Flash Photography .... when and how to use flash units.
Always remember: The power of a beam of light falls off fast!
Technically.... light falls off as the distance is squared.
This is an important consideration with smaller cameras that do not have automatic exposure control, like the two bottom cameras:
Smaller "point-and-shoot" cameras have flashes with non-automatic exposure control and very small flash units. So their range is quite limited. Usually, they are ineffective after 15-20'.
Most serious photographers use flash units with automatic exposure controls (ranging in price from $50 up to hundreds)... typical circuitry (called thyristor circuits) has the ability to continue to pour light onto the subject - and back to the camera - until the exact exposure is accomplished.....
....even if the flash is not pointed directly at the subject matter.
These strobes have a wide range of power settings to use - usually from Full power to 3/4 to 1/2 to 1/4. You can tell what aperture to use by checking the settings dial (r) or, on newer strobes, an LCD Control Panel on the back. Using Full Power drains the battery rapidly so you should normally use a lower setting. I stick with 1/2 power for most work and that is plenty. According to the dial - after I set in the film speed (f400) at the bottom I see that I need to set the sensor on the front of the strobe to red (1/2 power) .... and, RED= f8.0 .... and that is the aperture setting I would use whether I am aiming the strobe straight at the subject or not.
Here is why you would NOT point the flash directly at the subject:
If you shoot "straight- on, you run the risk of washing out skin tones, eliminating texture, creating harsh shadows, and getting "red-eye".
But, if you want to soften the light and spread it out and eliminate shadows, you should lift the flash off the camera and aim it.... I aimed the flash at the girl in the background and the light spread evenly from foreground to the back. Also, moving the flash to one side will bring out detail and texture of the subject.
Even better.... use "bounce light" whenever possible. By aiming the light upwards it will bounce off the ceiling and spread out softly, giving you much more balanced lighting and no harsh shadows.
There are times outdoors when shadows may require "fill light" from a flash. However, backlit lighting can be pleasing.... here I opened up two stops from the normal daylight exposure.
At other times, outdoors, the shadows maybe intrusive and offensive, and you should use
flash to fill in the areas of the subject that are covered with shadows.
Here I had to make the exposure based on the fact that the maximum shutter setting for flash is 1/125th ... so I
took the flash off automatic - thus giving me full power and set the aperture at f22.
Now let's take a look at some accessories designed to take the harshness out of flash photography and to help add to
your flash techniques..... most of them can be homemade at a considerable savings for those of you on a budget, or very frugal (a euphemism for cheap).
I found this nifty, and very accurate, little Vivitar flash. The trouble was that it had a fixed flash head. So I cut away the upper cover, and re-mounted the flash head inside a black, plastic film canister and secured it with two screws, so that it could swivel. I then added a portion of a translucent film canister to further diffuse the light. It is a perfect, small flash unit with sufficient power for most uses.
The flash on my trusty, old Ricoh "point-and-shoot" camera was powerful enough so I placed some Mystic tape over the flash head to reduce the harsh light.
Instead of paying $40-50 for a factory-made diffuser for my Vivitar strobe ... I cut off the end of a small plastic bottle (made of translucent material) and taped it on the head. Works great!!!!!
Finally, there are some accessories you should consider buying.... an extension cord (on the left) means you have a high degree of flexibility in the way you aim light.... and a remote sensor (right) that will make a second strobe a slave unit.