There are going to be times when you have to turn to your camera’s built-in fl ash to get the shot. The pop-up fl ash on the 7D is not extremely powerful, but with the camera’s advanced metering system, it does a pretty good job of lighting up the night… or just fi lling in the shadows.
The built-in fl ash will automatically pop up in the Full Auto and Creative Auto modes if the camera senses that there isn’t suffi cient light for your scene. In all other modes (P, Av, Tv, and so on) you’ll need to push the Flash button, located on the front of your camera, to activate it.
The standard fl ash synchronization speed for your camera is between 1/60 and 1/250 of a second. If you set the shutter speed faster than 1/250 of a second, it will be too fast to catch all the light produced from the fl ash. In fact, you’ll fi nd that your camera won’t let you go beyond 1/250 of a second when the pop-up fl ash is activated.
The key to great fl ash photography is controlling the shutter speed. The longer your shutter is open, the more ambient light you can let into your image. If you are photographing a person during a sunset and drop your shutter speed low enough to capture the light behind them, you can add beautiful colors to the background. Using different shutter speeds with a fl ash makes it possible to create some fun and creative shots as well. Let’s take a look at how each of the camera modes affects the shutter speed when using your fl ash.
- Program (P): The shutter speed is automatically set between 1/60 and 1/250 of a second. The only adjustment you can make in this mode is to your exposure compensation by using the Quick Control dial to change the f-stop.
- Shutter Priority (Tv): You can adjust the shutter speed to as fast as 1/250 of a second all the way down to 30 seconds. The lens aperture will adjust accordingly, but typically at long exposures the lens will be set to its largest aperture.
- Aperture Priority (Av): This mode has three custom settings for adjusting the shutter speed when using the fl ash, depending on your needs. The default setting is Auto, which will set your shutter speed and is the recommended setting to start off with.
The built-in fl ash uses a technology called E-TTL II (Evaluative Through The Lens) metering to determine the appropriate amount of fl ash power to output for a good exposure. When you press the Shutter button halfway, the camera quickly adjusts focus while gathering information from the entire scene to measure the amount of ambient light. As you press the Shutter button down completely, a pre-fl ash occurs to meter the light off the subject from the fl ash, and a determination is made as to how much power is needed to balance the subject with the ambient light. This applies to the P, Tv, and Av camera modes.
The default setting for the fl ash meter mode is Evaluative. You can set the meter to Average mode, but that should probably be avoided. Your best results will come from the E-TTL mode.
However, if you have special metering needs, such as a background that is very light or dark, you might consider using the Flash Exposure (FE) Lock to meter off your subject and then recompose your image in the viewfi nder.
USING THE FE LOCK FEATURE
- Press the Flash button on the front of your camera to turn on the built-in fl ash. Then point the camera at the area that you want to base the fl ash exposure on (this is normally your subject).
- Press the Multi-function button (M-Fn), located next to the Shutter button. You will see “FEL” (Flash Exposure Lock) appear on the bottom of the viewfi nder momentarily, and the fl ash will fi re a pre-fl ash to measure exposure. The AE/FE lock symbol (an asterisk) will also appear in the viewfi nder.
- Recompose the scene as you like, focus, and press the Shutter button completely.
The FE Lock will cancel after each exposure, so you have to repeat these steps each time you need to lock the fl ash exposure.
Using the Average metering mode might also require that you tweak the fl ash output by using Flash Exposure Compensation. This is because the camera will be metering the entire scene to set the exposure, so you might have to add or subtract fl ash power to balance out the scene.