9
Electronic Flash with the Nikon D800/D800E
The term “professional camera” doesn’t always mean a lot, except to those who aren’t professional photographers, and who enjoy drawing distinctions among various camera categories. A real pro chooses photographic tools by what features and capabilities are needed to do a paying job. In some cases, one of the components that isn’t needed is a built-in flash. Although handy in many cases, a built-in unit, while economical (it comes “free” with the camera) has some limitations that can be easily overcome by using an external flash. That’s why Nikon’s flagship “pro” dSLRs (currently the Nikon D4) have traditionally come without any built-in flash at all. Other vendors, most notably Canon, followed suit and eschewed a built-in flash not only in their top-of-the-line cameras, but their mid-line models (such as the 5D Mark III).
Fortunately, Nikon has taken a more reasonable approach for the more compact versions of its full-frame cameras—first, the Nikon D700, and now the D800. Both include a flip-up internal flash unit, which, while certainly not a total flash solution for creative photography, does provide extra flexibility even if you elect not to carry or use an external flash unit.
Until you delve into the flash situation deeply enough, it might appear that serious photographers have a love/hate relationship with electronic flash. You’ll often hear that flash photography is less natural looking, and that the built-in flash in most cameras should never be used as the primary source of illumination because it provides a harsh, garish look.
In truth, however, the bias is against bad flash photography. Indeed, flash has become the studio light source of choice for many pro photographers, because it’s more intense (and its intensity can be varied to order by the photographer), freezes action, frees you from using a tripod (unless you want to use one to lock down a composition), and has a snappy, consistent light quality that matches daylight. (While color balance changes as the flash duration shortens, some Nikon flash units can communicate to the camera the exact white balance provided for that shot.) And even pros will cede that the built-in flash of the Nikon D800 has some important uses as an adjunct to existing light, particularly to fill in dark shadows or to serve as a wireless trigger for additional, off-camera strobes.
But electronic flash isn’t as inherently easy to use as continuous lighting. As I noted in Chapter 8, electronic flash units are more expensive, don’t show you exactly what the lighting effect will be (unless you use a second source or mode called a modeling light for a preview), and the exposure of electronic flash units is more difficult to calculate accurately.
This chapter and the next will show you how to manage all those challenges, using both the D800’s internal flash (shown in Figure 9.1) and external flash units. First, we’ll look at the basics of working with both types and then, in Chapter 10, explore the world of wireless flash photography.
Figure 9.1 One form of light that’s always available is the flip-up flash on your Nikon D800.
Electronic Flash Basics
The bursts of light we call electronic flash are produced by a flash of photons generated by an electrical charge that is accumulated in a component called a capacitor and then directed through a glass tube containing xenon gas, which absorbs the energy and emits the brief flash. For the pop-up flash built into the D800, the full burst of light lasts about 1/1,000th of a second when the unit is set to full power, and provides enough illumination to shoot a subject 10 feet away at f/4 using the ISO 100 setting. In a more typical situation you’d bump the sensitivity up to ISO 200, and use f/5.6 to f/8 and photograph something 8 to 10 feet away. As you can see, the built-in flash is somewhat limited in range; you’ll see why external flash units are often a good idea later in this chapter.
Fire When Ready!
Once the capacitor is charged, the burst of light that produces the main exposure can be initiated by a signal from the D800 that commands the internal or connected flash units to fire. External strobes can be linked to the D800 in several different ways:
Camera mounted/hardwired external dedicated flash. Units offered by Nikon or other vendors that are compatible with Nikon’s Creative Lighting System—CLS—can be clipped onto the accessory “hot” shoe on top of the camera or linked through a wired system such as the Nikon SC-28/SC-29 cables. I’ll describe CLS later in this chapter.
Wireless dedicated flash. A CLS-compatible unit can be triggered by signals produced by a pre-flash (before the main flash burst begins), which offers two-way communication between the camera and flash unit. The triggering flash can be the D800’s built-in unit, a CLS flash unit in Master mode, or a wireless non-flashing accessory, such as the Nikon RU-800, which does nothing but “talk” to the external flashes. You’ll find more on this mode in Chapter 10.
Wired, non-intelligent mode. The PC/X connector on the front of the camera (located under a rubber cover, above the 10-pin connector, as shown in Figure 9.2) is a non-intelligent camera/flash link that sends just one piece of information, one way: it tells a connected flash to fire. There is no other exchange of information between the camera and flash. The PC/X connector can be used to link the Nikon D800 with non-dedicated/non-CLS-friendly strobes, which can be studio flash units, manual non-CLS flash, flash units from other vendors that can use a PC cable, or even Nikon brand speedlights that you elect to connect to the D800 in a non-CLS, “unintelligent” mode.
Infrared/radio transmitter/receivers. Another way to link flash units to the D800 is through a wireless infrared or radio transmitter, like a Pocket Wizard, Radio Popper, or the Paul C. Buff CyberSync trigger shown in Figure 9.3. These are generally mounted on the accessory shoe of the D800, and emit a signal when the D800 sends a command to fire through the hot shoe. The simplest of these function as a wireless PC/X connector, with no other communication between the camera and flash (other than the instruction to fire). However, sophisticated units have their own built-in controls and can send additional commands to the receivers when connected to compatible flash units. I use one to adjust the power output of my Alien Bees studio flash from the camera, without the need to walk over to the flash itself.
Simple slave connection. In the days before intelligent wireless communication, the most common way to trigger off-camera, non-wired flash units was through a slave unit. These can be small external triggers connected to the remote flash (or built into the flash itself), and set off when the slave’s optical sensor detects a burst initiated by the camera itself. When it “sees” the main flash (from the D800’s built-in flash, or another flash) the slave flash units are triggered quickly enough to contribute to the same exposure. The main problem with this type of connection—other than the lack of any intelligent communication between the camera and flash—is that the slave may be fooled by any pre-flashes that are emitted by the other strobes, and fire too soon. Modern slave triggers have a special “digital” mode that ignores the pre-flash and fires only from the main flash burst.
Figure 9.2 The PC/X connector (top) can trigger flash units non-intelligently.
Figure 9.3 A wireless trigger can command external flash units to fire.
The Moment of Exposure
The D800 has a vertically traveling shutter that consists of two curtains. Just before the flash fires, the first curtain opens and moves down to the opposite side of the frame, at which point the shutter is completely open. The flash can be triggered at this point (so-called first-curtain sync), making the flash exposure. Then, after a delay that can vary from 30 seconds to 1/250th second (or faster when high-speed sync, discussed later, is used), a second curtain begins moving down the sensor plane, covering up the sensor again. If the flash is triggered just before the second curtain starts to close, then second-curtain sync is used. In both cases, though, a shutter speed of 1/250th second is the maximum that can be used to take a photo, unless you’re using the high-speed 1/320th second sync.
Figure 9.4 illustrates how this works, with a fanciful illustration of a generic shutter (your D800’s shutter does not look like this). Both curtains are tightly closed at upper left. At upper right, the first curtain begins to move downward, starting to expose a narrow slit that reveals the sensor behind the shutter. At lower left, the first curtain moves downward farther until, as you can see at lower right in the figure, the sensor is fully exposed.
Here’s a more detailed look at what happens when you take a photo using electronic flash, either the unit built into the Nikon D800 or an external flash like the Nikon SB-910, all within a few milliseconds of time. The following list assumes you are using the optical viewfinder rather than live view. The sequence is similar when using live view, except that the mirror isn’t flipping up and down as described below:
Figure 9.4 A focal plane shutter has two curtains, the lower, or first curtain, and an upper, second curtain.
1. Sync mode. After you’ve selected a shooting mode, choose the flash sync option available in that mode by holding down the Flash button and rotating the main command dial until the icon representing the choice you want is displayed in the monochrome control panel. (See Figure 9.5.) I’ll describe the sync modes later in this chapter.
2. Metering method. Choose the metering method you want, from Matrix, Center-weighted, or Spot metering.
3. Activate flash. Press the flash pop-up button to flip up the built-in flash, if necessary, or mount (or connect with a cable) an external flash and turn it on. A ready light appears in the viewfinder and on the back of an external dedicated flash when the unit is ready to take a picture.
4. Check exposure. Select a shutter speed when using Manual, Program, or Shutter-priority modes; select an aperture when using Aperture-priority and Manual exposure modes.
5. Preview lighting. If you want to preview the lighting effect, press the Depth-of-field button to produce a modeling flash burst (unless you’ve redefined this control in the Custom Settings menu as described in Chapter 12).
6. Lock flash setting (if desired). Optionally, if the main subject is located significantly off-center, you can frame so the subject is centered, lock the flash at the exposure needed to illuminate that subject, and then reframe using the composition you want. Lock the flash level using the Flash Value Lock button (which is, by default, the Fn button, but can also be assigned to the Fn, Preview, or AE-L/AF-L buttons in CSM #f4, CSM #f5, or CSM #f6). Press the FV lock button, and the flash will emit a pre-flash to determine the correct flash level, and then the D800 will lock the flash at that level until you press the FV lock button again to release it. FV lock icons appear in the monochrome control panel and the viewfinder.
7. Take photo. Press the shutter release down all the way.
8. D800 receives distance data. A D- or G-series lens now supplies focus distance to the D800.
9. Pre-flash emitted. The internal flash, if used, or external dedicated flash sends out several pulses of light. One burst can be used to control additional wireless flash units in Commander mode, while another is used to determine exposure.
10. Exposure calculated. The pre-flash bounces back and is measured by the 91,000-pixel RGB sensor in the viewfinder. It measures brightness and contrast of the image to calculate exposure. If you’re using Matrix metering, the D800 evaluates the scene to determine whether the subject may be backlit (for fill flash), a subject that requires extra ambient light exposure to balance the scene with the flash exposure, or classifies the scene in some other way. The camera to subject information as well as the degree of sharp focus of the subject matter is used to locate the subject within the frame. If you’ve selected Spot metering, only standard i-TTL (without balanced fill flash) is used.
11. Mirror up. The mirror flips up. At this point exposure and focus are locked in.
Tip
If you want to confirm that the pre-flash fires before the mirror flips up, set the D800 to Mup (Mirror Up) mode using the release mode dial. (This separates the firing of the pre-flash from the flash used to make the exposure.) Press the shutter release as you look through the viewfinder. You’ll see the pre-flash fire, and then the mirror will flip up, obscuring your view. Press the shutter release a second time to take the actual picture. Only then will the main flash fire.
12. Flash fired. At the correct triggering moment (depending on whether front or rear sync is used), the camera sends a signal to one or more flashes to start flash discharge. The flash is quenched as soon as the correct exposure has been achieved.
13. Shutter closes. The shutter closes and the mirror flips down. You’re ready to take another picture. Remember to press the FV lock button again to release the flash exposure if your next shot will use a different composition.
14. Exposure confirmed. Ordinarily, the full charge in the flash may not be required. If the flash indicator in the viewfinder blinks for about three seconds after the exposure, that means that the entire flash charge was required, and it could mean that the full charge wasn’t enough for a proper exposure. Be sure to review your image on the monitor to make sure it’s not underexposed, and, if it is, make adjustments (such as increasing the ISO setting of the D800) to remedy the situation.
Determining Exposure
Calculating the proper exposure for an electronic flash photograph is a bit more complicated than determining the settings for continuous light. The right exposure isn’t simply a function of how far away your subject is (which the camera can figure out based on the autofocus distance that’s locked in just prior to taking the picture). Various objects reflect more or less light at the same distance so, obviously, the camera needs to measure the amount of light reflected back and through the lens. Yet, as the flash itself isn’t available for measuring until it’s triggered, the D800 has nothing to measure.
The solution is to fire the flash twice. The initial shot is a monitor pre-flash that can be analyzed, then followed virtually instantaneously by a main flash (to the eye the bursts appear to be a single flash) that’s given exactly the calculated intensity needed to provide a correct exposure. As a result, the primary flash may be longer in duration for distant objects and shorter in duration for closer subjects, depending on the required intensity for exposure. This through-the-lens evaluative flash exposure system is called i-TTL (intelligent Through The Lens), and it operates whenever you use the built-in flash or have attached a Nikon dedicated flash unit to the D800.
The amount of light emitted by the flash is changed in an interesting way—interrupting the flash as the charge flows from the capacitor through the flash tube. When full power is required, either to supply the correct exposure in i-TTL mode or because you’re using the flash in Manual mode at the full power (1/1) setting, then all the energy in the capacitor flows through the flash tube. However, if less than full power is needed, the energy is stopped partway through the exposure by opening the circuit with a solid-state switch. In the olden days this was always done using a component called a thyristor, but today a component called an insulated-gate bipolar transistor, or IGBT is more common.
Because the current is interrupted before the full power of the capacitor is used, the resulting burst becomes shorter as the power output is reduced. For example, with some Nikon flash units you might see a burst lasting about 1/1,000th second at full power, but only a little longer than 1/10,000th second at 1/16th power, or 1/40,000th second at 1/128th power. This behavior is nifty when you want to freeze really fast action, such as falling water droplets—just use a lower power output level and/or work extremely close to your subject.
Because the full contents of the capacitor are not used with these partial flashes, the speedlight is able to recycle more quickly, or even use the retained energy to fire multiple times in Repeating flash mode (described later in this chapter). The only downside is that shorter flash exposures tend to take on a bluish tinge as the duration decreases. That’s because the burst starts out with a very cool color temperature and ends up much warmer at the end of the burst, averaging out to a hue that’s pretty close to daylight in color balance. When you trim off the reddish end of the flash, your resulting image may be noticeably more blue. That’s why the Flash color balance of the D800 doesn’t always produce a pleasing color rendition. You may have to fine-tune the white balance, as described in Chapter 11, or shoot RAW and correct in your image editor.
Those of you using studio flash units may be interested to know that your non-automatic strobes produce their varying power levels in a different way. With the typical studio flash, the capacitor is always fully discharged each time you take a picture, and then recharged to the level you specify for the next shot. It happens very quickly because you’re using AC power or a high-voltage battery pack instead of low-capacity alkaline or rechargeable cells.
If you set the flash for 1/2 power, the capacitor (or capacitors—studio flash may use several of them) is charged only half-filled; at 1/4 power it’s only replenished to 25 percent of its capacity. Then, when you take the photo, the full contents of the capacitor is sent through the flash tube. That’s why you need to “dump” your studio flash when you reduce the power output from a higher level. The capacitor retains the charge that was in there before, and can’t fire at the reduced capacity you want until the existing power is dumped and then replenished to the level you specify. Because of the way studio flash store and release their power, they can be designed to be more consistent at different power levels than your typical Nikon flash unit. Of course, wild color variations from flash units aren’t a huge problem, but just something you should be aware of.
So, to summarize, with CLS-compatible flash units, your automatic exposure is calculated by measuring a pre-flash and determining an appropriate exposure from that. There are other exposure modes than i-TTL available from Nikon external flash units, and I’ll get into them later in this chapter, but this section has described the process in a nutshell.
Guide Numbers
Guide numbers, usually abbreviated GN, were originally developed as a way of calculating exposure manually, but today are more useful as a measurement of the power of an electronic flash unit. A GN is usually given as a pair of numbers for both feet and meters that represent the range at ISO 100. For example, the Nikon SB-910 has a GN in i-TTL mode of 48/157 (meters/feet) at ISO 200 when using the coverage needed for a 35mm lens (the flash has a zoom head to spread/narrow the light for a range of focal lengths). To calculate the right exposure at that ISO setting, you’d divide the guide number by the distance to arrive at the appropriate f/stop.
Using the SB-910 as an example, at ISO 200 with its GN of 156, if you wanted to shoot a subject at a distance of 10 feet, you’d use f/15.6 (or, f/16). At 5 feet, an f/stop of f/32 would be used. Some quick mental calculations with the GN will give you any particular electronic flash’s range. Many years ago Nikon offered a 45mm GN lens that could couple the f/stop setting of the lens with the focus distance. You specified the guide number of the flash using a scale on the lens itself, and as you focused closer or farther away the f/stop was reduced or increased to match.
Today, guide numbers are most useful for comparing the power of various flash units, rather than actually calculating what exposure to use. You don’t need to be a math genius to see that an electronic flash with a GN in feet of, say, 157 (like the SB-910) would be a lot more powerful than the built-in flash of a camera like the Nikon D800, which has a guide number of about 55. At ISO 200, you could use f/8 instead of f/2.8 at 20 feet, an improvement of about 3.5 stops.
Choosing a Flash Sync Mode
The Nikon D800 has five flash sync modes, plus a sixth that comes into play in some circumstances, all selected by holding down the Flash button while rotating the main command dial. (See Figure 9.5 for the icons.) Those modes (which I’ve listed in logical order, so the explanation will make more sense, rather than the order in which they appear during the selection cycle) are as follows:
Front-curtain sync (available in PSAM modes). This setting, available in all exposure modes, should be your default setting. In this mode the flash fires as soon as the front curtain opens completely. The shutter then remains open for the duration of the exposure, until the rear curtain closes. If the subject is moving and ambient light levels are high enough, the movement will cause a secondary “ghost” exposure that appears in front of the flash exposure.
Rear-curtain sync (available in PSAM modes). With this setting, which can be used with Program, Shutter-priority, Aperture-priority, or Manual exposure modes, the front curtain opens completely and remains open for the duration of the exposure. Then, the flash is fired and the rear curtain closes. If the subject is moving and ambient light levels are high enough, the movement will cause a secondary “ghost” exposure that appears behind the flash exposure (trailing it). You’ll find more on “ghost” exposures next. In Program and Aperture-priority modes, the D800 will combine rear-curtain sync with slow shutter speeds (just like slow sync, discussed below) to balance ambient light with flash illumination. (It’s best to use a tripod to avoid blur at these slow shutter speeds.)
Red-eye reduction (available in PSAM modes). In this PSAM-compatible mode, there is a one-second lag after pressing the shutter release before the picture is actually taken, during which the D800’s red-eye reduction lamp lights, causing the subject’s pupils to contract (assuming they are looking at the camera), and thus reducing potential red-eye effects. Don’t use with moving subjects or when you can’t abide the delay.
Figure 9.5 Icons for flash sync modes include front sync (top left), rear sync (top middle), red-eye reduction (top right), slow sync (lower left), and slow sync with red-eye reduction (lower right).
Slow sync (available in P or A modes). This setting allows the D800 in Program and Aperture-priority modes to use shutter speeds as slow as 30 seconds with the flash to help balance a background illuminated with ambient light with your main subject, which will be lit by the electronic flash. You’ll want to use a tripod at slower shutter speeds, of course. As shown in Figure 9.6, it’s common that the ambient light will be incandescent illumination that’s much warmer than the electronic flash’s “daylight” balance, so, if you want the two sources to match, you may want to use a warming filter on the flash. That can be done with a gel if you’re using an external flash like the SB-910, or by taping an appropriate warm filter over the D800’s built-in flash. (That’s not a convenient approach, and many find the warm/cool mismatch unobjectionable and don’t bother with filtration.)
Red-eye reduction with slow sync (available in P or A modes). This mode combines slow sync with the D800’s red-eye reduction behavior when using Program or Aperture-priority modes.
Figure 9.6 I deliberately used flash and slow sync to separate this Roman sphinx sculpture (limned in bluish light from the flash) from the background illuminated by warmer incandescents.
As a reminder, note that in Shutter-priority and Manual exposure modes, you can select only the following three flash synchronization settings:
Front-curtain sync/fill flash. This setting should be your default setting. This mode is also available in Program and Aperture-priority mode, as described above, and, with high ambient light levels, can produce ghost images, discussed below.
Red-eye reduction. This mode, with its one-second lag and red-eye lamp flash, is described above.
Rear-curtain sync. As noted previously, in this sync mode, the front curtain opens completely and remains open for the duration of the exposure. Then, the flash is fired and the rear curtain closes. If the subject is moving and ambient light levels are high enough, the movement will cause that “ghost” exposure that appears to be trailing the flash exposure.
Ghost Images
The difference might not seem like much, but whether you use first-curtain sync (the default setting) or rear-curtain sync (an optional setting) can make a significant difference to your photograph if the ambient light in your scene also contributes to the image. At faster shutter speeds, particularly 1/250th second, there isn’t much time for the ambient light to register, unless it is very bright. It’s likely that the electronic flash will provide almost all the illumination, so first-curtain sync or second-curtain sync isn’t very important.
However, at slower shutter speeds, or with very bright ambient light levels, there is a significant difference, particularly if your subject is moving, or the camera isn’t steady. In any of those situations, the ambient light will register as a second image accompanying the flash exposure, and if there is movement (camera or subject), that additional image will not be in the same place as the flash exposure. It will show as a ghost image and, if the movement is significant enough, as a blurred ghost image trailing in front of or behind your subject in the direction of the movement.
As I mentioned earlier, when you’re using first-curtain sync, the flash goes off the instant the shutter opens, producing an image of the subject on the sensor. Then, the shutter remains open for an additional period (which can be from 30 seconds to 1/250th second). If your subject is moving, say, toward the right side of the frame, the ghost image produced by the ambient light will produce a blur on the right side of the original subject image. That makes it look as if your sharp (flash-produced) image is chasing the ghost (see Figure 9.7, top), which looks unnatural to those of us who grew up with lightning-fast superheroes who always left a ghost trail behind them (see Figure 9.7, bottom).
Figure 9.7 Front-curtain sync produces an image that trails in front of the flash exposure (top), while rear-curtain sync creates a more “natural looking” trail behind the flash image (bottom).
So, Nikon provides rear (second) curtain sync to remedy the situation. In that mode, the shutter opens, as before. The shutter remains open for its designated duration, and the ghost image forms. If your subject moves from the left side of the frame to the right side, the ghost will move from left to right, too. Then, about a few milliseconds before the second shutter curtain closes, the flash is triggered, producing a nice, sharp flash image ahead of the ghost image. Voilà! We have monsieur le Flash outrunning his own trailing image.
EVERY WHICH WAY, INCLUDING UP
Note that, although I describe the ghost effect in terms of subject matter that is moving left to right in a horizontally oriented composition, it can occur in any orientation, and with the subject moving in any direction. (Try photographing a falling rock, if you can, and you’ll see the same effect.) Nor are the ghost images affected by the fact that modern shutters travel vertically rather than horizontally. Secondary images are caused between the time the first curtain fully opens, and the second curtain begins to close. The direction of travel of the shutter curtains, or the direction of your subject, does not matter.
Avoiding Sync Speed Problems
Using a shutter speed faster than 1/250th second can cause problems. Triggering the electronic flash only when the shutter is completely open makes a lot of sense if you think about what’s going on. To obtain shutter speeds faster than 1/250th second, the D800 exposes only part of the sensor at one time, by starting the second curtain on its journey before the first curtain has completely opened, as shown in Figure 9.8. That effectively provides a briefer exposure as a slit of the shutter passes over the surface of the sensor. If the flash were to fire during the time when the first and second curtains partially obscured the sensor, only the slit that was actually open would be exposed.
You’d end up with only a narrow band, representing the portion of the sensor that was exposed when the picture is taken. For shutter speeds faster than 1/250th second, the second curtain begins moving before the first curtain reaches the bottom of the frame. As a result, a moving slit, the distance between the first and second curtains, exposes one portion of the sensor at a time as it moves from the top to the bottom. Figure 9.8 shows three views of our typical (but imaginary) focal plane shutter. At left is pictured the closed shutter; in the middle version you can see the first curtain has moved down about 1/4 of the distance to the top; and in the right-hand version, the second curtain has started to “chase” the first curtain across the frame toward the bottom.
If the flash is triggered while this slit is moving, only the exposed portion of the sensor will receive any illumination. You end up with a photo like the one shown in Figure 9.9. Note that a band across the bottom of the image is black. That’s a shadow of the second shutter curtain, which had started to move when the flash was triggered. Sharp-eyed readers will wonder why the black band is at the bottom of the frame rather than at the top, where the second curtain begins its journey. The answer is simple: your lens flips the image upside down and forms it on the sensor in a reversed position. You never notice that, because the camera is smart enough to show you the pixels that make up your photo in their proper orientation during picture review. But this image flip is why, if your sensor gets dirty and you detect a spot of dust in the upper half of a test photo, if cleaning manually, you need to look for the speck in the bottom half of the sensor.
Figure 9.8 A closed shutter (left); partially open shutter as the first curtain begins to move downward (middle); only part of the sensor is exposed as the slit moves (right).
Figure 9.9 If a shutter speed faster than 1/250th second is used, you can end up photographing only a portion of the image.
I generally end up with sync speed problems only when shooting in the studio, using studio flash units rather than my D800’s built-in flash or a Nikon dedicated speedlight. That’s because if you’re using either type of “smart” flash, the camera knows that a strobe is attached, and remedies any unintentional goof in shutter speed settings. If you happen to set the D800’s shutter to a faster speed in S or M mode, the camera will automatically adjust the shutter speed down to 1/250th second as soon as you flip up the flash (or prevent you from choosing a faster speed if the flash is already up). In A, or P modes, where the D800 selects the shutter speed, it will never choose a shutter speed higher than 1/250th second when using flash. In P mode, shutter speed is automatically set between 1/60th to 1/250th second when using flash.
But when using a non-dedicated flash, such as a studio unit plugged into the front flash sync terminal, the camera has no way of knowing that a flash is connected, so shutter speeds faster than 1/250th second can be set inadvertently. To avoid that problem with studio flash, I strongly recommend setting your camera to Manual exposure, and using the x250 shutter speed, which is located past the Bulb speed when rotating the main command dial all the way to the left. You won’t have to worry as much about accidentally changing the shutter speed to an unusable setting; there is no speed beyond x250th second, and if you nudge the main command dial to the right, you’ll get a Bulb exposure, which will immediately become evident.
High-Speed (FP) Sync
Note that the D800 can use a feature called high-speed sync, that allows shutter speeds faster than 1/250-1/320th second with certain external dedicated Nikon flash units. When using high-speed sync, the flash fires a continuous serious of bursts at reduced power for the entire duration of the exposure, so that the illumination is able to expose the sensor as the slit moves. HS sync is set using the controls that adjust the compatible external flash. You don’t need to make any special settings on the flash; the D800 takes care of the details for you, as I’ll describe in this section.
As I said earlier, triggering the electronic flash only when the shutter is completely open makes a lot of sense if you think about what’s going on. To obtain shutter speeds faster than 1/250th second, the D800 exposes only part of the sensor at one time, by starting the second curtain on its journey before the first curtain has completely opened. That effectively provides a briefer exposure as a slit of the shutter passes over the surface of the sensor. If the flash were to fire during the time when the first and second curtains partially obscured the sensor, only the area defined by the slit that was actually open would be exposed.
However, the D800 and certain Nikon flashes provide a partial solution, called high-speed sync or FP sync (focal plane sync). Those flash units can fire a series of flashes consecutively in rapid succession, producing the illusion of a longer continuous flash, although at reduced intensity. These multiple flashes have a duration long enough to allow exposing the area of the sensor revealed by the traveling slit as it makes its full pass. However, the reduced intensity means that your flash’s range is greatly reduced.
This technique is most useful outdoors when you need fill-in flash, but find that 1/250th second is way too slow for the f/stop you want to use. For example, at ISO 200, an outdoors exposure is likely to be 1/250th second at, say, f/14, which is perfectly fine for an ambient/balanced fill-flash exposure if you don’t mind the extreme depth-of-field offered by the small f/stop. But, what if you’d rather shoot at 1/1,600th second at f/5.6? High-speed sync will let you do that, and you probably won’t mind the reduced flash power, because you’re looking for fill flash, anyway. This sync mode offers more flexibility than, say, dropping down to ISO 100.
High-speed sync is also useful when you want to use a larger f/stop to limit the amount of depth-of-field. Select a shutter speed higher than 1/250th second, and the faster-sync speed automatically reduces the effective light of the flash, without other intervention from you.
To use Auto FP sync with units like the Nikon SB-910/SB-900, SB-700, SB-R200 units and a few discontinued speedlights like the SB-800 and SB-600, there is no setting to make on the flash itself. You need to use CSM #e1 to specify either 1/320 s (Auto FP) or 1/250 s (Auto FP). When either of those settings is activated, when using P or A exposure modes, the shutter speed will be set to 1/320th or 1/250th second (respectively) when a compatible external flash is attached. Higher shutter speeds than 1/320th or 1/250th second—all the way up to 1/8,000th second—can then be used with full synchronization, at reduced flash output. There are also situations in which you might want to set flash sync speed to less than 1/250th second, say, because you want ambient light to produce secondary ghost images in your frame. You can choose the following settings:
1/320 s (Auto FP). This setting allows using compatible external flash units with high-speed synchronization at 1/320th second or faster, and activates auto FP sync when the camera selects a shutter speed of 1/320th second or faster in programmed and Aperture-priority modes. Other flash units, including the built-in flash, will be used at speeds no faster than 1/250th second.
1/250 s (Auto FP). This similar setting allows using the named external flash units with high-speed synchronization at 1/250th second or faster, and activates auto FP sync when the camera selects a shutter speed of 1/250th second or faster in programmed and Aperture-priority modes. Other flash units, including the flip-up internal flash, will be used at speeds no faster than 1/250th second.
1/250 s. At this default setting, only shutter speeds up to 1/250th second can be used with flash, both internal and external. Note: To lock in shutter speed at 1/250th second, rotate the main control dial in M or S modes to choose the x250 setting located after the 30s and bulb speeds.
1/200 s-1/60 s. You can specify a specific shutter speed from the range of speeds 1/200th second to 1/60th second to be used as the synchronization speed for external flash units. Forcing a slower shutter speed produces a “slow sync” effect. For example, when 1/60th second has been set as the maximum flash shutter speed, ambient light is more likely to contribute to the exposure. (See Figure 9.10.) That can help balance the flash exposure with available light falling on the background (use a tripod or VR to minimize ghost images). Or, that slow shutter speed can help generate ghost images when you intentionally want them to appear in your image, say, to create a feeling of motion.
Figure 9.10 At 1/60th second, the ambient light behind the actor provided detail in the background (left). With a shutter speed of 1/250th second, the background is dark (right).
Using the Nikon D800’s Built-in Flash
The D800’s internal flash unit is part of a larger system that includes external speed-lights and other flash components. I’m referring to the Nikon Creative Lighting System (CLS), which was introduced in July, 2003 when the company unveiled the Speedlight SB-800, a flash unit compatible with early professional digital SLRs, such as the Nikon D2h/D2hs, and, within a few months, more affordable models like 2004’s Nikon D70 and all subsequent dSLRs from the company. CLS has the following features, although not all of these are supported by every Nikon camera:
i-TTL. Intelligent through-the-lens exposure control calculates exposure based on a monitor pre-flash that is fired a fraction of a second before the main burst, and then evaluated by the same RGB exposure sensor used for continuous light measurements. The system’s intelligence allows sophisticated adjustments, such as balancing the flash exposure with the ambient light exposure, say, when you shoot in full daylight, to provide fill in the shadows.
Advanced wireless lighting. A system that uses the same pre-flash concept to communicate triggering and exposure information to external flash units that aren’t physically linked to the camera, and located within a reasonable distance (say, about 30 feet). Not all Nikon cameras support AWL for their built-in flashes (and some cameras, like the D4, have no built-in flash at all). You can still use wireless lighting with such models by having a compatible external flash or trigger device serve as the “master.” Depending on whether you’re using the D800’s built-in flash or an external flash, you may be able to divide multiple flash units into up to three different “groups,” and communicate with them using your choice of any of four “channels” (to avoid having your flash units triggered by the master flash of another Nikon photographer in the vicinity). I’ll explain AWL in more detail in Chapter 10.
FV Lock. A flash value locking system that allows you to fix in place the current flash exposure so that you can, for example, measure flash exposure for a subject that is not in the center of the frame, and then reframe while using that value for subsequent exposures.
Auto FP high speed sync. Focal plane HS sync allows synchronizing an external flash while using shutter speeds faster than 1/250th or 1/320th second (with the D800; other Nikon cameras may have different maximum sync speeds of 1/200th or even 1/500th second). With a compatible flash and a camera like the D800, shutter speeds up to 1/8000th second can be used, although only a part of the flash’s illumination is used and flash range is reduced (sometimes to as little as a few feet).
Focus assist. Although Nikon cameras themselves may have focus assist illumination built-in, the CLS system allows including wide-area AF-assist illumination to be built into the front of the flash unit, or into a flash connecting cable.
Zoom coverage. Some CLS-compatible flash units have a powered zoom head built in to allow changing the area covered by the flash to match the focal length of the lens in use, as communicated by the camera to the flash itself. Zooming can also be done manually.
Flash color information communication. The exact color temperature of the light emitted by a CLS-compatible flash can vary, based on the duration of the flash burst. The flash is initially rather blue in color, and becomes redder as the burst continues. The speedlight is able to send information to the camera to allow adjusting white balance in AWB mode based on the true color information of the flash exposure.
The Nikon D800’s built-in flash has a guide number of 12/39 (meters/feet) at ISO 100 and must be activated by manually flipping it up. This flash is powerful enough to provide primary direct flash illumination when required, but can’t be angled up for diffuse bounce flash off the ceiling. It’s useful for balanced fill flash (more on that later) and for use in Commander mode, which allows the built-in flash to trigger one or more off-camera flash units in up to four separate groups wirelessly. You can use CSM #e3 to dial down the intensity of the built-in flash manually to 1/128 power so that, in Commander mode, it will activate off-camera flash units but not contribute much (if at all) to the exposure. The built-in flash can also be set to fire only as a pre-flash that will trigger external units, without setting off its main burst. The built-in flash has useful modeling light and repeating flash modes, which will be described later in this chapter.
Because the built-in flash draws its power from the D800’s battery, extensive use will reduce the power available to take pictures. For that reason alone, use of an external flash unit can be a good idea when you plan to take a lot of flash pictures. The following sections describe the basics of using the built-in flash, although many of the settings/controls also apply to external speedlights, which are discussed later in this chapter.
If you want to temporarily disable the built-in flash (and any attached external flash), a handy way to do this is to assign the Flash Off function to the Fn button, using CSM #f4, as described in Chapter 12. Then, when you press the Fn button, the built-in flash (if elevated) and any external flash attached and powered up will not fire while the Fn button is held down. This is useful if you want to temporarily disable the flash, say, to take a picture or two by available light, and then return to normal flash operation.
Using Flash Exposure Compensation
If the exposure produced by your flash isn’t satisfactory, you can manually add or subtract exposure to the flash exposure calculated by the D800. Just press the Flash button on the camera (located just below the flash pop-up button) and rotate the sub-command dial until the amount of exposure compensation you want appears on the monochrome control panel and in the viewfinder. You can make adjustments from –3EV to +1EV in 1/3 EV increments (or using some other increment, either 1/2 or 1 EV, selected by you with CSM #b3).
As with ordinary exposure compensation, the adjustment you make remains in effect until you zero it out by pressing the Flash button and rotating the sub-command dial until 0 appears on the monochrome control panel and in the viewfinder. To view the current flash exposure compensation setting, press the Flash button. When compensation is being used, an icon will be displayed in the viewfinder and on the control panel.
To change the size of the compensation increment, access Exp./Flash Comp. Step Value, Custom Setting b3 and select 1/3, 1/2, or 1 EV steps. Your change will adjust the size of the increment for both flash and ordinary exposure compensation, which I prefer. It’s always best to have your D800 use the same size “jumps” when making these exposure adjustments, which are set separately in Custom Setting b2.
Specifying Flash Shutter Speed
This is another way of specifying the shutter speed the D800 will use when working with flash. Unlike CSM #e1 described earlier, this setting determines the slowest shutter speed that is available for electronic flash synchronization when you’re not using a “slow sync” mode. When you want to avoid ghost images from a secondary exposure, you should use the highest shutter speed that will synchronize with your flash. This setting prevents programmed or Aperture-priority modes (which both select the shutter speed for you) from selecting a shutter speed that captures ambient light along with the flash.
With CSM #e2, select a value from 30 s to 1/60 s, and the D800 will avoid using speeds slower than the one you specify with electronic flash if you don’t over-ride that decision by deliberately choosing slow sync, slow rear-curtain sync, or red-eye reduction with slow sync. If you think you can hold the D800 steady, a value of 1/30 s is a good compromise; if you have shaky hands, use 1/60 s or higher. Those with extraordinarily solid grips or a lens with vibration reduction can try the 1/15 s setting. Remember that this setting only determines the slowest shutter speed that will be used, not the default shutter speed, which is set with CSM #e1.
Built-in Flash Control
Use CSM #e3 to choose one of four modes for the built-in flash. These options, which I’ll describe in more detail later, are also available for external flash units.
TTL. When the built-in flash is triggered, the D800 first fires a pre-flash and measures the light reflected back and through the lens to calculate the proper exposure when the full flash is emitted a fraction of a second later.
Manual. You can set the level of the built-in flash from full power to 1/128 power.
Repeating flash. The flash fires multiple bursts, producing an interesting stroboscopic lighting effect. When you choose repeating flash you’ll be asked to select Output (flash power level), Times (the number of times the flash is fired at the output level you specify), and Frequency (how often the flash fires per second). Note that these factors are interdependent. For example, if you tell the flash to fire at 1/8 output power, you can select from 2 to 5 flashes, at a rate of 1 to 50 flashes per second. That’s because the flash has only enough power for a maximum of 5 flashes at the 1/8 output setting. At 1/128 power, there’s enough juice for 2 to 35 individual flashes, at a rate of no more than 50 flashes per second.
Commander mode. If you never use external flash, you can safely ignore this setting. If you do, you’ll want to set up the D800 for your most frequently used options, to avoid having to fiddle with the camera if you decide to pull your SB-910 out of your bag for some impromptu multi-flash shooting. In Commander mode, the built-in flash emits pre-flashes that can be used to wirelessly control one or more remote external flash units.
Previewing Your Flash Effect
The Nikon D800’s built-in flash and compatible external units, including the SB-910, SB-700, and some earlier models, can simulate a modeling light, in the form of a set of repeated bursts of light that allow you to pre-visualize the effect the strobe will provide when fired for the main exposure. While this modeling flash, turned on or off using CSM #e4, is not a perfect substitute for a real incandescent or fluorescent modeling lamp, it does assist in seeing how your subject will be illuminated, so you can spot any potential problems with shadows.
When this feature is activated, pressing the Depth-of-field button on the D800 briefly triggers the modeling flash for your preview. Selecting Off disables the feature. You’ll generally want to leave it On, except when you anticipate using the Depth-of-field preview button for depth-of-field purposes (imagine that) and do not want the modeling flash to fire when the flash unit is charged and ready. Some external flash units, such as the SB-910, have their own modeling flash buttons.
Activating Bracketing
I discussed exposure bracketing in Chapter 4. This useful tool can also be applied to flash exposures. If you want to be able to use flash exposure bracketing in semi-automatic (Program, Shutter-priority, or Aperture-priority) modes, activate the feature using CSM #e5, where you can choose whether bracketing is used for both automatic exposure and flash (AE & flash), automatic exposure only (AE), or flash bracketing only (Flash only). Additional bracketing modes for white balance and Active D-Lighting are also available. Either of those two settings disables flash and exposure bracketing.
Bracketing is available when using Manual exposure mode, too. Configure your options using CSM #e6. If your flash is used and has been activated for bracketing, the flash will be factored in, as well. Your choices include:
Flash/Speed. With this default value, the D800 will vary the shutter speed to produce bracketed exposures and, if flash bracketing is available, will vary flash output as well. Use this option to lock your aperture set at the f/stop you choose for selective focus.
Flash/Speed/Aperture. The D800 will vary both shutter speed and aperture from your manual settings, and adjust flash output if flash bracketing is available. This setting is useful when creating a large bracket set, up to nine different exposures, because you’ll rarely want to vary shutter speed or aperture alone over such a large range of shots. The Flash/Speed/Aperture option spreads the variation over a combination of shutter speeds and apertures. You would not want to use this option for HDR photography, which works best when bracketing is accomplished only by adjusting shutter speed.
Flash/Aperture. The D800 will use the aperture to bracket your photos taken by ambient light, and if flash bracketing is available, will use flash output as well. This option is best if you’re shooting sports with manual exposure and want to lock in a specific shutter speed. As with Flash/Speed, this setting works best when the number of exposures in your bracket set is limited to 2 to 5 exposures; otherwise, the f/stop selected can vary wildly.
Flash Only. The D800 will bracket only flash exposure.
If you want to change the order in which bracketed exposures are taken (from Metered to Under to Over or Under to Metered to Over), us CSM #e7 as described in Chapter 12.
Working with Nikon Flash External Units
Nikon offers several external flash units that are compatible with CLS, ranging from the top-of-the-line SB-910 to the entry-level SB-400, and will probably introduce more speedlights during the life of this book. In addition, there are a number of older units that have been officially or unofficially discontinued, such as the SB-600, SB-800, and SB-900, which are still available, in both new and used condition. I’m going to concentrate on the current models only in the following sections, with the most emphasis on the SB-700 and SB-910 that are the most practical for owners of high-end Nikon dSLRs like the D800.
Nikon SB-400
The entry-level SB-400 (see Figure 9.11) is probably not a good choice for most Nikon D800 applications, because of its limited features and puny output. It’s built specifically for entry-level Nikon cameras like the Nikon D3200, costs around $120, and has a sparse, but easy-to-use feature set. It is a bit more powerful than the D800’s built-in flash, with an ISO 100 guide number of 21/68 at the 18mm zoom-head position. It tilts up for bounce flash to 90 degrees, with click detents at the 0, 60, 75, and 90 degree marks. Unless you feel the need for an emergency flash or fill flash unit that’s only slightly more powerful than the D800’s built-in flash, for the most flexibility, you might want to consider the next step up, the SB-700.
Nikon SB-700
This affordable (about $330) unit (see Figure 9.12) has a guide number of 28/92 (meters/feet) at ISO 100 when set to the 35mm zoom position. It has many of the top-model SB-910’s features, including zoomable flash coverage equal to the field of view of a 16-56mm lens on the D800 (24-120mm settings with a full-frame camera), and 14mm with a built-in diffuser panel. It has a built-in modeling flash feature, a wireless Commander mode, and automatic detection of DX format when mounted on non-FX camera models.
Figure 9.11 The Nikon SB-400 is an entry-level flash best suited for Nikon’s entry-level dSLRs.
Figure 9.12 The Nikon SB-700 has most features a D800 owner might want.
But the SB-700 lacks some important features found in the SB-910. Depending on how you use your speedlight, these differences may or may not be important to you. They include:
No repeating flash mode. You can’t shoot interesting stroboscopic effects with the SB-700, as you can with the D800’s built-in flash (which is less than an ideal light source in RPT mode), or the SB-910.
No accessory filters or flash diffuser dome included. You can purchase these separately, and probably should, as they are very useful. You’ll pay $30 to $50 for a set, although enterprising third parties offer substitutes for the Nikon accessories.
No port for external power pack. Using an external battery pack, like those available from Quantum and others can be important for wedding and event photographers who want to fire off a bunch of shots quickly, while avoiding frequent changes of the AA batteries the SB-700 uses. An external pack has another benefit: more exposures before the speedlight slows down to prevent overheating. External batteries don’t generate heat inside the flash as internal batteries do.
No external PC/X sync socket. This option, not found on the SB-700, is of limited use for those who want to attach an off-camera flash to the camera. The D800 has a built-in PC/X connector, so the lack of one on the SB-700 is no big deal.
Limited zoom range. The SB-700’s zoom head is limited to 24-120mm, plus 14mm with the diffuser panel. The SB-910 allows adjustments for 17-200mm focal lengths, plus 12mm with its diffuser panel. The ability to match the zoom head to the focal length you’re using can match the coverage to the field of view, so the flash’s output isn’t wasted illuminating areas that aren’t within the actual frame.
Nikon SB-R200
One oddball flash unit in the Nikon line is the SB-R200. This is a specialized wireless-only flash (see Figure 9.13) that’s especially useful for close-up photography, and is often purchased in pairs for use with the Nikon R1 and R1C1 Wireless Close-Up Speedlight systems. Its output power is low at 10/33 (meters/feet) for ISO 100 as you might expect for a unit used to photograph subjects that are often inches from the camera. It has a fixed coverage angle of 78 degrees horizontal and 60 degrees vertical, but the flash head tilts down to 60 degrees and up to 45 degrees (with detents every 15 degrees in both directions). In this case, “up” and “down” has a different meaning, because the SB-R200 can be mounted on the SX-1 Attachment Ring mounted around the lens, so the pair of flash units are on the sides and titled toward or away from the optical axis. It supports i-TTL, D-TTL, TTL (for film cameras), and Manual modes.
Figure 9.13 The Nikon SB-R200 is a wireless macro-only flash supplied with the Nikon R1 and R1C1 Wireless Close-Up Speedlight systems.
Nikon SB-910
The Nikon SB-910 is currently the flagship of the Nikon flash line up, and has a guide number of 34/111.5 (meters/feet) when the “zooming” flash head (which can be set to adjust the coverage angle of the lens) is set to the 35mm position. It has all the features of the D800’s built-in flash unit, including Commander mode, repeating flash, modeling light, and selectable power output, along with some extra capabilities.
The SB-910 is basically a slight reboot of the older SB-900, which gained a bad reputation for overheating and then shutting down after a relatively small number of consecutive exposures (as few as a dozen or so shots). The SB-910 also can overheat, but features a different thermal protection system. Instead of disabling the flash as it begins warming up, the SB-910 instead increases the recycle time between flashes, giving the unit additional time to cool a bit before the next shot. While this “improvement” is not a real fix, it does encourage you to slow your shooting pace a bit to stretch out the number of flashes this speedlight produces before it must be shut down for additional cooling.
Nikon estimates that you should be able to get 190 flashes from the SB-910 when using AA 2600 mAh rechargeable batteries, if firing the speedlight at full output once every 30 seconds, with a minimum recycling time of 2.3 seconds (which gradually becomes longer as the flash heats up and the thermal protection kicks in). To get the maximum number of shots from your batteries, Nikon figures that AF-assist illumination, power zoom, and the LCD panel illumination are switched off.
There are some improvements, such as illuminated buttons and a restyled soft case, but, in general, the SB-910 is very similar to the SB-900 that we Nikon photographers have learned to know and fear. For example, you can angle the flash and rotate it to provide bounce flash. It includes additional, non-through-the-lens exposure modes, thanks to its built-in light sensor, and can “zoom” and diffuse its coverage angle to illuminate the field of view of lenses from 12mm to 200mm on a D800 in FX mode. (In DX mode, coverage ranges from 8mm to 200mm.)
The SB-910/SB-900 also has its own powerful focus assist lamp to aid autofocus in dim lighting, and has reduced red-eye effects simply because the unit, even when attached to the D800 and not used off-camera, is mounted in a higher position that tends to eliminate reflections from the eye back to the camera lens.
Figure 9.14 shows the SB-910 fastened to the optional Nikon SC-7 bracket, and linked to the D800 through the available SC-29 cable. There are a couple advantages to this configuration. First, the side-mounting moves the flash even farther from the axis of the lens, providing additional red-eye protection. You can still tilt the flash for bounce effects. I find this set-up easier to hold, and not as awkward because you don’t have a top-heavy flash unit mounted above the camera.
But, best of all, it’s easy to uncouple the flash/SC-29 from the bracket and use both off-camera. There’s no need to fuss with wireless modes, channels, groups, or other settings; the SB-910 thinks that it’s still connected directly to the D800—which it is, of course. Another nine-foot cable, the SC-28, is available but does not have the SC-29’s built-in focus assist illuminator. I own both, but like having the SC-29’s focus-assist lamp on top of the camera, so that it is aimed at my subject should the D800 need a bit of extra illumination for focusing. Although the SB-910 has its own focus lamp, it may or may not be pointed at your subject when it comes time to use it.
I power my SB-910 with Sanyo Eneloop AA nickel metal hydride batteries, seen in Figure 9.15. These are a special type of rechargeable battery with a feature that’s ideal for electronic flash use. The Eneloop cells, unlike conventional batteries, don’t self-discharge over relative short periods of time. Once charged, they can hold onto their juice for a year or more. That means you can stuff some of these into your speedlight, along with a few spares in your camera bag, and not worry about whether the batteries have retained their power between uses. There’s nothing worse than firing up your strobe after not using it for a month, and discovering that the batteries are dead.
Figure 9.14 The Nikon SB-910 is currently the flagship of the Nikon electronic flash line up.
Figure 9.15 Sanyo’s Eneloop AA batteries are a perfect power source for Nikon speedlights.
Note that the SB-910, like your camera, contains firmware that can be updated. The custom settings readouts on the flash itself will tell you what firmware version you currently have. If an update is required, you’ll need to download the firmware module from the Nikon website. Load it onto a memory card, and then mount the flash on your D800 and power it up. You’ll find a fourth entry in the Firmware section of the Setup menu, marked S (for Speedlight or Strobe). The SB-910’s firmware can be updated through the camera/flash connection just like the camera’s own firmware. I’ll provide more information on firmware updates in Appendix D.
Light Modifiers
The SB-910 has a better array of included light modifying tools than other speedlights in the Nikon line. The standard pop-up white “card” slides out of the flash head, as shown in Figure 9.16, to bounce a little fill illumination toward your subject when the flash is tilted to bounce off a ceiling or rotated and tilted to bounce off a wall or other surface. A wide-angle diffuser also slides out and rotates to cover the front of the flash and spread the light to cover lenses with focal lengths as wide as 12mm. The included diffuser dome (see Figure 9.17) provides softer illumination for direct flash, with the SB-910 pointed at your subject, or something of a “bare bulb” effect when pointed upward. (The “bare bulb” concept dates back to film days when an electronic flash, flashbulb (!), or even an incandescent lamp was used without a reflector or shade to provide a flood of soft illumination that spread out in all directions from the source.)
Figure 9.16 The slide-out bounce card adds a kicker of light to fill in shadows or provide a catch light in the eyes of human (or others).
Figure 9.17 The included diffuser dome produces a soft, flattering light.
Figure 9.18 The SZ-2TN incandescent filter warms the flash’s illumination to match tungsten lighting.
Various filters are available for the SB-910 (and other Nikon strobes) to change the color of the light source. Two are included with the unit, the SZ-2TN incandescent filter (shown in Figure 9.18), and the SZ-2FL fluorescent filter. The SJ-3 color filter set is 20 gelatin filters in eight different colors, including blue, yellow, red, and amber. The incandescent filter is most useful, because it changes the speedlight’s illumination to match typical indoor lamps, so you can use both to light a scene without encountering a nasty mixed lighting situation. The nifty thing about the SZ-series filters is that they include a type of bar code that can be read by a sensor underneath the SB-910’s flash head, so the strobe (and your D800) “know” that a particular filter has been fitted.
Other Accessories
The SB-910 comes with the AS-21 Speedlight Stand, which lets you give the strobe a broad “foot” that can rest on any flat surface when working in wireless mode. The stand has a tripod-type socket underneath, so you can also mount the flash on a tripod or light stand without needing to purchase a special adapter.
Not included with the SB-910 are things like the WG-AS3 Water Guard, a $35 shield used when the flash is mounted on the D800, to protect the hot shoe contact from moisture or (more likely) driving rain in sports photography situations. Well-heeled photographers who shoot weddings or events and don’t already own a Quantum battery pack may be interested in the SD-9 High Performance Battery pack ($255), which holds up to eight AA batteries; or the SK-6 Power Bracket ($418) which can be outfitted with four AA batteries and provides a side-mounted handle as well as auxiliary power source.
Using Zoom Heads
External flash zoom heads can adjust themselves automatically to match lens focal lengths in use reported by the D800 to the flash unit, or you can adjust the zoom head position manually if you want to use a setting that doesn’t correspond to the automatic setting the flash will use. With older flash units, like the discontinued SB-600, automatic zoom adjustment wastes some of your flash’s power, because the flash unit assumes that the focal length reported comes from a full-frame camera. Because of the 1.5X crop factor in DX mode, the flash coverage when the flash is set to a particular focal length will be wider than is required by the D800’s cropped image.
You can manually adjust the zoom position yourself, using positions built into the flash unit that more closely correspond to your D800’s field of view when using a flash that does not, like the SB-910 and SB-900, automatically take into account the difference between FX (full-frame) and DX (APS-C) coverage. Table 9.1 shows the actual focal length of a lens (or focal length position of a zoom lens) in the left column, with the closest zoom head position on the flash unit in the right column.
To set the zoom position manually to a position of your choice (even if it doesn’t match the actual focal length in use), follow one of these steps:
SB-910. Press the Function 1 button to select the Zoom function, and then rotate the selector dial to set the zoom head position. A clockwise turn increases the value, while counterclockwise rotation decreases the zoom setting. Alternatively, you can press the Function 1 button repeatedly to increase the zoom value; it will wrap around to the widest position once you reach the maximum. To restore Power Zoom operation, press the Function 1 button to display Zoom, then press the Function 2 button. An “M” appears on the LCD above the Zoom indicator to show that the zoom setting has been made manually. An FX or DX indicator appears to the left, just above the Zoom indicator to show that the SB-910 is set for FX or DX coverage. Figure 9.19 shows the controls on the back of the SB-910 at left.
SB-900. Manually setting the zoom position is slightly different with the older SB-900 Speedlight. Press the Zoom button (located southwest of the selector dial/OK button pad) once, release it, and then rotate the selector dial until the zoom setting you want appears on the LCD. An “M” appears on the LCD above the Zoom indicator to show that the zoom setting has been made manually. An FX or DX indicator appears to the left, just above the Zoom indicator to show that the SB-900 is set for FX or DX coverage. You can also change the zoom setting by pressing the Zoom button repeatedly, in which case the focal length setting will jump from one increment to the next, wrapping around at 200mm back to the 12mm setting. Figure 9.19 shows the controls on the back of the SB-900 at right.
SB-700. Press the Zoom button to the left of the selector dial to highlight Zoom on the flash’s LCD screen. Then, rotate the control dial to the zoom position you want. Press the center OK button on the selector dial to confirm your setting. (You can also cycle through the available zoom settings by pressing the Zoom button repeatedly.) An M appears above the Zoom indicator on the LCD to show you’ve set the zoom value manually. To switch back to power zoom, press the Zoom button until the power zoom icon appears (it’s the word “zoom” with a back-looping arrow). Then press the Sel (Select) button to confirm.
SB-600. Press the Zoom button and adjust zoom position manually. M appears above Zoom in the LCD. To cancel manual zoom, press the zoom button until it matches the focal length set on the lens.
Table 9.1 Focal Length Equivalents for Zoom Heads
Figure 9.19 Flash head zoom settings can be set manually using the controls on the back of the SB-910 (left) and SB-900 (right.)
Flash Modes
The external flash units have various flash modes included, which are available or not available with different camera models, categorized into nine different groups that embrace the latest model dSLRs, some really ancient digital SLRs, and even more aged film cameras. A table showing most of the groups is included in the manuals for the external flash units, but the table is irrelevant for D800 users (unless you happen to own an older digital or film SLR, as well).
For digital cameras, there are two main groups: digital cameras not compatible with the Nikon Creative Lighting System (Nikon D1-series cameras, and the Nikon D100), and digital cameras that are compatible with CLS (including the D800). Groups I through VII, which support various combinations of features, consist of various film SLRs. You can ignore those options, unless you’re using your external flash with an older film camera.
To change flash mode with the SB-910 or SB-900, press the MODE button on the back left edge, then release it and rotate the selector dial until the mode you want appears on the LCD. The TTL automatic flash modes available for the SB-910/SB-900 are described next. (The SB-700 has a sliding mode selector switch to the left of the speed-light’s LCD with positions for TTL, Manual, and GN settings. Those are the only modes available with that flash when you’re using it as a Master. However, when the SB-700 is used as a remote flash triggered by a Master Commander flash, it can operate in Repeating mode.)
iTTL Automatic Balanced Fill Flash. In both Matrix and Center-weighted camera exposure modes, the camera and flash balance the exposure so that the main subject and background are well exposed. A TTL BL indicator appears on the LCD. However, if you switch to Spot metering, the flash switches to standard iTTL, described next.
Standard iTTL. In this mode, the exposure is set for the main subject, and the background exposure is not taken into account. A TTL indicator appears on the LCD. In either iTTL Automatic Balanced Fill Flash or Standard iTTL modes, if the full power of the flash is used, the ready light indicator on the flash and in the camera viewfinder will blink for three seconds. This is your cue that perhaps even the full power of the flash might not have been enough for proper exposure. If that’s the case, an EV indicator will display the amount of underexposure (–0.3 to –3.0 EV) on the LCD while the ready light indicator flashes.
AA: Auto Aperture flash. An A indicator next to an icon representing a lens opening/aperture is shown on the LCD when this mode is selected. The SB-910/SB-900 uses a built-in light sensor to measure the amount of flash illumination reflected back from the subject, and adjusts the output to produce an appropriate exposure based on the ISO, aperture, focal length, and flash compensation values set on the D800. This setting on the flash can be used with the D800 in Program or Aperture-priority modes.
A: Non-TTL auto flash. To work with this mode, you must set the SB-910/SB-900 for its use using the flash’s (not the camera’s) Custom Settings menu. Press the OK button in the center of the flash unit’s selector dial for about one second, and when the Custom Settings menu appears, rotate the selector dial to choose A. Press OK again, and you can choose from among four variations, Auto Aperture Flash (described above) with or without monitor pre-flash, or Non-TTL auto flash, with or without monitor pre-flash. (Note that the manual calls these options “modeling illumination” instead.) In this mode, the speedlight’s sensor measures the flash illumination reflected back from the subject, and adjusts the output to provide an appropriate exposure, without the feedback about the aperture setting of the camera that’s used with AA mode. This setting on the flash can be used when the D800 is set to Aperture-priority or Manual modes. You can use this setting to manually “bracket” exposures, as adjusting the aperture value of the lens will produce more or less exposure; the flash has no idea what aperture you’ve changed to.
GN: Distance priority manual. You enter a distance value, and the SB-910/SB-900 adjusts light output based on distance, ISO, and aperture to produce the right exposure in either Aperture-priority or Manual exposure modes. Press the MODE button on the flash and rotate the selector dial until the GN indicator appears (the GN option appears only when the flash is pointed directly ahead, or is in the downward bounce position). Then press the OK button to confirm your choice. After that, you can specify a shooting distance by pressing the Function 2 button, and then rotating the selector dial until the distance you want is indicated on the LCD. Press the OK button to confirm. The SB-910/SB-900 will indicate a recommended aperture, which you then set on the lens mounted on the D800 in Manual exposure mode.
M: Manual flash. The flash fires at a fixed output level. Press the MODE button and rotate the selector dial until M appears on the LCD panel. Press the OK button to confirm your choice. Press the Function 1 button and rotate the selector dial to dial in the power output level you want. Calculate the correct f/stop to use, either by taking a few test photos, with a flash meter, or by the seat of your pants. Then, set the D800 to Aperture-priority or Manual exposure and choose the f/stop you’ve decided on. (You can also use manual flash with the D800’s built-in unit by choosing a flash level in CSM #e3, as described in Chapter 12, and calculating the appropriate aperture.) (Good luck. I use test shots to calculate the f/stop, myself.)
RPT: Repeating flash. The flash fires repeatedly to produce a multiple flash strobing effect. To use this mode, set the D800’s exposure mode to Manual. Then set up the number of repeating flashes per frame, frequency, and flash output level, as described in Chapter 12. When using the D800’s built-in flash, use CSM #e3; with the SB-910/SB-900, press the MODE button and rotate the selector dial to display RPT. Set the flash output level with the Function 1 button and the selector dial, and choose the number of flashes with the Function 2 button and the selector dial. Finally, press Function 3 button and rotate the selector dial to choose the frequency. If you don’t have a flash meter, the best way to decide what aperture to use on the camera in repeating mode is to take a few test shots.
Repeating Flash
Repeating flash is a function that can be used with the D800’s built-in flash, as well as with external flashes like the SB-910 and SB-900. It can be used with a single flash, or in Advanced Wireless Lighting (AWL) mode, as described in Chapter 10. This section will introduce you to single-flash RPT mode.
Just follow these steps:
1. Set flash for RPT mode. You can activate either the built-in unit or your external flash. For the D800’s built-in flash, navigate to CSM #e3 and choose RPT: Repeating Flash and press OK to confirm. With the SB-910/SB-900, press the MODE button and rotate the selector dial until RPT is shown at upper left on the LCD. Then press the OK button to confirm.
2. Choose Flash Output Level. With either type of flash, you must specify the power level of the flash. That level will determine the range of the number of flashes you can expect from the capacitor’s charge. With the built-in flash, Output is selected from the left column of the Repeating Flash screen. With the SB-910/SB-900, press the Function 2 button (on the SB-910) or Function 1 button (on the SB-900) until the number of flashes is highlighted on the LCD (to the immediate right of the RPT indicator), and rotate the selector dial. Choose a power level from 1/4 to 1/128 (with the D800 built-in flash) or 1/8 to 1/128 power with the SB-910/SB-900.
3. Select number of shots. Next choose the number of shots in your series. With the built-in flash, the number is selected from the center column of the Repeating Flash screen. With the SB-910, highlight the option by pressing the Function 3 button; it’s the Function 2 button on the SB-900. The number of shots you can specify varies depending on the shutter speed and firing frequency (specified next).
4. Choose frequency: how many shots per second. This determines how quickly the series is taken. The frequency is selected from the third column of the Repeating Flash screen when using the D800’s built-in flash. With the SB-910, highlight the option by pressing the Function 3 button; it’s the Function 2 button on the SB-900.
The maximum number of shots in a series varies, depending on the shutter speed, output level, and frequency you select. The multiple flashes can be emitted only while the shutter is completely open, so a faster shutter speed limits the number of bursts that can be fired off at a given frequency. High output levels and high frequency settings both deplete the capacitor more quickly. So, the number of possible bursts will depend on the combination you choose. With the SB-910, the maximum number of shots you can expect is about 90 (at 1/64 or 1/128 power), and frequencies of from 1-3 bursts per second. That’s a large number of firings over a long period of time (30 seconds or more).
If you want very rapid bursts, expect fewer total flashes: the SB-910 will give you 24 firings at 1/128th power and 20-100 firings per second. Still, that’s quite a bit of flexibility if you think about it. You can get 24 bursts in just a bit more than one second (at the 20 Hz setting) or over five seconds (at the 100Hz setting). With the built-in flash, your options are more limited: expect 2 firings at 1/4 power, up to 35 firings at 1/128th power.
BURN OUT
When using repeating flash with the built-in flash or the SB-910/SB-900 or SB-700, or any large number of consecutive flashes in any mode (more than about 15 shots at full power), allow the flash to cool off (Nikon recommends a 10-minute time out) to avoid overheating the flash. The SB-910 increases the recycling time to extend the useful period, while both the SB-910/SB-900 and SB-700 will signal you when it’s time for a cooling-off period. The flash will actually disable itself, if necessary, to prevent damage.