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Nikon D70

The Nikon D70 is an "entry-level" SLR loaded with features at a sub-$1,000 price.

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Page 8:Flash

Review First Posted: 04/14/2004

Flash (!)
Built into the D70 is a pop-up flash unit, which operates in one of five modes: Front-Curtain Sync, Red-Eye Reduction, Red-Eye Reduction with Slow Sync, Slow Sync, and Rear-Curtain Sync. Front-Curtain Sync fires the flash at the beginning of the exposure, with every shot. Red-Eye Reduction mode pulses the very bright autofocus assist lamp before the main flash exposure, to reduce the Red-Eye Effect in shots of people. Red-Eye Reduction with Slow Sync works in a similar fashion, but combines the flash with a slower shutter speed for night portraits. (This reduces the harsh effect of nighttime flash shots, allowing more of the ambient illumination into the picture.) Slow Sync mode works with shutter speeds as slow as 30 seconds (!) to preserve color in night shots. Finally, Rear-Curtain Sync fires the flash at the end of the exposure, producing light trails behind moving subjects, rather than in front of them. In all flash modes, the flash fires with every exposure. Closing the flash disables it completely. The Flash popup button to the left of the flash doubles as a Flash Compensation button, adjusting the overall brightness of the flash from -3 to +1 EV in one-third-step increments when used in conjunction with the Sub Command dial. Pressing the Flash popup button while rotating the Main Command dial cycles through the available flash modes.

The D70's internal flash is fairly powerful, with a guide number of 11 meters or 36 feet at ISO 100. That's a bit of an odd rating, given that the minimum ISO on the D70 is 200, but so many flash units are marketed based on their guide numbers at ISO 100 that Nikon doubtless felt a guide number rating at that sensitivity level would be the most meaningful to consumers. At ISO 200, the corresponding guide number would be 15 meters or 49 feet. This means that an f/2.8 lens will give you an effective range of 17.5 feet, an impressive distance for an on-camera flash. Even with the included 18-70mm F3.5-5.6, the distance drops only to 14 feet, still reasonable. The angular coverage of the flash is enough to cover the field of view of a 20mm lens on the D70-not quite wide enough for the 18mm end of the 18-70mm zoom shipped in the kit.

One note on what appears to be an error in the D70's manual, as it relates to the built-in strobe: The manual states that the onboard flash will revert to manual-only operation with any lens that doesn't contain a CPU. (That is, for all except Nikkor D- and G-type lenses.) In actual use, I found this not to be the case, as the camera seemed to do a very good job of flash metering with any of several non-CPU autoaperture/autofocus lenses I tried it with. (Principally a old 24mm f/4 and my nice old 70-210mm f/4 zoom.) A CPU-equipped lens is certainly necessary to receive all the benefits of 3D Matrix Flash Metering (see below), but for the record, the D70 seems to do quite well with non-CPU lenses too.

Besides its slight limitation in angular coverage, my one complaint about the D70's built-in flash is that it doesn't project very far above the camera body when deployed, at least not relative to the bulk of the 18-70mm kit lens. I found that it was quite easy to get shadows on the subjects if I left the lens hood on. Even without it, with the lens at its maximum 70mm extension and with fairly closeup subjects, I found I could end up with shadows where I didn't want them. Not a huge problem, you just need to back off a little bit on the zoom and shoot with the hood removed, but I mention it to hopefully save readers some blown shots.

Also included on the D70 is an external flash hot shoe, just behind the pop-up flash compartment. The hot shoe accommodates Nikon accessory flash units, as well as a wide range of third party flashes. The full range of flash sync modes remains available for compatible flash units. Different Nikon Speedlights offer different features when used on the D70. The tables below (again used by courtesy of Nikon USA, Inc.) shows the features available when using various Nikon Speedlights with the D70. (Note that while many older flash units will work in non-TTL auto mode with the D70, but the full power of i-TTL is only available with the new SB-600 and SB-800 models. Also, note that the SB-600 and SB-800 have powerful built-in autofocus assist illuminators that take over that function when coupled with the D70. With older flash models, the D70 has to provide its own AF-assist lighting.


The D70's built-in Speedlight can also be used to control a number of SB-800 and SB-600 flashes in Commander mode for creating dramatic lighting effects. This mode does not allow for the built-in Speedlight to provide fill, however. The D70 will appear to flash, but the Commander flashes occur just before the shutter opens, to tell the other units when to fire, and what intensity to discharge at. (See the section on remote flash below, for more details.)

3D Matrix Flash Metering
The "3D" aspect of the Nikon metering system is that it uses subject distance information from the lens (only available with lenses that contain CPUs) to guide its exposure decisions. This is particularly key with flash exposures, because flash illumination falls off quite strongly as the subject gets further from the camera. With 3D Matrix Flash Metering users don't have to give a second thought to balancing the flash with ambient lighting. Just snap a few test shots to see how much fill you want, decide what level you need (for instance, -2EV). Then set that level of flash compensation, set the flash to "fill" mode, and that's it. This is really a case of technology working perfectly in the service of creativity. The camera just quietly does its job, so you can focus on composition, color, interacting with your subjects, etc. It doesn't remove the creative decisions of how you want to light your subject, it simply removes the technicalities from the equation.

Wireless Remote TTL (iTTL) Flash
The D70 brings Nikon's unique "iTTL" wireless through the lens flash metering and control first seen on the D2H down to an entry-level d-SLR. When the D2H was first introduced, the phenomenal capability of iTTL flash operation actually struck me as a being a bigger innovation than the D2H itself.

Nikon has long been known for their 3D matrix metered fill-flash capability, and the exceptional ease it brings to fill-flash exposures. With iTTL (the "i" is for "intelligent" TTL), they're further extending the capabilities of their flash technology. For the first time, iTTL makes use of the 1005-element RGB sensor used for the main exposure system, the accuracy of the metering pre-flash has been improved, and wireless capability has been dramatically expanded, with the implementation of true multi-unit, TTL wireless flash autoexposure. To me, that's the most amazing part of the new flash technology: Not just that it provides automatic flash operation without wires, but that it offers true Through The Lens (TTL) metering for flash exposures, even with multiple remote flash units: With an SB-800 speedlight as a master controller, up to three separate groups of SB-600 and SB-800 strobes can be controlled independently, each group consisting of an unlimited number of units. The D70 itself can also serve as a master controller, although it can only control one group at a time, and its internal strobe can't contribute to the exposure when it's acting as a controller. (Note though, that if you mount an SB-800 on the D70's hot shoe, the SB-800 can both act as a master controller, as well as contribute to the exposure itself.)

When I first heard about it, the whole wireless TTL system sounded like just so much magic, but it's actually pretty straightforward once you know what it's doing. (Straightforward, but no doubt requiring a lot of clever engineering.) The key to it all is strobe circuitry that can turn on and off very quickly, and fire multiple precisely timed bursts in a very short period of time. The iTTL system uses this capability in two ways. First, it uses rapid series of very brief pulses of the strobes to let the Master Controller "talk" with the various groups of remote units. The Master can command groups of remotes to fire either very brief pulses for metering, or more powerful flashes for the exposure itself. It does this by sending treating the flash head as a digital data channel, encoding commands about the type and intensity of pulse to fire in the form of rapid bursts of light.

The second way that the fast-pulse capability facilitates iTTL is by making it possible to determine exposure levels from multiple flash groups very quickly. (The speed is important, as you don't want the flash exposure determination to introduce an unacceptable shutter lag when working with multiple groups of speedlights.)

The way the iTTL system works is that the camera tells the Master controller to individually command each group of remote flashes to fire a metering pulse. Using its internal TTL sensors, the camera measures the amount of light coming from each strobe group, and integrates the light readings from all of the strobes with the ambient light coming through the lens. Via the Master controller, it then tells each strobe group how much light to emit for the exposure itself, and triggers them to fire when the shutter is opened.

If this sounds like a lot that has to go on before the shutter opens, that's because it is. It all happens very quickly though, without introducing an appreciable delay in the shutter release. (If you have several groups of strobes involved in a single exposure, and have quick enough visual reflexes, you can actually see a very brief period of flickering strobe flashes before the main exposure itself.)

The results are really pretty amazing. You can more or less scatter strobe units around the set any which way you want, and the iTTL system will deliver not only an accurate default exposure, but perfect control over the light being delivered by each group.

As noted, when the D70 is acting as a master controller, it can only control a single group of strobes, and can't itself contribute to the exposure while it's doing so. It's hard to overstate the flexibility and control this gives you though, as compared to conventional off-camera strobe systems. In particular, while it can only control a single group of strobes, there can be as many individual strobes as you like in that group.

As alluded to by the screenshot at right, the D70 actually has three separate modes in which it can control a remote flash: TTL, AA, or Manual. TTL mode works as described above, with the remote flash(es) firing a metering pre-flash, the camera reading the resulting exposure information, transmitting the needed exposure settings back to the remote unit(s), and then firing them all in synchrony.

AA mode stands for Auto Aperture, and describes the way conventional non-TTL autoexposure flash units commonly work. Based on an aperture value that you or the camera has selected, and the ISO you're currently shooting at, the camera tells the flash how much light it should be trying to produce. The flash then uses its own onboard light sensor to meter the flash itself, shutting off the flash tube once it's accumulated enough reflected light from the subject to account for a good exposure. While not as flexible as the D70's TTL metering mode, AA mode worked very well in my tests, and is in fact quite powerful in its own right. You're free to select from among a range of apertures. At ISO 200, you can use AA remote exposure mode with any aperture from f/2.8 to f/32. As sensitivity increases above ISO 200, the maximum allowable aperture decreases, decreasing one f-stop for each doubling of the ISO, until it hits f/8 at ISO 1600. (That is, you can't use AA mode to control remote flashes with apertures larger than f/8 at ISO 1600.) The manual states that AA mode is only available when using a CPU-equipped lens with the SB-800, but here again, it seemed to work quite well for me with non-CPU lenses as well.

The manual mode in the D70's remote flash control menu does just what you'd expect. It fires slaved SB-800 or SB-600 flash units at fixed power levels, with the power level selectable in one-stop increments from full power down to 1/128th power. (The external flash units have a greater range of control in manual mode than does the D70's internal strobe. The internal strobe power can only be varied from full down to 1/16 power, while the SB-800 can have its power set as low as 1/128 when operating in manual mode.)

Caught in the Act: Advanced Wireless Lighting in Action
This really has nothing to do with the D70 and SB-800's photographic capabilities, but it's a cool picture, so I thought I'd share it: Luke and I were debating how many flash pulses we thought we were seeing coming from the D70 and SB-800 in wireless TTL mode while we were measuring the shutter lag in that mode. To settle the debate, I had Luke hold the SB-800's head directly above the D70's built-in strobe. I then took another camera, pointed it at the combination, and panned it rapidly with a long exposure, just as Luke pressed the shutter. It took a few tries to catch it just right, but the shot above shows that there are actually a total of five flash pulses emitted by the D70 and SB-800 in the process of making one wireless TTL exposure. (All this happens in about 0.6 seconds.)



Here's what I think is happening in the shot above:

  1. D70 fires a "wake up" series of command pulses, to get the attention of any remotes that might be out there, lying dormant. (Note that what looks like a single bright flash here is actually a very rapid series of communication pulses, carrying digital data from the D70 to the remotes.)

  2. D70 fires a command pulse stream to instruct the remote(s) to get ready to fire a metering pulse.

  3. D70 fires a single, (low power) trigger pulse. The SB-800 fires in synchrony with it. This is the metering pulse.

    (Then there's a pause, while the D-70 digests the results of the metering pulse, and computes the correct exposure based on its TTL measurement.)

  4. The D70 fires a series of command pulses, instructing the remotes to get ready for the main exposure flash, and telling them what power level to fire at.

  5. The D70 fires a single trigger pulse. The SB-800 fires in synchrony with it. This is the main exposure flash.

Some Remote Flash Examples
OK, so all this technology sounds wonderful, but how well does it work? Without exaggerating, really, really well. The press of too-much-to-do kept me from spending more time with it, but I shot the images below to give some idea of just how big a difference off-camera flash can make, versus the limitations imposed by the on-camera strobe head. Being able to move the light source around freely really opens up what you can do with flash photography.

In these photos, I didn't try to duplicate the same shot with on/off-camera lighting, as direct comparison without variations wasn't the point. - Although the photos of Micky Mouse the Cat (his name, no wonder he's neurotic) ended up being very similarly posed and framed simply because he was willing to sit more or less still while assistant Chris and I fiddled around with the camera, flash, and soft box. (We used a Photoflex medium Movie Dome for this shot, holding the soft box and SB-800 by hand.)

D70/SB-800 remote flash examples
(Click on a thumbnail to link to the full-res image)
On-camera Remote
This is just a basic, on-camera flash shot of Charlotte the wonder dog. Blah. Typical unevenly exposed, stark, flat-looking amateur flash shot.

(These four shots were all captured with "normal" (medium) JPEG compression, so if you see any artifacts, that's why.)

Here, Chis was holding the SB-800 overhead, with the leaves from a ficus tree casting some shadows on the backdrop. (Some other shots had more interesting shadow patterns, but Charlotte wasn't posed as well. The Wonder Dog isn't that Wonderful a photo subject...)
An on-camera flash shot of Mickey Mouse the not-so-Wonder Cat. (Burdened with that name, it's probably no wonder he's as cross-tempered as he is.) This version was shot with the SB-800 held inside a Photoflex medium Movie Dome softbox, held a foot to 18 inches above Mickey. Hard to tell it's even a flash shot, the light is so even.

Onboard flash: Contributes or not?
Experimenting with these various remote modes, I initially was puzzled by the fact that the onboard flash did indeed seem to affect exposures somewhat, contrary to what the D70's manual and Nikon themselves said. After a fair bit of experimentation though, I figured out what was going on. It turned out that the shots in which I saw an exposure influence from the onboard flash were all taken at close range. After the remote units have been configured via the series of rapid communications pulses described earlier, they wait for a single (weak) strobe pulse to trigger on. The D70's trigger pulse is quite dim, but at close range (a few feet or so), it's still bright enough to have at least a small effect on the exposure. The workaround (assuming that you indeed don't want the onboard flash to make any contribution to the photo) is simply to cup your hand in front of the camera's flash head. In my experience, there was always more than enough light left spilling around my hand for the D70 to communicate with the remote SB-800, while its effect on the subject itself was all but eliminated.

SB-800 Basics (and one important note)
Since so much of the D70's exceptional remote-flash capabilities are tied to the SB-800 and SB-600 speedlights, it makes sense to include a little information about the SB-800 here. (SB-600 features are essentially the same, the primary difference being that the SB-600 can't act as a controller itself. It works as a highly-capable on-camera strobe, or a remote unit with the full capabilities of the Nikon Creative Lighting System, but can't control other flash units as a master.)

In truth, the SB-800 is really deserving of an extensive review in its own right, as there's not nearly enough room here to more than scratch the surface of its capabilities. If I can manage it (doubtful, given my perpetual review overload), I'll come back to it and do a more extensive writeup. In the meantime, here's a bare minimum of what D70 owners might like to know about the SB-800 and using it with their cameras.

The shot above shows the SB-800 perched on the stand that ships in the box with it. This is a very handy accessory for a flash that's likely to be used more often apart from the camera than mounted on it.

There's not a whole lot to see on the front of the SB-800. The flash head rotates 270 degrees horizontally, and 90 degrees vertically, letting you bounce the flash pretty much wherever you might need to when it's mounted on the camera. at the bottom of the front panel is a red-tinted window that hides the bright AF illuminator. This is a very bright red LED that's behind a diffraction grating. When enabled, it projects a crosshatched pattern whenever the camera's AF illuminator would normally trigger. Useful AF range will vary with the lens and aperture in use, but Nikon rates the range at 33 feet (10 meters) with a 50mm f/1.8 lens. Not shown in these photos is the included optional Quick Recycling Battery Pack, which attaches to the right side of the SB-800. (As viewed from the rear, on the left side in the photo above.) This is simply a small plastic compartment that attaches to the side of the SB-800, in place of its battery compartment cover. It carries an additional AA cell, boosting the total battery voltage, and reducing cycle times by about 25%. (Full-power recycle time with freshly-charged NiMH AA cells is nominally about 4.0 seconds. Adding a fifth cell in the Quick Recycling Pack drops that to about 2.9 seconds. Recycle time for less than full-power shots is proportionately faster.)

Also visible on the front of the unit is a small plastic cover that protects the external power terminals. These accommodate any of three different external power packs that Nikon sells, which provide both faster recycling (down to 2.0 seconds for full-power shots) as well as greater battery life.

Just visible on the right side of the flash (left in the photo above) is the small rubber flap that protects the external sync contacts. There are two sets of contacts here, a standard PC terminal, and a proprietary 3-terminal connector for use with Nikon's flash extension cords.

The rear of the SB-800 reveals its LCD panel and controls. At lower right is the on/off switch, with the Ready indicator light just below it. The lever that locks the strobe to the camera's hot shoe is at the bottom, and a red button labeled Flash at lower right is for test-firing the strobe. The gray button above the LCD triggers the flash in a modeling light mode, a very rapid series of strobe pulses that blend visually to produce a near-continuous illumination of the subject, so you can check lighting and shadows.

Below the LCD, a Mode button selects from among the SB-800's various operating modes. Options include TTL, Manual, Auto Aperture, Guide Number (essentially a finer-grained manual adjustment), and RPT, or repeating, in which you can program the unit to deliver a specific number of stroboscopic pulses, at rates ranging from 1 to 100 flashes per second. (The number of flashes will vary as a function of flash rate and power level. Power can be adjusted from 1/8 to 1/128 of maximum, and the number of flashes can be varied from one to as many as 90.)

At the bottom center of the rear panel, a 5-way rocker switch is used for navigating LCD menu items and manually adjusting the SB-800's zoom head. The angular coverage of the SB-800 can be adjusted to match the field of view of a 24-105 mm lens on a full-frame 35mm camera. A wide-angle diffraction lens can be pulled out from above the flash lens and flipped down over it to accommodate lenses as wide as 14mm. Pressing the center of the rocker control actuates the Set button, which confirms menu choices. Pressing and holding the Set button for more than 2 seconds calls up a hidden menu that lets you switch the flash between normal, master, and remote operation, as well as set a variety of other less-frequently accessed flash parameters such as default ISO, LCD contrast and backlight, etc.

SB-800 Menu Screens
As noted above, there's not nearly enough space or time here to go into all the SB-800's features, but the menu screens shown below will give some idea of its capabilities.

SB-800 non-wireless mode menu screens
TTL Balanced Fill-Flash (TTL BL) mode will probably be what most people use most of the time. In this mode, the camera and flash work together to try to deliver an even balance between subject and background lighting. It displays the ISO currently selected on the camera and its resulting estimate of its working range at that ISO. Also shown are an icon indicating that the attached camera supports the Creative Lighting System, and current focal length and aperture setting. Normal TTL mode is very similar to TTL BL mode, but here the emphasis is solely on the subject. Useful when you want to highlight the subject, and don't care (or may prefer) that the background is over- or underexposed.
Auto mode is the way most conventional autoexposure flash units work. In this mode, you set an aperture value on the flash itself, and the flash adjusts its exposure (as measured by its own internal sensor) to produce a good exposure with that aperture value and whatever ISO the camera is currently using. You can then manually adjust the actual exposure by varying the lens aperture. Auto Aperture mode represents a refinement on normal auto operation. In this mode, the camera tells the flash what ISO, focal length, and aperture it's using, as well as any desired flash exposure compensation, and the flash calculates the needed exposure itself, and meters it with its own built-in (that is, non-TTL) sensor. Operation in this mode is similar to that in A mode, but the flash compensates for any changes in aperture, and you instead control the exposure by adjusting the flash exposure compensation setting.
In Manual mode, neither the camera nor the flash exerts any control over the exposure. You simply tell the flash what power level to use. Options range from 1/1 (full power) to 1/128. "Distance Priority Guide Number" mode is something of a mixture of Manual mode and auto-exposure. It lets you set a fixed distance at which you want to achieve proper exposure, after which the flash will automatically adjust for variations in ISO and aperture. (The range of possible distances will of course vary directly with ISO and aperture.)
This is the SB-800's stroboscope mode. You can program it to emit rapid pulses of light at rates ranging from 1 to 100 flashes/second, with power levels ranging from 1/8 down to 1/128, and in series ranging from 1 to 90 pulses in length. (Note though, that the maximum series length will be a strong function of the power level selected, and a weaker function of the pulse rate.)

SB-800 wireless mode menu screens
Master controller:
When acting as a master controller in Nikon's Creative Lighting System, the SB-800 can independently control exposure modes and power levels for itself and three groups of remote flash units. It can also be assigned to one of four possible control channels, so as many as four different photographers can use Nikon remote flash units at the same venue without interfering with each other.

Note that in this mode, you can not only set the exposure levels of each group of remote flashes, but their operating mode as well. Options include TTL, non-TTL Auto, and Manual modes. (In the shot above, the master and Group B are running in TTL mode, with different exposure offsets, while Group A is set to Auto mode with +0.3 EV of exposure boost, and Group C is set to manual mode, at 1/64 power level.
This is the wireless mode that most D70 owners will likely use. (Unless they have multiple SB-800 units and run one as a master, attached to the camera.) Here, the only options are which channel and group you assign the flash to, and what focal length you set its zoom head to.

(NOTE that you need to assign remote strobes to channel 3, group A in order to work with the D70.)
For compatibility with older Nikon wireless flash systems, the SB-800 also supports the "SU-4" signalling system. In this mode, you can select either auto exposure, or a manual mode that lets you set the exposure of different flash units separately. (In the screen shot shown above, I've selected a power level of 1/3 stop below 1/2 power.) In this mode, there's no autoexposure option for adjusting the power of different units. I wouldn't personally find a great need for it, but you can slave together multiple SB-800 or SB-600 units, firing in strobescope mode. The same range of control over power levels, flash rate and burst length are available remotely as when the strobes are connected directly to a camera. (I can imagine this being very useful for many scientific or industrial applications, using the SB-800s for time/motion studies.)

Phew! Even that basic coverage of the SB-800's capabilities ended up taking more space than I'd intended, but it's a very impressive piece of technology, well worth its lofty price.

From the above, it's easy to see that flash photography is one area in which the D70 easily outdistances its competition. To even approach the capability offered by the D70, you'd have to spend several hundred dollars more for a wireless strobe trigger system for a competing d-SLR. And even with a wireless slave system, you'd still lack the effortless TTL flash metering the D70 provides. If you have any significant interest in flash photography, the D70 really stands alone (along with its big brother, the D2H) in the d-SLR market.


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