By Stokley Wilson
Fill-flash photography has always been a tricky thing. Do you remember that old saying, "Place your back to the sun when taking photographs"? This saying refers to the direction of the light falling on your subject. What this accomplished was to light your subject from the front, or front lit. This type of lighting offers the least amount of shadow, and/or contrast. This also makes your subject face into the sun.
Now most of the time we don't place our back to the sun, and now we have either a side-lit or even worse, a backlit subject. What happens with this type of light is that, in full sunshine, our subject has very bright highlight and very dark shadow area. This is where the major problem occurs. The contrast range of the scene exceeds the contrast range of the film.
Our eyes are excellent imaging tools. We look at a scene and we can see detail in the dark shadow area, as well as the bright highlight areas. The range of contrast that our eyes can see detail, in full sunlight, is about 12-16 f-stops of range. Normal films today can see detail in full sunlight of about 6 f-stops. What's even worse is if you use some of the new super-high color (contrast) films, your range of contrast that will render detail is even less.
Thus, the reason for using fill-flash is to lower the contrast range. We want to add light to the dark areas of the scene to render an image within the contrast range of the film. We also want to consider the amount of light we use when filling in the shadows. If we use the same amount of light as the highlight area, we will have the same type of light as a front lit subject. No shadow or contrast, a two dimensional look. We really want to fill in the shadow area with enough light to lower the contrast range of the subject, but still have some shadow to give us a look of depth or the third dimension.
How do we use fill-flash? It really depends on your camera system. Modern cameras are much easier to use fill-flash than older cameras. Some offer a handy feature called fill-flash with exposure compensation.
This allows you to tell the camera/flash just how much light to use without making the flash exposure equal to the mainlight exposure. Cameras without this feature are a little harder to use for fill-flash. We will break it down into two categories: Cameras with TTL flash metering, and cameras without TTL flash metering.
When using a camera without TTL flash metering, start by selecting the shutter speed. Most of the cameras without TTL flash metering will use a flash sync speed of 1/60 of a second, although some use 1/90 or even 1/125. Select the fastest possible speed for using flash with your camera. Most cameras will signify the fastest speed with either an X symbol, or a lightning bolt symbol, or just a highlighted color on the shutter speed selector. The lens opening will be determined by what film speed you use and the brightness of the light falling on your subject. If you remember the "sunny 16 rule", the highlight area of the scene exposure in full sunshine will be an aperture setting of f/16 and the shutter speed would be equal to the ISO rating of the film (100 ISO=1/125, 200 ISO=1/250 etc.). So select the highest possible shutter speed for your camera when using flash, meter the brightness of the highlight area, and then set the aperture to the f/stop for correct exposure. That is the easy part.
The flash now needs to be adjusted for fill-flash exposure. We will be using the flash in the manual mode. Flashes with variable power will be the easiest to use. What we want to accomplish is to fill the shadow area approx. one f/stop darker than our highlight area. Look at the exposure calculator on the flash. Adjust the ISO setting to a setting one f/stop more sensitive than the film speed you are actually using. 100 ISO users would set 200 ISO, 200 ISO users would set 400 ISO, etc. Then look at the calculator and find the f/stop you set in the previous step. Then calculate the distance to the subject from the information given on the flash. Most flashes will offer correct exposure at about six feet. If you use a variable power flash, you can change the power to change the subject distance. You can also use a slower shutter speed to pick up more range if you need to, but you need to be aware of camera/subject movement problems.
If your camera offers TTL flash metering, things will be a little easier for you. All you need to do is find out the exposure of the highlight area. Manually set the exposure to these settings. Then adjust the ISO setting of the camera to a rating one f/stop more sensitive than the film you are using, ISO 100=200 ISO, 200 ISO=400 ISO, etc. The flash/camera system will adjust the exposure of the flash according to the subject distance and the ambient light exposure will be set manually. Consult your camera's manual to determine if you are within the range of the flash.
If you are lucky enough to have a camera with flash exposure compensation, all you need to do is select this feature, and then adjust the exposure down about one f/stop. The camera will do all the work for you. You will need to consult your camera manual to determine if you are within the maximum range of your flash. Once you've tried this technique, try a little bit different camera setting to adjust for personal preferences.
As to the best flash for your camera, buy the most powerful flash you can afford.
- Vivitar offers the 285 Model 285HV. guide number about 120.
- Metz offers the CL-40 and CL-60 series; guide number up to 160.
- The best one offered is the Quantum Q-Flash; guide number up to 200.
These flashes are listed by size and price order with the Vivitar being the least expensive and the smallest.