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DCR Workshop: Flash Demystified, Part II
by David Rasnake -  12/4/2008

In this special November/December "double issue" of DCR Workshop, we're offering up a quick tutorial for new flashgun users aimed at answering the most basic questions we field about flash shooting: how does this thing work, and how do I make my flash pictures look less like flash pictures. As a follow-up to our introduction to flash metering/control types published last week, part two of our "Flash Demystified" DCR Workshop series outlines a few basic techniques for getting more natural flash pictures using a DSLR and external flash.

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If you're a flash photography novice and you haven't checked our the first part of this two-article series, I'd recommend taking a read through the basic concepts of flash metering and modes over there before diving in here, as the information presented in last week's piece provides some important background knowledge for the techniques presented below.

With that brief introduction, let's get right down to business...


BOUNCE, BOUNCE, BOUNCE
As I noted in introducing part one of this series, if you were to mount your new flashgun to your DSLR, set everything up in TTL auto mode, and fire away, you might be surprised that the results don't really look that different from what your camera's built-in flash produces – assuming your subject is in range of the more power-limited onboard flash, of course.

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Comparison shots of our surprisingly impassive model taken with both onboard flash and a flashgun in the setup seen above show very little difference over than the discrepancy in power output.

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Onboard Flash

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External Flash

The reason why is probably obvious. Although the flash beam is emitted slightly higher relative to the lens, you're basically doing the same thing with the light in both cases. And by firing a blast of powerful illumination directly at the subject, you run up against the same potential pitfalls associated with onboard flash: red-eye, blown highlights, harsh shadows, and flat images.

The most basic solution to avoiding these issues involves using one of your flashgun's most powerful features: its ability to bounce light.

What kind of flash do I need?
As in the last section, the techniques that follow pertain specifically to most modern TTL auto flashes developed by camera manufacturers specifically for use with current bodies. While other flashes with auto or manual metering could be used with the techniques that follow, exposure will have to be compensated to make up for the light lost in reflecting the flash beam off a secondary surface.

Even more important than the metering considerations, however, is the need for, at the least, a flash with a tilting head. Most modern flashes have at least a tilting head (which allows the flash emitter to be tilted in a range from at least zero to ninety degrees).

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Better still is a more advanced flashgun that allows not only for tilt, but also for swivel.

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As we'll address momentarily, the ability to also swivel the head can be crucial when trying to bounce light in portrait-oriented shots, or when bouncing light sideways.

Many third-party flashguns and even some less expensive OEM ones, though, lack one or both of these features. While having a tilt-swivel flash head is certainly a convenience, you cam mimic most of the positioning described below by either buying a hot shoe connector cable – which allows your flash to be taken off the hot shoe (and, in turn, positioned with your left hand while shooting with right) – or by using some form of wireless flash controller (some cameras, like the Olympus system used in these demos, provide built-in wireless communication between modern bodies and flashes).

Basic Bounce
If you want to get away from the flat look of direct flash, the obvious answer involves moving the flash beam so that it's not firing directly at your subject. By bouncing the light from your flash off another object first, the beam is effectively diffused, softening its appearance, easing up those hard shadows, and providing secondary illumination that balances better with ambient indoor light. And when you're shooting indoors, the most obvious surface for bouncing your flash is the ceiling.

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The setup above demos a basic vertical bounce arrangement: I've left my tilt-swivel flash head facing forward, but tilted the beam up to 75 degrees – just shy of straight-up vertical.

Now, rather than firing at the subject, my flash beam fires upward, bounces off the ceiling, and comes back down nicely diffused – mimicking and working nicely with ambient overhead light. The result? A much softer, more natural image.

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For shooters just starting out, the best part of this kind of setup with a TTL auto flash is that, in most cases, little if any additional adjustment is needed to get a correct exposure. In theory, at least, theTTL system won't cut the flash until a sufficient exposure has been captured, meaning that the camera and flash should automatically make up for whatever light is lost to diffusion in the bounce. In practice, bounced flash often requires just a bit of positive flash exposure compensation to get things just right – evenTTL systems can get tripped up as most integrate distance-to-subject data, which doesn't take in to account that the flash beam will actually travel much farther, and lose some intensity, when bouncing. But as a rule, your default vertical bounce exposure should be within a couple of f-stops of correct right off the bat with the latest systems.

The angle of tilt on the head is another factor that adds potential complication. Although it's easy enough to work your way through the geometry involved by trial and error most of the time, 75 degrees is not an optimal angle in all situations. The reason for using a near-vertical angle is perhaps obvious: you want the light to go mostly up to avoid both the possibility for hot-spots and overshooting your subject with the beam. If you're shooting subjects that are a good distance from your lens, however, a lower angle (60 or even 45 degrees) may be needed, and if you're working with extreme close-ups, 90 degrees may be more ideal. With some experimentation, you'll quickly get a feel for where to go with your bounce angles in unusual situations.

Shooting portrait-orientation shots instead? That's where the swivel function of your tilt-swivel flash head comes in handy. The fact that the head is offset in this mode can cause some side-shadow issues, but the basic principle is the same: turn your camera to portrait orientation, swivel the head sideways so that it's pointing up at the ceiling (make sure you also return the tilt to its appropriate setting), and you're ready to shoot.

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Finally, a general reminder on bounce that applies to every example in this guide: the color of the surface you're bouncing from will alter the color of your flash beam. Hence, a white wall is ideal, as it reflects a lot of light and doesn't add strange casts. If you're working in environments with walls or ceilings in other colors (even a color as innocuous as beige, which imparts a lot of warmth) you may need to manually set your white balance, (further) adjust your exposure compensation to make up for lost light, or both.

Side Bounce
What if you want to avoid the look of direct flash, but you're in a room with an exceptionally high ceiling? Or even more so, what if you want a look that's a little more dramatic while still being soft and reasonably well-balanced? If you have a vertical wall (or, for that matter, an assistant with a piece of whiteposterboard) close at hand, you can apply the same concept of bouncing light, but move it horizontally rather than vertically.

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For landscape-orientation shots, this means shooting with your flash head swiveled in the appropriate direction (an object lesson in why heads that swivel both left and right are handy!) to hit the wall and fall back on your subject. As above, angles will vary depending on camera-to-subject distance, but a 60 or 75 degree setting is usually a good starting point.

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Photographic results using this technique show the same even, diffused light as above, but give much more directionality – and thus, visual interest – to the light you're adding as well. While it may not be ideal for every situation, side bounce is a great option to keep in mind in your mental bag of basic flash tricks.

Card Bounce
Sometimes, though, you'll run up against a situation where your space just makes any kind of bounce off a third surface impossible. Maybe you're shooting outside and want a little bit of kick to fill in shadows. Maybe you're in a room with high ceilings. Whatever the specifics of the situation, this is where the third photographer's standby – and the technique that many photojournalists rely on – comes into play.

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As the demo above suggests, what you're doing in this case is firing your flash basically straight up, and using a white card of some description to push some of this light toward your subject. The card itself can be just about anything, so long as it's small and easily attached to your flash: my Olympus flash unit came with a special attachment for this purpose, and many flashguns have a slide out white card built in, but if not, an index card and a rubber band will do the trick. At less than a dollar, this combo might just give you the most bang for your buck of any flash photography accessory (besides the flashgun itself, of course).

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The results you get from bouncing off a card have much the same look as the other bounce techniques we've seen, with perhaps a little more kick in the highlights when shooting close up. Not surprisingly, if you're trying to provide a lot of extra fill in this way, it may help to bring the angle of your flash head down from 90 degrees (again, 75 degrees – which is a set stop on most tilt-head flashguns – is a good rule of thumb). The light you'll get this way won't be as soft as pure bounce, but it's certainly vastly preferable to direct flash if you're looking to mitigate harshness and shadows.


CONCLUSIONS
As before, we've only scratched the surface of ways that you can use a flashgun to get very un-flash-like results. But these basic bounce techniques should provide an easy to follow pathway for the novice flash user to begin exploring all of the illumination possibilities that flashguns open up. As always, we're glad to provide more information, answer questions, or point you in the direction of other resources for learning about flash via our discussion forum.

Recommended Reading
Speaking of other resources, just like in the first part of this series, there are a few sources of additional information worth checking out if you're just beginning to tackle serious flash shooting. First, one commonly used technique that we didn't talk much about (excepting the discussion of bouncing light off a card) is the use of third-part light modifiers on your flash. Everyone on the web seems to have a favorite in this regard, with the venerable STO-FEN Omni-Bounce providing one of the most popular solutions to getting softer, controlled filled from a flashgun. A few months back, we published a detailed test (Light Modifiers: An Analysis and Field Guide) of several different light modifying options, and I'd recommend checking that out if you're interest in exploring diffusers or other flash accessories.

For more general information and as much depth as you could possibly want on multi-flash setups, I would also again suggest checking out David Hobby's Strobist site. One central tenet of Hobby's approach involves using studio umbrellas as a bounce surface for your flash, creating a setup that is in many ways asversatile as studio strobes but significantly more cost-effective for the amateur photographer. If you're looking for ways to expand your lighting repertoire, you'll find plenty of great ideas there.