Without question, the T1i/500D's onboard flash unit is a handy complement to existing-light shooting. You can use it to add just a pop of flash for subjects that are backlit, to balance the exposure for combined outdoor and indoor scenes, and in low-light scenes to ensure that there is no blur from handholding the camera at slow shutter speeds. Once you understand both the flexibility and the limitations of the flash, you'll have another tool that helps ensure tack-sharp, well-lit images in scenes where you might not have gotten these results without using the flash. And, most important, there is enough control that you can also avoid the sterile, overly bright, deer-in-the-headlights images that are commonly associated with flash use.

First, though, it's important to understand a few aspects of the built-in flash that help you know when to use it and what to expect from it.

The built-in flash also offers good versatility and features overrides, including Flash Exposure Compensation (FEC) and Flash Exposure Lock (FE Lock) covered later in this chapter. In addition, many flash options can be set on the camera's Flash Control menu when you shoot in P, Tv, Av, M, and A-DEP modes.

Flash Control menu options include the ability to turn off firing of the built-in flash and an accessory flash, shutter sync with first or second curtain, and Evaluative or Average metering. The T1i/500D also allows you to set Custom Functions for an accessory EX-series Speedlite through the Shooting 1 (red) camera menu — a handy feature that enables you to use the camera's larger size LCD to set up external flash functions. Control of Red-eye reduction is also provided on the Shooting 1 (red) menu.

Figure 7.2. For this image, I used the built-in flash with the default Evaluative flash metering option that's adjustable under the Built-in flash control options on the Shooting 1 (red) menu. I shot in Av shooting mode with C.Fn-3 set to Option 0: Auto. Exposure: ISO 200, f/5.6, 1/125 second.

In the following images, you can see how the different flash options for the built-in flash change the exposure and look of the images. My personal preference is to have the most natural-looking result but with the pop of a little flash light that brings the subject visually forward in the frame.

Figure 7.3. For this image, I used the built-in flash but changed to the Average flash metering option on the Built-in flash control menu. The flash output increased significantly and the mannequin is overexposed. Exposure: ISO 100, f/5.6, 1/125 second.

Table 7.1 shows the behavior of the flash in each of the Rebel T1i/500D's Creative Zone shooting modes. Table 7.2 shows the approximate effective range of the flash with the Canon EF 18-55mm lenses.

In some low-light scenes, you may want to shoot without the flash, but the camera often cannot focus due to the low light, or it takes the camera a long time to focus. In these situations, you can set up the Rebel to use the flash's autofocus-assist (AF-assist) beam. Then you pop up the flash, half-press the Shutter button, and the autofocus-assist beam fires to help the camera establish focus. In these scenes, you can keep the flash from firing but still use the flash's AF-assist beam to help the camera to establish focus.

Before you begin, ensure that the autofocus-assist beam firing is turned on in C.Fn-8. If you're using an accessory Canon Speedlite, you can alternately choose Option 2: Only external flash emits to use only the Speedlite's AF-assist beam.

To use the flash's AF-assist beam for focusing but not use the flash, follow these steps:

A disadvantage of flash exposure in portraits of people and pets is unattractive red in the subject's eyes. There is no sure fix that prevents red eye, but a few steps help reduce it. First, be sure to turn on Red-Eye Reduction on the T1i/500D. This option is set to Off by default. Before making the picture, have the subject look at the Red-Eye Reduction lamp on the front of the camera when it fires at the beginning of a flash exposure. Also have the room well lit.

To turn on Red-Eye Reduction, follow these steps:

One way to modify flash output is by using Flash Exposure Lock (FE Lock). Much like Auto Exposure Lock (AE Lock), FE Lock allows you to meter and set the flash output on any part of the scene.

With FE Lock, you lock the flash exposure on a midtone area in the scene or any area where exposure is critical. The camera calculates a suitable flash output, and locks or remembers the exposure, and then you can recompose, focus, and make the picture.

FE Lock is also effective when there are reflective surfaces such as a mirror, chrome, or glass in the scene. Without using FE Lock, the camera takes the reflective surface into account and reduces the flash, causing underexposure. Instead, set FE Lock for a midtone area in the scene that does not include the reflective surface, and then make the exposure.

To set FE Lock, follow these steps:

FE Lock is a practical technique to use when shooting individual images. But if you're shooting a series of images under unchanging light, then FEC is more efficient and practical.

Flash Exposure Compensation (FEC) is much like Auto Exposure Compensation in that you can increase or decrease flash exposure up to +/-2 stops in 1/3-stop increments. A positive compensation increases the flash output and a negative compensation decreases the flash output. The compensation is applied to all flash exposures until you reset the compensation back to 0.

As with non-flash exposure, the camera is calibrated for an "average" scene of 18 percent gray, and flash exposures can be thrown off by very light and very dark subjects or scenes. As a result, very light subjects may need increased flash exposure ranging from +0.3 to +1 stop. Dark-toned subjects may need a flash reduction of approximately −1 to −1.3 stops. Some experimentation is required because subject and scene tonality varies.

If you use flash compensation to create a more natural-looking portrait in daylight, try setting negative compensation between −1 and −2 stops. Also be aware that in bright light, the camera assumes that you're using fill flash to reduce dark shadows and automatically provides flash reduction. Experiment with the Rebel T1i/500D in a variety of lighting to know what to expect.

Figure 7.4. This image was made using no flash in overcast, late-afternoon light. Exposure: ISO 200, f/5.6, 1/125 second.

Figure 7.5. For this image, FEC was set to −1 Exposure Value (EV). The lowered flash exposure provides a more natural appearance than full flash would provide (compare to Figure 7.2). I used Av shootin mode and set C.Fn I-3 to Auto so the camera would balance existing light with the flash light. Exposure: ISO 200, f/5.6, 1/125 second, Av mode.

It's important to note that if you use FEC, you may not see much if any difference with negative compensation because the T1i/500D has Auto Lighting Optimizer turned on by default for all JPEG images. This feature automatically corrects images that are underexposed or have low contrast. So if you set FEC to a negative setting to reduce flash output, the camera may detect the image as being underexposed (too dark) and automatically brighten the picture. The next series of images shows the advantage of fill flash with FEC over using no flash.

If you're using FEC, it's best to turn off Auto Lighting Optimizer by choosing Option 3: Disable for C.Fn-7. Auto Lighting Optimizer remains disabled in P, Tv, Av, M, and A-DEP shooting modes until you enable it again.

If you use an accessory Speedlite, you can set FEC either on the camera or on the Speedlite. However, the compensation that you set on the Speedlite overrides any compensation that you set on the T1i/500D's Shooting 1 (red) camera menu. If you set compensation on both the Speedlite and the camera, the Speedlite setting overrides what you set on the camera. In short, you can set the compensation either on the Speedlite or on the camera, but not on both.

Figure 7.6. For this image, FEC was set to −2 Exposure Value (EV). This image provides the most natural-looking image to my eye because it adds a little light to the face while balancing the existing light in the background. Exposure: ISO 100, f/5.6, 1/125 second.

FEC can be combined with Exposure Compensation. If you're shooting a scene where one part of the scene is brightly lit and another part of the scene is much darker — for example, an interior room with a view to the outdoors — then you can set Exposure Compensation to −1 and set the FEC to −1 to make the transition between the two differently lit areas more natural.

To set FEC for the built-in flash, follow these steps:

To remove FEC, repeat these steps, but in Step 2, press the left or right cross key to move the tick mark on the exposure level meter back to the center point.

With the T1i/500D, many of the onboard and accessory flash settings are available on the camera menus. The Shooting 1 (red) menu offers onboard flash settings including the first or second curtain shutter sync, Flash Exposure Compensation, and E-TTL II or Average exposure metering.

Figure 7.7. For this image, I used the built-in flash at a −2 FEC to light the center of these cherry blossoms. Exposure: ISO 200, f/8, 1/125 second.

When an accessory Speedlite is mounted, you can use the Setup 2 (yellow) menu to set FEC and to set Evaluative or Average flash metering. In addition, you can change or clear the Custom Function (C.Fn) settings for compatible Speedlites such as the 580 EX II. If the Speedlite functions cannot be set with the camera, these options display a message notifying you that the flash is incompatible with this option. In that case, set the options you want on the Speedlite itself.

To change settings for the onboard or compatible accessory EX-series Speedlites, follow these steps:

The Rebel T1i/500D is compatible with all EX-series Speedlites. With EX-series Speedlites, you get Flash Exposure Bracketing and flash modeling (to preview the flash pattern before the image is made).

When I travel to shoot portraits on location, I take three Speedlites with stands and silver umbrellas. This setup is a lightweight mobile studio that can either provide the primary lighting for subjects or supplement ambient light. Like most photographers, I also use a variety of reflectors.

In addition to the Speedlites, I use Canon's Speedlite Transmitter ST-E2. This transmitter wirelessly communicates with multiple Speedlites set up as groups or individually so that they fire at the same flash output. Alternately, you can set up slave units and vary the flash ratio from 1:8 – 1:1 – 1:8.

Figure 7.8. This is the back of the Canon Speedlite Transmitter ST-E2. It enables you to set up groups of flash units, control the channel in case other photographers are shooting wirelessly nearby, and to set up the lighting ratio.

In addition, if you have a studio lighting system, you can use the T1i/500D for studio shooting. Just buy a relatively inexpensive hot shoe-to-PC adapter to connect the studio lighting sync cord, or a wireless hot-shoe trigger can be used as well. Then set the Rebel to 1/200 second or slower, the sync speed for flash use. I recommend the Wein Safe-sync hot-shoe adapter to regulate the sync voltage of studio strobes to a safe level of 6 volts to protect the camera.

While it's beyond the scope of this book to detail all the lighting options that you can use with one or multiple Speedlites, I'll cover some common flash techniques that provide better flash images than using straight-on flash.

Figure 7.9. The Canon Speedlite 580EX II accessory flash. The T1i/500D includes a waterproof jacket around the hot shoe that matches up to the 580EX II seal to keep water from getting into the electrical connection in wet weather.