Built-in flash techniques

Many of the Canon dSLRs offer a pop-up, built-in flash as part of the camera body. The exceptions to this are the professional Mark II and III models, which do not have a built-in flash and require you to use an external flash. Of course, many studio photographers are also using model and flash lighting systems in addition to or separately from an on-camera flash.

The pop-up flash (see 8-4) will open and work automatically if you are using the Program setting or another automatic setting for the camera, assuming the camera has determined there is insufficient light to take an effective image based on its automatic metering. Using the camera in manual or semiautomatic (Tv or Av) mode requires you to press the flash button on the side of the camera that opens and engages the flash.

The pop-up flash on Canon dSLRs, such as the one on this Rebel XTi, is useful for many photographic occasions, but is limited in comparison with an external flash.

If you are using a mounted external flash (connected via the hot shoe), such as a Canon Speedlite, the camera automatically recognizes that it is attached, and overrides the use of the pop-up flash. The same is true if you attach a wireless device to your hot shoe to use the flash remotely.

At certain times the pop-up flash can be useful, and I’ve often wished that my Mark II had one to use in a pinch when I don’t have my external Speedlite available or when I don’t have time to mount it on the camera. But the pop-up flash is limited: It isn’t very powerful, uses the battery, and has a very limited shooting range. For snapshots, though, it’s perfect.

A built-in pop-up internal flash capability is provided with Canon’s entry-level and semipro dSLR models. The built-in flash, while limited in power and functionality, can be very useful in situations where an external flash would be awkward and time-consuming.

As with external flashes, Canon cameras use ETTL II with built-in flashes for highly accurate and sophisticated TTL metering. Additionally, features such as the automated flash popup when the camera is in certain automatic program modes and Red-Eye Reduction makes the built-in flash very handy.

One of the best uses is for fill flash (meaning to use your flash to fill in light where needed, such as in bright light), especially when shooting portraits outdoors where a little extra light will help illuminate the subject more effectively and evenly. On sunny days with bright, overhead midday light, where your subject may get raccoonlike facial shadowing, pop-up fill flash is nearly perfect.

PORTRAITS

If you are relying on your built-in flash when taking a portrait, severe shadowing will occur if you shoot in a vertical (portrait) orientation if there is a wall or other background close behind the subject, as you can see in figure 8-5. Because you are using a built-in flash, you can’t change the direction of the flash head or move it away from the camera. Your best option is to have your subject move farther away from the wall or any objects against which he or she may cast a heavy shadow. If it’s not possible to do so, you may be able to position the subject into a corner of a room, where the angle of the wall may help deflect the shadow and can even potentially give you some bounce flash that will lessen the harsh vertical area of darkness.

The only difference between 8-5 and 8-6 is that 8-5 was taken vertically and 8-6 was taken horizontally In both cases, the pop-up flash on a Canon 20D was used. While some minor shadowing onto the backdrop is evident in the horizontal image, the effect is asymmetrical and far more pronounced in the vertical image. (Both images: ISO 800, 1/60 second, f/4.5, taken with a 20D and an EF 24-70mm f/2.8L lens.)

Another option for avoiding the vertical shadowing is to shoot your image horizontally (as in figure 8-6) and crop it to a vertical image using your image-editing package. Notice how in 8-6 the shadows behind the subject are less prominent. The problem with this, however, is that cropping cuts out a significant portion of the image, meaning your final photo will be lower resolution. If you shoot a subject horizontally and you know it’s going to become a portrait shot in the editing process, make sure you shoot at the largest-possible image size or in RAW, so you will have more data to work with later.

One of the most common annoyances of flash photography is when you take a portrait and the subject appears in the photo with glowing, demonlike eyes. Red-eye occurs when a flash reflects against the retina of a subject’s eye, and it is more likely to occur when using flash simply because the pupils of the eye enlarge in darker areas to allow more light into the eye — precisely when a flash is needed most. External flashes have less of a problem with this because they project light at the subject from a point farther from the lens, so a wider angle; the pop-up flash, conversely, is in a nearly direct line with the lens, so the reflection can be very pronounced (especially with people who have light eyes). Having your camera’s Red-Eye Reduction capability engaged is advisable in most portrait situations.

Red-Eye Reduction works by emitting a short, bright light from the camera’s Red-Eye Reduction lamp, causing the subject’s pupils to contract — thereby limiting the amount of light their eyes can absorb during the actual flash, and reducing, or even eliminating, the reflectivity. While not always perfect, Red-Eye Reduction works very well in many instances. The biggest issue with it, however, is that because it takes a bit longer than a second to process, you can easily lose spontaneity in a candid image.

Sometimes using Red-Eye Reduction isn’t very helpful, primarily because it takes longer for the camera to respond and shoot the photo because it has to fire the preflash Red-Eye Reduction strobe. If you’re trying to catch quick candids with kids, for example, you can easily lose the moment when using Red-Eye Reduction. In these cases, you may be able to reduce the red-eye without turning on Red-Eye Reduction by taping some translucent material to the flash, which softens and diffuses its effect — and limits the amount of direct light being shined into the subject’s eye. Translucent materials you could use on the flash might be a small piece of white silk or cotton, or even a piece of white tissue paper.

So, in what situations is it not advisable to use a pop-up flash?

  • When shooting nonportrait images. This is especially important to adhere to if your subject is moving because using Red-Eye Reduction can delay the photo being taken.
  • When using large lenses, or lenses with big hoods. These can obscure your flash area and you’ll get a cut-off area of light at the bottom of your image. If you need to use a flash, it’s nearly essential that it be an external flash when using this type of equipment.
  • When taking vertical shots. As discussed with portraits, you’re likely to get a big shadow behind your subject.
  • When taking wide-angle shot portraits and scenes, such as of a group of people that stretches to the extent of a wide-angle lens’s range (for example, 24mm or wider). These are difficult to illuminate with a pop-up flash; it just lacks the lateral coverage area as well as the power. Dropping below this can be challenging and generally not advisable.
  • In situations where you need a lot of flash power. For example, if you are lighting a large group of people or where you’re more than ten feet from your subject. While internal flash ranges are specified between a few feet and up to about 30 or more, their power quickly becomes inadequate the farther you are from your subject.

Category: Flashes

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