Syncing your strobes (or flashes) to your camera has its share of difficulties. Problems include broken cords, misfires, and, if you choose too fast of a shutter speed, an exposure that is only partially illuminated by your lash. But when flash syncing works (Figure 1), you control light. For a photographer, that’s an essential power to have.
A “sync” (short for synchronization) is basically an electrical connection. When a camera’s first shutter-curtain finishes traveling across the sensor or film, an electrical circuit is completed, triggering the strobe. If the second shutter-curtain has already started to move when the first curtain finishes, you get a partial picture since the second curtain is covering part of the picture (Figure 2). Since strobe light actually lasts about 1⁄1000 second, the entire exposure area needs to be open when the strobe is triggered.
This electrical connection should be simple, but there are a couple of reasons it isn’t. First, the electricity in this circuit is not the actual power for the strobes— that would damage the camera. A sync voltage triggers the strobe. Thus, a switch triggers another switch that triggers the strobes. The high-sync voltage used by some older cameras can damage newer models and some older strobes can damage newer cameras. Wein makes a device to protect your camera called a safe sync; it separates your camera from a high-sync voltage (Figure 3).