The EF-530 DG ST electronic flash features a powerful guide number of 53m (174 ft) and is designed to work with the latest TTL automatic exposure systems of all popular digital and film SLR cameras. It is fully compatible with all Nikon digital SLRs, including the D40 and D40X.

It features automatic TTL flash exposure adjustment for easy operation. The automatic zoom function automatically adjusts the optimal angle of illumination according to the focal length of the lens, ranging from 24mm to 105mm. When using the built-in Wide Panel, the flash can cover a 17mm angle.

For bounce shooting, the flash head can tilt up 90 degrees, left 180 degrees, or right 90 degrees. It can also tilt down 7 degrees, making it easier to use for close-up shots.

In addition to the automatic mode, the flash also has a manual mode, allowing for flash intensity adjustment from full to 1/16. When the flash is fully charged, it emits a "ready" confirmation light, and the flash exposure level can be checked through the camera's viewfinder.

Other features included with this flash are the automatic shutdown function for battery power saving.