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Photos with a built-in flash
Loved by some, derided by others, the built-in flash is now available on almost all cameras, with varying results. Lets take a look at some common settings.
Franck Mée
Updated: December 3, 2009
Updated: December 3, 2009
Red eyes
What about "red-eye reduction"? You�ll find this setting on all types of compact and it's designed to reduce or avoid reflections from the retina at the back of the eye that make human pupils red (different colours for other animals). A brief burst of flashes is fired prior to taking the photo, thus closing the iris: this means that the light from the flash no longer reaches the back of the eye and the red reflections are neutralised.
The problem is that this preflash method delays the shot by several tenths of a second, while the pupil is retracting. This may be enough to lose the moment you were trying to capture or, worse, give certain very responsive subjects enough time to change their expression between the preflash and the shot. No chance of a natural shot here then!
Users with the right software (commonly available) may well opt to disactivate red-eye reduction and sort the problem out on computer later. You�ll find specially designed red-eye filters on even the simplest photo software.
The problem is that this preflash method delays the shot by several tenths of a second, while the pupil is retracting. This may be enough to lose the moment you were trying to capture or, worse, give certain very responsive subjects enough time to change their expression between the preflash and the shot. No chance of a natural shot here then!
Users with the right software (commonly available) may well opt to disactivate red-eye reduction and sort the problem out on computer later. You�ll find specially designed red-eye filters on even the simplest photo software.
Inside or at night, the standard flash gives full frontal lighting that often blasts your subject and can create "burning" on faces.
On many compacts the only other option is to disactivate the flash. If your camera has a manual setting, dropping flash intensity may solve the problem.
In daylight, the flash can counter a backlighting effect to avoid display of a dark subject on a bright background.
Slow synch mode allows harmonisation of the flash and background so you don’t get a bright subject on a dark background.
Main light source
Basically, your flash is there to send out a brief but intense flash of light so you can take a photo when external light sources are insufficient. With improvements to the sensitivity of film, and now sensors, there’s less call for the flash: from being indispensable on a cloudy day, the flash has become merely optional on a moonlit night on the latest professional SLRs. As a main lighting source however, the flash is still very useful, especially on compacts in low lighting conditions.
Not enough light? Your flash can sort it out...
This isn’t really what we're looking for however. The results don’t correspond to what you get with the naked eye: the foreground is very bright, overly so, while the background is much darker especially the zones that are in shadow; in our example, the shadow behind the shoulder is completely black. When taking party shots moreover, your friends will no doubt soon have had enough of the rather uncomfortable flash effect…
Adjust the flash
Thankfully, you can disactivate the flash. This will give results similar to the left-hand image: dark, grainy and perhaps blurred, but which are less troublesome to your subjects.
Flash settings in the blink of an eye: succinct on the Canon G7, detailed on the Pentax K-7.
To access the flash settings, you’ll need to find the broken arrow/lightning symbol. On many compacts it’s on one of the directional buttons at the back, but you sometimes have to go into the menu (Func, Fn or Q.Menu for example). Note that on some compacts there's no flash setting in auto mode; you have to go into Programme mode to access it.
There are generally three basic modes: in auto, the camera will itself decide if you need the flash or not. In "Flash off" or "Flash Cancel" mode it doesn’t use the flash at all and in "Fill Flash;", (also called "forced;") the flash is used all the time. On pop-up flash cameras (SLR or compacts like the Ricoh GR), there's sometimes no auto mode: it’s over to you to deploy it or not.
Flash in daylight
Use fill mode when the subject is backlit, that's to say when the subject is between the camera and the light source: the front of the subject is not lit up here, a bit like a new moon. While the background will be bright (the sky for example), the subject appears like a shadow puppet, black on a light background.
Auto mode: enough light from behind the subject, the camera doesn't set the flash, giving a dark subject. Fill flash: better captured
The use of Fill mode allows you to light the foreground and obtain a more balanced result. Note that some intelligent auto modes are able to detect backlighting and activate the flash when necessary: a nice bonus.
Correcting flash intensity
Do you know when to activate the flash but find your camera still just wants to do it’s own thing? With the flash on, does it burn your subjects? This can still happen, although as auto settings become more sophisticated, it is becoming rarer. What you need to do is correct the intensity of the flash. Correcting flash exposure is very similar to correcting standard exposure (it retains the +/- logo along with the lighting symbol), but here this is simply for adjustment of the intensity of your flash. Unfortunately not all cameras have this feature.
Adjustment of flash intensity can usually be accessed easily in the menu; note that on Pentax SLRs (K-7 at bottom right), the intensity of the flash is set at the same time as the flash itself. Some compacts give a scale like the exposure scale, others a numerical value; -1 signifies a two times reduction in intesity, +1, a doubling.
Setting flash intensity at -2 (on the right) can limit unwanted reflections (left).
This setting really comes into its own however in slow synch mode, handling the compromise to be struck between added lighting and natural light.
Slow synch
Up to here, we’ve been looking at the flash as the main factor in terms of correcting exposure. In slow synch, the flash is not taken into account: it simply lends itself to one part of the image. The shutter speed isn’t calculated according to synchronisation with the flash (typically 1/200 for an SLR) but is set at low speed to correspond to the exposure time that would be needed without the flash; often several seconds.
Top, without flash: subject blurry and dark. Left, standard flash: subject bright and clear but background insufficiently lit. Right, flash in slow synch: subject brightened by flash while the background is pictured using ambient light.
With compacts, this mode can be found in the scene modes and is generally called "Night+portrait", according to its main usage: low shutter speed means you let more light in for correct exposure of a night scene, but as the subject is likely to move it won’t be correctly lit. Therefore you add the flash to illuminate the subject for a fraction of a second sometime during exposure: this freezes the subject and detaches it from the background without blocking the background off.
Another slow synch effect is the combination of the two sources of light, the short and long ones, on moving subjects. This gives one image taken with low shutter speed, giving the effect of movement, sometimes even light trails, superimposed over the flash image that is clear and frozen in space.
Some cameras offer "rear curtain sync" in which the flash is activated at the end of the exposure time rather than the start. You have to time the shot well, but the light trails then seem to follow the moving object rather than precede it.
