) can enable commander mode to control a group of remote flashes. The SB-800 speedlight can also be used in commander mode.

Just one thing to remember is that the remote flashes need to receive the pre-flashes and that the small sensor is situated on one side, near the battery compartment.

Using the zoom setting in your flash

First, most external flash units can move the flash head to "zoom" the flash, but not all can. Normally, matching the flash zoom with the focal length allows the light to spread as much as possible.

If you set the flash zoom to a longer setting than your lens it will darken the corners of the photo and enhance anything in the center. When using umbrellas, the zoom should cover the entire modifier without spilling over. When using softboxes the flash should be zoomed in to cover the entire surface of the modifier.

Concentrating the beam provides better illumination at a distance. When bouncing from walls or ceilings that act as a huge softbox, a concentrated beam may provide more reflected light, but a wider beam may be softer if the walls or ceilings are close.