|
|
|
At this point, I assume you're either familiar with the technical bits, or simply don't care. The more you know about flash, the easier it is to use it, but leaving that aside, the next thing we need to address is why we use flash. There are so many uses for flash and once you start using it, you're really only limited by your own creativity, the number of flash units you use and the power of them. Keeping things simple for the moment, let's just look at a single flash unit and its' uses.
Primary source of illumination
My guess is that most people use flash in this mode, most of the time. This is where the shooting situation is dark, so there's not a lot of ambient light, or certainly not enough for a useful exposure. So we use flash to light the scene and subjects.
As a fill light, reducing contrast
Another very typical use of flash is when there is a lot of contrast created by the existing available light. This can happen on very sunny days, where the part of the scene in the light is quite bright and the part in the shade is substantially darker. There is a large dynamic range in the scene and it contains a lot of contrast. In this case, we can use the flash to light the shadows and reduce contrast.
Another example of this, is where a subject maybe backlit and in silhouette against the light source. By using flash, we can illuminate the silhouette and light the subject so as it is now longer a shadow against the bright background.
This is what is referred to as fill - a secondary light source used to balance light in a scene.
Squirt/Wink flash
A small squirt of flash at minimum power is a technique commonly used in portraiture. It adds a small amount of light to the shadow regions, reducing dark shadows under the eyes and more importantly adding catch lights to the subject's eyes.
A Flash Gun - Direct Versus Bounced.
Most cameras today come with a small in built flash that sits above just above the lens. Personally, I think this flash is more or less useless with only very limited power and as its position is fixed, it offers very little in the way of creative possibilities.
In reality, if you really want to be creative with flash you'll need to buy a separate flash gun that sits into your camera's hot shoe (some people call this a hot shoe flash). Ideally this flash gun should have a head that both tilts and rotates; allowing you to bounce the flash off various surfaces rather than always having it fire directly at your subject.
Direct flash
Direct flash is what most people, without a hot shoe flash, are pretty much stuck with. The flash sits directly above the lens, in parallel to, indeed in very close proximity to, the focal plane. The result of this flash is a very harsh, unflattering, flattening light. As the flash is directed towards the subject, there will be no shadows on the subject itself, leading to it looking flat, rather than 3 dimensional. But shadows are cast and unfortunately they are cast behind the subject, which is generally unpleasing to the eye. One other disadvantage of direct flash is the horrible effect of red-eye. As the flash is more or less in line with the focal plane, the camera picks up the light hitting the back of a persons' retina, which leads to red eye.
Bounced flash
With a hot shoe flash, we can tilt the flash head upwards or indeed sideways so as to bounce the flash. This has the effect of softening the light falling on the subject that comes from the flash. Another significant advantage is that rather than having the harsh shadows behind subjects, caused by direct flash, we can now throw the shadow out of shot, below and behind the subject or indeed to the side, depending on the direction of the bouncing. One thing to note here is that the intensity of light hitting the subject has been reduced as the light now has to travel a longer distance before reaching the subject.
Diffused flash
One final trick we can do is to diffuse the light coming off the flash, by using a diffusion dome. This diffuses and softens the light even more and when used in conjunction with bounced flash, can create very soft lighting with virtually no shadows.
Previous (Technical Flash) | Next (Fill for back lighting)
|
|
|
 |
