- Capturing the image
- Camera settings
- Care and maintenance
- Custom functions
- Digital camera features
- Digital image file
- Digital image size and preview
- EOS MOVIE
- Exposure settings
- Flash basics
- Speedlite compatibility
- Speedlite range
- Speedlite zoom
- Flash on camera
- Dark backgrounds with flash
- Fill in flash
- Flash exposure lock and compensation
- Wireless flash
- Macroflash photography
- Bounce flash
- Flash synchronisation
- Stroboscopic flash
- Studio-style flash lighting with Speedlites
- Integrated Speedlite Transmitter
- Remote Release
- Focus points
- Image download
- Image compression
- Image information
- Image verification
- Introduction to digital photography
- Focal length
- All about apertures
- Lens speed
- Focusing and depth of field
- Black or white lenses
- Coloured rings
- Lens mount
- EF-S and field of view
- L-series lenses
- Fluorite, aspherical and UD lenses
- Prime and zoom lenses
- Image stabilisation
- Tilt and shift lenses
- Extension tubes
- Macro lenses
- Close-up lenses
- DO elements
- Fisheye lenses
- SubWavelength structure Coating
- Media cards
- Panoramic images
- Remote photography
- Scanning & copying
- Storage and archiving
- The digital darkroom
- White balance
Flash: Fill in Flash
Using flash in daylight sounds strange, but it is one of the most useful techniques available. Daylight flash is often called fill-in flash, because it adds detail to shadow areas of your subject.
If your camera has a built-in flash, there is nothing easier than adding fill-in flash. Just set the full auto (green square) shooting mode and the flash head will pop up and fire with just the right amount of light to give a perfect fill-in flash picture.
It works like this. Your camera divides the viewfinder image into a number of zones and takes a separate meter reading from each. If the reading from the centre of the frame is the strongest, or there is little difference between the different readings, the flash remains inactive. But if the centre meter reading is weaker than the surrounding readings, the camera assumes that the subject is back lit.
In full auto mode (and also the portrait and close-up PIC modes), this back-lit recognition activates the flash.
Of course, the system is not perfect. There can be situations where the central subject area is dark, but fill-in flash is not appropriate. Here, you can switch to another shooting mode to disable the automatic fill-in flash facility.
However, it is actually better to work the other way round. Rather than switch off fill-in flash when you don’t need it, switch it on when you do. It is easy to recognise situations where fill-in flash will help − and making the flash fire when you want it to is very straightforward.
The aim with fill-in flash is to give the film or sensor correct exposure for the daylight, plus enough flash exposure to add detail to the subject’s shadows. Too little flash leaves the shadows in place, too much gives the image an artificial appearance. In the past, good fill-in flash required measurements and calculations. Today, your EOS camera does all the work. Set a suitable shooting mode (see next page) and the camera will come up with the correct shutter speed or aperture for a well-balanced daylight flash image.
Built-in flash units are not very powerful. At most, the guide number will be 13 (metres, ISO 100). If you divide the guide number by the aperture used for the camera exposure, you get the maximum subject distance. So if you are shooting at an aperture of f/5.6, the subject you want to be affected by fill-in flash should be no more than about 2 metres away when you use a film speed setting of ISO 100.
The built-in flash found in many EOS models is perfect for fill-in flash photography. Being close to the camera lens, it does not throw any shadows across the subject. This means there is no conflict with the shadows thrown by the sunlight. And the low power of the built-in unit is not generally a problem as the subject will usually be within a few feet of the camera. Here is a three-step guide to using the built-in unit for fill-in flash:
- Raise the built-in flash head. Most EOS models have a small button marked with a forked arrow near to the built-in unit. The flash head will pop up when you press the button.
- Set the camera shooting mode to aperture-priority (Av). Set the aperture to f/5.6 or f/8. Check that the shutter speed shown in the viewfinder is not blinking (if it is, alter the aperture setting until the speed value is steady).
- Frame your subject and press the shutter button. In most situations, the camera will automatically give a well-exposed image that balances the daylight with the flash. When you have finished taking fill-in flash pictures, press down on the flash head to close it away.
Using a Speedlite
You can use a Speedlite for fill-in flash. If your camera has a built-in flash unit, attaching a Speedlite activates a switch (inside the hot-shoe) that stops the built-in unit popping up. Speedlites are more powerful than built-in flash. The Speedlite 580EX, for example, has a maximum guide number of 58 (metres, ISO 100), which suggests that it can deal with subjects around 10 metres (30 feet) from the camera. Outdoors, the reach may be a little less, but still a lot further than the built-in flash.
When a Speedlite is attached and switched on, it will always fire, even if the situation is one where the camera would not automatically activate the built-in flash in full auto, portrait or close-up modes.
The most convenient camera shooting mode for fill-in flash with a Speedlite is program (P). In this mode, the flash output will automatically adjust to give a good balance between the flash illumination and the ambient light.
The output of the fill-in flash depends on the shooting conditions. With lower light levels (below about EV 10), you get a flash output just as if you were shooting a subject at the same distance indoors. Above EV 10, the flash output is gradually reduced, to a maximum of -1.5 stops (-2 stops with E-TTL autoflash) at EV 13 and above. This auto flash output reduction helps to create a better balance between the daylight and the flash illumination in bright sunlight.
Most of the shooting modes on an EOS camera can be used with fill-in flash. Here is a guide to which you should use, and why.
As mentioned on the previous pages, full auto activates the built-in flash when the camera decides that flash in needed. It does this in low light, as well as back-lit conditions. This is fine if you are just starting to use the camera, or need a quick and easy way to shoot with fill-in flash, but it offers no creative control.
This is a good mode for simple fill-in flash. As with full auto, the camera sets the shutter speed and aperture automatically, but leaves you to choose whether or not to use the flash. If you raise the built-in flash unit (either by pressing the flash button or pulling up the head, depending on the camera model), it will fire. Otherwise it won’t. Or you can attach a Speedlite and switch it on.
In both full auto and program (P) modes, the shutter speed with flash is limited to between 1/60 second and the camera’s flash synchronisation speed (between 1/90 and 1/250 second, depending on the camera). This is a fail-safe device to avoid images being ruined by the effects of camera shake at slower speeds. Most of the time you will see the lower speed being set. The higher speeds only come into use in really bright daylight. However, 1/60 second is a perfectly good speed for fill-in flash.
If you set portrait or close-up mode, the camera operates in much the same way as in full auto, though perhaps with a slightly different shutter speed/aperture combination. In landscape and sports mode, the built-in flash will never fire. You can still fire an attached Speedlite.
Shutter-priority mode (Tv)
In shutter-priority mode (Tv), you select the shutter speed and the camera automatically sets the aperture for correct daylight exposure. The camera won’t let you select a shutter speed higher than the camera’s flash synchronisation speed (if you try, it will set the synchronisation speed).
Aperture-priority mode (Av)
This is a good shooting mode for creative fill-in flash. With aperture-priority (Av), you select the aperture and leave the camera to set the shutter speed. Aperture is one of the main influences on depth-of-field (the area on either side of the focused point which appears sharp in the image).
However, you don’t have total control over the aperture. If you set a very wide aperture on a bright day, the camera may not be able to select a fast enough shutter speed for correct daylight exposure. The result will be an overexposed image. You can avoid this by checking the shutter speed value in the viewfinder before shooting. If the value is flashing, it means you are out of range and should set a smaller aperture.
If you set a very small aperture, you might find that the camera sets a slow shutter speed, especially if the sun is not shining. You should get correct exposure, but the slow speed may mean you need to use the camera on a tripod to avoid the effects of camera shake.
This allows you to set both the shutter speed and aperture independently of the camera while retaining full autoflash exposure. This is very useful for some flash techniques − but not fill-in flash. Most of the shutter speed/aperture combinations will not balance the flash with daylight. Use aperture-priority (Av) mode instead.