|Flash Photography Made Simple
by Chuck McKern
For some reason, flash photography is a topic many people are deathly afraid of and many others don't fully understand. Flash units are just tools to assist us in our picture taking. They improve our photography by allowing us to control the light. I'm going to discuss flash photography in a manner that, I hope, is easy to understand and should take some of the fear out of using that "F" word (flash not the other "F" word silly). I'll also cover several ways to use your flash to achieve better results.
When most of us think about using a flash, we think of low light scenes indoors or outside at night. Granted, a flash is important in these situations. But it will improve your photographs in other situations as well. Let's start with the simplest way to use your flash - direct flash.
Direct flash is what most people are most familiar with, and is when the flash unit emits its burst of light directly at the subject. This is common to all cameras that have a built-in flash unit from simple point and shoot cameras to consumer SLRs.
For many years, all flash attachments were designed as a direct flash (many less expensive units are still designed this way today).
The characteristics of direct flash are easy to recognize. Images have harsh shadows directly behind the subject and the photos will have little depth to them. Many photographs of people made with direct flash will have a problem with "red-eye" and if you have reflective surfaces behind your subject, such as mirrors, frames, or glass, you'll have a "hot spot" where the light is reflected off of the surface.
Some of these problems can be resolved with relative ease if you can move the flash off the camera. Moving your subject away from the background, or raising the flash and angling it to drop the shadow down behind your subject, can allow you to loose the shadow. Angling the flash will also help prevent the flash from reflecting off of mirrors or glass back into the lens.
The one advantage of the direct flash is it can reach longer distances than any other method of flash photography.
Looking at the example here, one of the first things you'll notice is the distracting, harsh shadow on the fence in the background. To capture this shot without the shadow, we should have moved our subject further away from the fence. This would have allowed the shadow to fall to the ground directly behind the model.
Whenever I tell people to use their flash outside on a bright day to improve their photographs they look at me as if I were out of my mind.
The midday sun is a very harsh light source and creates pictures that have high contrast. Highlights will be blown out and the shadows are usually deep. The brightness range from the highlights to the deep shadows will generally exceed what the film can capture. If you expose for the highlights, you'll loose your shadow detail. If you expose for the shadow detail, you will blow out your highlights.
Fill flash is used to add illumination to your foreground to help balance the light levels of your subject and the shadow areas so the film can capture both. Fill flash can also be used to brighten your subject when being lit from behind (backlight).
In our first example of the model sitting in the window, you'll notice there's a distinct shadow line across the model's chest. Without the use of a fill flash, her face would have been in a deep shadow and the front shoulder and the part of her chest that is in the sun would have been the only parts illuminated well. If we had exposed for the shadow area, the front shoulder and chest area would have been completely washed out. With the fill flash, we were able to illuminate the area in the shadow and keep from blowing out the areas in the sun. The result: we get a well-balanced, flattering look without loosing a sense of direction from the sun, even maintaining detail in her black shirt.
In the next two examples, the only light source would have been the sun coming in the window from outside. Without using the fill flash, we almost silhouette the model as the only parts being lit with natural light are the top of her right leg and back, and her right arm. Also, looking at this photograph, you will notice that the sky in the background is washed out (due to the longer exposure needed to expose the model). By introducing the fill flash, we were able to properly expose the model and still keep the sky from washing out.
One of the best way to avoid the problems of direct flash is to use a bounce flash. Bounce flashes are flash units that have the ability to angle the flash head upward in order to reflect light off of a ceiling or a reflector connected to the flash unit. This technique will give you a soft diffused light that is very flattering for portraits. Bounce will prevent "red-eye" and eliminate harsh reflections from mirrors and glass because the light is not being reflected directly back at the camera.
There are a couple of things to keep in mind when using this method of flash photography. First you will have to "pre-visualize" the angle of the light. Light will reflect at the same angle it is transmitted, so you will have to look at where the light will hit the ceiling and follow the same angle to your subject. This doesn't have to be exact, but you want to make sure the light doesn't drop down too far in front of or behind your subject.
Another important thing to remember is when bouncing off of a ceiling is you'll loose some of the reflected light, typically about two stops. If you're using a dedicated flash on a camera with TTL (Through The Lens) metering, the camera will make the correction for you. If you're using a manual flash, you will have to open your aperture by two stops to compensate for the light loss. If you're using a bounce attachment that attaches to your flash, read the documents packaged with it for the correct exposure adjustment. Again, with a TTL set-up, the camera will make the correct adjustment for you. This is all easier than it sounds once you try it.
In the examples here, notice that direct flash causes the flesh tones to wash out slightly and there is some loss of detail. In the shot with the bounce flash, The flesh tones and details are preserved. Since I was shooting outside, I used a Lumiquest Pocket Bounce to provide the reflective surface for the flash.
Front Curtain Sync
Front curtain sync is the "normal" style of flash synchronization. This means that the flash fires when the shutter first reaches its peak opening. Front sync is used whenever you want to freeze motion at the beginning of the exposure.
In our example at the beach, notice the water is suspended in mid air as it hits our model. You don't get a sense of the motion of the water.
Slow sync is when you combine flash with a slow shutter speed (normally 1/30th or slower). This will allow you to expose for low light situations and correctly expose for a subject close to you in the foreground.
If you are photographing a moving subject, with front curtain sync, the flash will record the subject at the beginning of the frame (right side) while the ambient light will allow a "ghost like" image to "streak" while moving across the frame. The result is an unrealistic image with the motion in front of your subject.
The example on the right shows a direct flash image with front curtain sync. The subject looks fine but you have no sense of the surroundings. She's just sitting in a black hole.
We took the same shot with a shutter speed of 15 seconds (requiring a tripod) using slow sync (on the right), we were able to capture the model, the fence, and the clouds in the night sky. This shot has a lot more depth and it is more comfortable to view because the model doesn't appear to be in a black hole.
In the next example notice that the car is frozen to the right side of the frame and the "streaking" caused by the lights and the ½ second exposure is in front of the car. It almost appears that the car was going backwards.
Rear Curtain Sync
Rear curtain sync fires at the end of the peak shutter opening as opposed to the beginning. When used with a slow shutter speed, you'll create a streak behind your subject and the subject frozen at the end of the frame providing a more realistic motion effect.
Compare the shot of the car to the one taken with front sync. The taillights are still blurred but now they're behind the car, giving it the sense of forward motion.
Compare the beach shot here to the previous image. You now have more of a natural feeling of motion in the water at the same exposure.
Some high-end dedicated flash units have a feature called stroboscopic flash. This mode will allow you to fire the flash rapidly, several times, during one exposure as a subject moves across the frame. Stroboscopic flash is normally used with a long exposure (usually ½ to one full second). The result is a moving subject frozen several times in the frame.
When we set up for these shots, we placed the camera ten feet away from our model and manually set our exposure at f/2.8 for ½ second. We set our flash unit to give us five bursts at 1/16 power. This allowed us to have the flash fire five times evenly spaced during the ½ second exposure. You can increase the power output to get more distance between the camera and model, but you will not be able to get as many bursts per frame. Refer to the documentation for your flash for more information on this feature.
So go out and try it! With a little experimentation you'll be using your flash like a pro.
Model: Sandi Lynne
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