The Nikon D300 is an advanced digital camera used by professionals and provides many ways to use an external flash unit. A "hot shoe" combined slide-in flash mount and electrical connector on top of the camera is the simplest. For more flexibility, a flash can be connected via a sync cord to the flash sync terminal on the camera, or compatible Nikon flashes can use wireless remote triggering. In addition to triggering the external flash, the D300 can communicate information about exposure, flash energy and timing, and focus. Basic external flash operation is simple, but you also can use many complex configurations including multiple flash units.
Use the slide-in "hot shoe" on top of the camera for simple photography. Remove the plastic accessory shoe protector if present and attach the flash unit on top of the camera by sliding the base into the accessory shoe from the back. Lock the flash in place, usually by tightening a horizontal knob on the mounting foot.
Connect an external flash unit with a sync cord for greater mobility. Plug the sync cord from the flash into the D300 screw-in connection on the upper left of the camera. Remove the camera dust protector first if necessary. Be careful of the connector centre pin when inserting the plug, and make sure the threads screw into the camera connector correctly. Tighten the connector by turning the outside ring gently clockwise.
Set the D300 in "commander mode" to control wireless Nikon Creative Lighting System-compatible flashes such as the SB800 or SB900. Press the "menu" button on the upper left of the camera back. Using the multi selector to the right of the screen, select custom menu "e," then sub menu "e3," moving the cursor with the outer buttons up and down and then right to select a sub menu. Moving right from the commander mode selection into the commander mode menu, set the remote channel to match the flash setting by positioning the cursor over the channel number using left or right buttons, and pressing the up or down buttons to change it. Press the "OK" button to finish. Open the on-camera flash that transmits command timing by pressing the button just below it on the left.
Press the rear "menu" button, scroll to the pencil icon, and use custom menu "e" to adjust flash shutter synchronisation and other parameters.
Use the flash exposure compensation button below the on-board flash release to quickly adjust flash exposure and timing. With the button pressed, the front dial below the shutter release adjusts exposure, and the rear dial adjusts flash timing and red-eye effects.
Watch for the flash "ready" indicator as a large lightning bolt to the right of the remaining exposure count in the camera's eyepiece or rear display.
If you are using a non-Nikon wireless remote control such as a PocketWizard, you will use either a hot shoe or a sync cable connection, not the Nikon remote commander mode. When using the quick flash exposure and timing adjustment button, a single button press and release also enables both adjustments for single-hand use.
If you're using one or more Nikon wireless remote flashes with the D300, make sure you release the built-in flash by pressing the button just below it on the left, since the built-in flash provides the signal to control remote flashes.