The mounting system is perhaps the most important part of an on-camera light system. Some models mount directly to the top of the camera using its accessory shoe. You can mount others using a bracket that attaches to the tripod head. Still others have their own bracket system that attaches to a light-stand post or an on-camera post adapter.

As with the light itself, the kind of mounting system you need depends on how you plan to use the light. If you use the light primarily as a fill/eye light, you can get away with the light mounted directly to the camera's accessory shoe, sitting right on top of the camera. However, if you use the light as your key light, you must use a mounting system that raises the light above the camera and hopefully moves it to the side of the camera, more in the position of the traditional key light. Not only will lifting the light above the camera take the light directly out of your subject's eyes, it will create a more pleasing shadow on your subject's face. If you can mount the light so that it is also off to the side, you will get an even more pleasing shadow that is more in line with the traditional key light you see with standard lights.

Another consideration when looking at on-camera light systems and their mounting capabilities is their ability to use accessories. If you shoot a lot of interviews using the on-camera light as your key light, you will need a mounting mechanism that enables you to use barndoors, add diffusion gels or scrims, use softboxes or light diffusion panels or add color correction filters or gels.

Lighting reporters requires controllable lights, so you are not also lighting up distracting backgrounds or over-lighting the reporter and losing all of the background, so they appear to be standing in a blank wilderness. When shooting weddings, you need to control the light on the bride's face without causing the wedding gown to glow. By using a graduated scrim, barndoors or a graduated neutral density filter, you can reduce the amount of light falling on the dress while lighting her face with a soft diffused light.

These accessories are essential for controlling the light and giving you a light that is soft, controlled and more like a traditional key light. The combination of a soft diffused on-camera light mounted on an arm that lifts the light above and to the side of the camera will eliminate the "deer-in-the-headlights" look you often get when using a standard on-camera l…