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Back to Full Nikon D70 Review
Go to Nikon D70 Data Sheet
Go to Nikon D70 Pictures Page
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	*	Price breakthrough brings high-quality digital body for under $1,000.
	*	6.1 megapixel CCD, 3,008 x 2,000 pixel images
	*	ISO from 200 to 1600
	*	3 frames per second with instant power-up
	*	Part of Nikon "Total Imaging System"
	*	Compatible with >90% of all Nikon F-mount lenses ever made!

Manufacturer Overview
The new Nikon D70 is just the latest in a long line of impressive photographic tools from one of the leaders of the photo industry. Long an established leader in the film world, Nikon is a name that is immediately associated with professional and quality photography. Though immediately identifiable with professionals, they are recognized as a maker of quality cameras for consumers as well. Their pro line of film cameras includes the legendary F3, continuously produced for over 20 years now, and new legends in the making, like the F5 and F100, known for their toughness and advanced features. In the world of digital, Nikon has a commanding presence in the "prosumer" market with their Coolpix series. The Coolpix 900 broke new ground when it was introduced several years back, followed by the 2 megapixel 950, then the 3 megapixel 990. Lately they've advanced their "prosumer" line beyond what even their current SLRs offer with the 8 megapixel Coolpix 8700, with an ED glass lens and a flip out swivel screen for easy composition from many angles. They've also broadened the consumer end of their line with the recently introduced Coolpix 3200--an education in compact camera design and ease of use--and the Coolpix 3700 with its sleek, compact design, one of our favorite Coolpix designs to date. The "Nikon Total Imaging System also includes a very successful line of "Coolscan" film scanners, which we're reviewed elsewhere.

In early 1999, Nikon entered the professional digital arena with their first all-digital SLR, the D1. The 2.7 megapixel price and list price of $5,850 for the body rocked the pro camera world. Under two years later they raised the bar again with the D1x, a 5.47 megapixel camera at an even lower price point than the D1. Then last year came the D100, with a full 6.1 megapixel imager going for under $2,000, available most places now for around $1,500, body only. This offering was the first Nikon to really draw in the advanced amateur, film SLR owner who has been waiting for just such a product. Then Canon hit the street with a sub-$1,000 digital SLR with a bundled lens to meet that magical $999.99 price point that lured consumers in droves. As they did in the film arena with their N55 to N80 range of cameras, Nikon answered, this time with a camera that exceeds the capabilities of Canon's Digital Rebel. Nikon's answer, the D70, does not include a lens at the sub-$1,000 price, but it has a whole lot more features and a more solid feel than the competition. For an additional $300, users get a special 18-70mm lens (equivalent to a 27-105mm zoom on a 35mm camera), designed just for the camera's smaller sensor. Further, the new camera is compatible with almost the entire range of Nikon's F-mount AF lenses. A lower price is great, but we have to see what compromises Nikon had to make, if any, and whether those compromises will result in significantly reduced image quality over the current Nikon benchmark, the D100. Read on for our detailed analysis. (We'll give you a hint though - There are precious few compromises to be found anywhere in the D70.)

High Points

• 6.1 megapixel CCD delivering a maximum image resolution of 3008 x 2000 pixels.
• 1/500 flash sync, 1/8000 second top shutter speed.
• SLR design with true, TTL optical viewfinder.
• 1.8 inch 130,000 pixel TFT LCD with adjustable brightness.
• Polycarbonate body over a metal frame for strength with low weight.
• Interchangeable F mount lens design accommodates a wide range of Nikkor lenses, type D and type G recommended. 1.5x multiplier applies to focal length.
• Body supports both mechanically-coupled and all-electronic AF-S lenses.
• Program, Digital Vari-Program (Scene), Shutter Priority, Aperture Priority and Manual exposure modes.
• Depth of field preview button.
• TTL flash exposure metering in three modes (with the SB-800 flash).
• ISO 200 - 1600 exposure range.
• White balance has auto, six manual modes, and preset option.
• Three color modes, plus contrast, saturation, hue, and sharpness adjustments.
• Built in, five-mode popup flash; can also act as a master controller, or "commander" for SB-800 and SB-600 flashes.
• External flash hot shoe.
• Continuous shooting, Auto Exposure Bracketing, and Self-Timer modes.
• JPEG, RAW (NEF) and JPEG + RAW (NEF) file formats.
• Uses Compact Flash Type I and II, plus Hitachi Microdrive
• USB cable for computer connection
• Captures up to 3 frames per second.
• Buffer can hold up to 144 large/normal shots (actually more, in our tests), with high-speed CF cards.
• Five-area AutoFocus.
• Included CD-ROM loaded with PictureProject software.
• NTSC Video cable for connection to TV
• Battery holder that accepts 3 CR2 disposable batteries. 

Comparison with other models

Given all that's new and improved with the D70, I thought it would be helpful to readers to compare its features against those of the earlier D100, as well as against Canon's Digital Rebel and EOS-10D models. Here's the results of my poring through the spec sheets for the various cameras, as well as my own previous tests and reviews:

Executive Overview

In a bid to bring digital SLR photography into the mainstream, Nikon has introduced the D70. Looking much like a 35mm SLR, the D70 has a professional, though simplified appearance. Equipped with a 6.1 megapixel CCD, the D70 captures very high-resolution images with superb detail and excellent color. Replete with auto and manual exposure modes, the D70 is ready for whatever type of shooting its owner desires, with an instant-on feature for immediate picture-taking, and several scene modes that bias the settings for the best results in a number of common shooting situations.

Capitalizing on the broad line of Nikon optics, the D70 has a standard F lens mount that accommodates most of Nikon's 35mm lenses. This is one of the key advantages of SLR cameras: Interchangeable lenses offer greater flexibility than even high-end prosumer cameras, despite the latters' attachable accessory lenses. Use of the near-historic F mount means that a huge range of lenses originally developed for film cameras can operate on the D70, although older lens models may have quite a few limitations. 

The D70 offers several focusing options, including Manual, Single-Servo AF, and Continuous-Servo AF for moving subjects. A five point AF system can be used in three modes: Single Area, Dynamic Area, and Closest Subject. There is no analytical mode (to match Canon's "AI" mode), where the camera looks at the scene and makes decisions based on content, but Nikon chose to leave the photographer greater control over focus. In the first two modes, the user is free to pick a focus point. You can set the AF Point Lock switch to L to keep the focus point set indefinitely at the location you've chosen. Switch it to the dot, and it can be changed, but again only in Single Area and Dynamic Area modes. The user uses the MultiSelector nav disk on the back to move the focus point around in the viewfinder.

The D70 features a true TTL (through the lens) optical viewfinder, complete with information display along the bottom. This shows shutter speed, exposure compensation, flash status, focus point and mode, focus lock, and flash status among others.

The five focus areas are marked by round-edged rectangles that overlay the image. Whether chosen by the user or the camera, the active focus area is highlighted in red when focus lock is achieved under dim lighting, or turns black if the light in the frame is brighter. In either condition, the focus indication can be lost in the details. A brighter light would be better. Custom setting 8 activates an optional Grid Display, useful for matching to the horizon line in landscape shots, walls and floors in architectural shots, or when using a tilt or shift lens.

A diopter correction slider next to the viewfinder can be adjusted from -1.6 to +0.5 to accommodate eyeglass wearers; optional corrective lenses are available that extend the range from -5 to +3.

As is the case with most digital SLRs, the D70's LCD monitor is solely for viewing captured images and displaying the menu system, not for framing shots. (I'm careful to mention this for those potential users accustomed to composing pictures in point-and-shoot rangefinder-style digital cameras, who are considering moving up to a more capable camera.) Also important to know is that digital SLR cameras capture only stills, not video or audio.

In playback mode seven information screens are available, giving a great deal of detail, plus a histogram and highlight displays. The highlight display shows any blown-out highlights, flashing the overexposed areas from white to black. This is something we'd like to see on all digital cameras, including consumer models, to let you know when portions of a photo have been overexposed. 

Because this is meant as a consumer SLR, Nikon has added quite a few Scene modes in addition to the usual Program, Aperture Priority, Shutter Priority, and Manual exposure modes that appeared on the D100. The D70 has a full Auto mode for point-and-shoot convenience, as well as Portrait, Landscape, Close Up, Sports, Night Landscape, and Night Portrait. All are quickly selected from the Mode Dial, which turns left or right with no limiter built in. In other words, you can turn toward the icon you want, no matter where you are on the dial, and not worry about whether you're going to run into a limiter, as we see on Canon's competing Digital Rebel model. A minor point perhaps, but one that makes mode selection that much faster.

In Program mode, where most intermediate photographers will probably spend a lot of time, rotating the Main command dial adjusts through the possible combinations of aperture and shutter speed while maintaining proper exposure. This allows the user to decide dynamically whether they want to emphasize depth of field or speed of capture based on the scene. It is not available in full Auto mode, or in any of the Scene modes. 

Using a combined mechanical and CCD electronic shutter, the D70 is able to achieve speeds from 30 seconds to 1/8000 second. This is twice the maximum speed of its brother the D100. In manual mode, Bulb is also available, up to a maximum of 30 minutes. Bulb exposures can also be controlled via remote, an important feature for blur-free long exposures. The shutter opens two seconds after the remote is activated, and doesn't shut until the remote is activated again, or the 30 minute maximum exposure time ends.

Nikon's trademark D color matrix metering is available by default when using G or D type lenses. It's considered "3D" because it gathers distance information from the lens to further optimize the meter's effectiveness. Inherited from the Nikon D2H and F5 is the very high resolution of this 3D matrix metering system. The Canon Digital Rebel has a 35 zone matrix meter, and the Nikon D100 has a 10 zone matrix meter, but the D70 has a 1,005 pixel metering sensor, separate from the main image sensor, that covers the entire frame. (Very impressive.) Matrix metering is useful for backlit subjects or when very dark subjects occupy a significant portion of the frame. Center Weighted metering is also available, which measures light from the entire frame, but places the greatest emphasis on a circular area in the center. Spot metering takes a reading from dead center of the image, best when using the AE lock function, because it lets you meter off of a face or other area of primary importance and then recompose. The spot meter on the D70 bases its reading on approximately 1% of the total frame area, providing very precise exposure determination. These latter two metering options are only available in the Program, Shutter, Aperture, and Manual modes; the camera defaults to Matrix in the full Auto and Scene modes.

Sensitivity settings range from ISO 200 to 1600. In testing, we found even ISO 1600 produced entirely acceptable results, with noise levels that were low, if not negligible. A special noise reduction mode can reduce noise in longer exposures with shutter speeds slower than about one second. When Noise Reduction is active, the time to process each image more than doubles, and "Job NR" blinks across the top of the status LCD while the processing is taking place. Surprisingly, my tests showed that having NR active also slowed continuous exposures even in bright lighting, regardless of the shutter speed being used. - This despite the fact that the NR processing is only supposed to apply to very long exposures. The amount of space in the buffer also decreases with NR on.

In Program, Shutter, Aperture, and Manual modes, exposure can be adjusted between -5 and +5 EV in increments of 1/3 EV. The camera can also be set to adjust EV in 1/2 EV increments, if you prefer. EV adjustment values show on the Status LCD only when the EV adjustment button is pressed, though in the viewfinder the scale is skewed on the exposure readout any time an exposure compensation has been specified. Exposure compensation can be immediately reset to 0--along with all other custom settings--via a two-button combination, both marked by a green dot next to both the Bracket and Exposure mode buttons. Hold these buttons down for more than two seconds and all settings are returned to default (see button listings later in this review to see which functions are reset by this process). This is a handy feature that I'd also like to see on other cameras, as it can be tedious resetting a large number of camera settings manually. 

Auto Bracketing can help you with EV adjustments of up to plus or minus 2 EV. The camera will take one shot underexposed by the amount you set, one at the "metered exposure" (determined by the camera in Program, Shutter, and Aperture mode; by the user in Manual mode), and one overexposed. The sequence can also be "metered," under, over. Three presses on the shutter are required to complete each bracketing sequence. The sequence can also be applied to flash exposures, and white balance settings. (White Balance Bracketing can only be done in JPEG mode.) In the case of White Balance, Auto Bracketing works a little differently. Instead of requiring three presses on the shutter to complete the sequence, only one press is required to produce the desired number of frames. Users choose between two and three frames and which direction they want to go. A little experimentation is required, as is a thorough read of the manual. The benefits of using this feature could be significant, however, when you're just not sure about the white balance settings and the shot is critical. 

White balance can be left in Auto, where the camera will adjust the color temperature from 3,500 to 8,000 Kelvin using both the 1,005 pixel RGB exposure sensor and the CCD image sensor. This is a wider range than the D100's Auto White balance mode offers (but I'd still really like to see it extend lower, to handle the incandescent lighting so common in US interior spaces), though both offer the same preset options, from Incandescent (3,000K) through Fluorescent (4,200K), Sunlight (5,200K), Flash (5,400K), Cloudy (6,000K), and Shade (8,000K). You can also preset a white balance by pointing the camera at a white or gray object, or it can be copied from an existing photograph. You can fine-tune the color balance of all white balance settings (except Preset) from -3 to +3 arbitrary units, for a more precise color balance. The D70 also offers Hue, Tone, and Sharpness adjustments. Tone curves can be set to Auto or set from Normal (0 adjustment) to Low Contrast (-2), Medium Low (-1), Medium High (+1), High Contrast (+2), and Custom. Custom allows the user to download a custom tone curve created in Nikon Capture 4 on a PC. 

There are three color modes, two of them sRGB, and one Adobe RGB. The first sRGB (mode Ia) is optimized for skin tones, and is the default setting. The second setting is Adobe RGB (mode II), offering a wider gamut than sRGB, meaning that it can capture and deliver more colors to a program like Photoshop, especially in the green range. It is recommended for photos that will be modified extensively on a computer. The second sRGB (mode IIIa) is optimized for landscape shots, and apparently more closely approximates the color space of the previous D100. 

In more than a few ways, the D70 is actually superior to its higher priced predecessor, and one of those is its continuous capture mode. It's not only faster at 3 frames per second compared to the D100's 2.5 fps, it also can capture far more frames without pausing. When using a fast Compact Flash card, like a SanDisk Ultra II (or presumably Lexar's forthcoming 80x cards, when they're available in another month or so), the buffer doesn't fill very quickly. One can watch the counter move down to about a five-frame capacity and slowly move down then back up. The faster the card, the more quickly the new buffer can offload the data, and in the case of high resolution images saved with the "normal" JPEG compression setting, the buffer may never fill at all. This is truly amazing, and a first with any digital camera we've seen. (Although forum poster RobN reminded Dave that the Kyocera/Contax "R" series of consumer cameras have this ability also. - But the D70 is indeed the first d-SLR that can do this. - Thanks Rob!) This effect requires a card with a speed rating of 60x or more.

The D70's built-in pop-up flash has an ISO 200 Guide Number of 15m/49ft (ISO 100 Guide Number would be 11/36; though the D70's ISO starts at 200, so this is only stated for comparison with other cameras and flash units). When a CPU lens is on the camera, Nikon's i-TTL is invoked, allowing complex measurements via low-power "almost invisible" preflashes right before the main flash, that the camera combines with distance information from the lens' CPU. This is excellent for fill flash, because the D70 uses its 1,005 segment Matrix meter to balance foreground lighting against backlighting. When a non-CPU lens is used, the built-in Speedlight supposedly only works in Manual mode, but my test unit showed no difference in flash behavior when I tried it with a couple of my older lenses.

Flash sync modes include Front-curtain sync, Red-eye reduction, Slow sync, Slow sync with red eye reduction, Rear- and Slow rear-curtain sync. In full Auto, Portrait, and Macro modes, Auto front curtain sync, Auto with red eye, and Off are the only options. In Night Capture mode, both Auto flash modes are of necessity Slow sync. Flash Exposure Compensation allows the user to adjust brightness from -3 to +1 EV, providing for very subtle fill-flash effects. 

The D70 uses Type I and Type II CF cards and MicroDrives. In addition to three JPEG compression levels, images can also be saved as NEF-format compressed RAW images, or simultaneously as RAW + JPEG files. Resolutions are 3,008 x 2,000, 2,240 x 1,488, and 1,504 x 1,000. When printed at 200 dpi, these can produce images as big as 15 x 10, 11 x 7.5, and 7.5 x 5 inches, respectively. A USB cable comes with the camera for uploads, as well as Nikon PictureProject software and a 30-day free trial of Nikon Capture. A video cable appropriate for the market (NTSC or PAL) is also included. 

One EN-EL3 Lithium Ion battery pack powers the D70, providing 7.4V at 1400mAh. Though the battery looks very much like the Canon BP-511, they're not compatible. The EN-EL gives very long run times in the D70, but unfortunately there is no battery pack/vertical grip planned for the camera, an advantage that both the D100 and Digital Rebel have. The battery door does not appear to be removable, and there also appear to be no controller contacts inside the battery compartment or camera bottom that would allow shutter and sub-command dial functions to pass through, only two battery contacts. (So don't hold your breath for a vertical grip to be announced later.)

Offering a 6.1 megapixel imager with beautiful tone and color as well as excellent resolution, a sturdy, competent build, capable of fast capture, and bundled with a very nice lens, all at an affordable price, the D70 is poised to be Nikon's next big hit. This is an amazingly capable camera, with excellent image quality and excellent optics, at a very affordable price. While more expensive than the Canon Digital Rebel, the D70 more than justifies its slight price premium with a plethora of enhanced features.

Design

Taking design cues from both the D100 and D2H, the Nikon D70 is simpler in appearance and smaller size than either. It is nonetheless quite attractive, built of a black polycarbonate body with red, silver, and gray accents. Anyone familiar with Nikon's film or digital cameras will appreciate the similarity of most controls on the D70. The body's plastic body shell and smaller size are responsible for its low weight of 21 ounces, or 595 grams stripped of battery, lens, body cap, and monitor cover. With the battery installed, it weighs in at 28.3 ounces (683 grams), while fully loaded with the battery, a memory card, and the 18-70mm lens shipped with the "bundle," it weighs 39 ounces (1106 grams).

The D70 feels great to hold. The grip and much of the body has a soft rubbery texture and the front grip itself is excellent. The sculpted CF door on the back serves as a great thumb hold, working well against the sharp angle on the front grip to provide a secure one-handed hold. With the 18-70mm lens attached, balance is superb. The handgrip is also long, allowing room for most users' pinkies to rest comfortably with room to spare. The index finger finds the shutter and power switch naturally, but the sub-command dial is a little low for my tastes. All that room I talked about for the pinkie is taken away as the index finger searches for the dial. I suppose the middle finger could stand in for the index finger when controlling the command dial, but that would significantly weaken your grip on the camera in the process.

The metal F-style lens mount is the D70's prominent feature, and certainly its most valuable, offering compatibility with a massive array of quality Nikkor lenses. A D-shaped button just left of the lens serves to release the lens lock. (All directions are noted as if reader were holding the camera face out.) Below this a switch facing off to the left chooses between AF and Manual focus modes. Above the lens release button is the flash pop-up button. Down and to the right is the Depth of Field Preview button. The AF assist light is above that, mounted almost flush with the camera's tumble-home taper. The Sub-command dial is also visible from here, right above the D70's triangular red accent.

The right side of the camera has only the neck strap eyelet and a few screws to speak of. Despite its jutting angle, the eyelet does not jab into your hand at all.

The left side of the D70 has the other neckstrap eyelet and a rubber door covering DC in and Video Out ports. A separate rubber door covers the USB port; having this down low allows for fewer snags when uploading photos, as it keeps the cable close to whatever surface you have the camera resting on. Here you also get a better look at the AF/Manual focus selector switch and the Flash pop-up button.

On top we see the pop-up flash and hot shoe, both in-line with the lens. To the right of the flash gear is the Status LCD. Most of what's available through the viewfinder is available here, plus a few extras. Many features can be set here via button/dial combinations without having to enter the main menu, an excellent benefit as you become more familiar with the camera. Here we also have the shutter button, surrounded by the power switch. The Metering mode button is just behind that, and next to it is the exposure compensation button. The screen illumination button is just right of the status LCD. Both the Screen illumination button and the Metering mode button can be used in combination with the Continuous mode and Bracket buttons to either Format the CF card or Reset the device's settings to default when held down simultaneously for more than two seconds. (To finalize the Reset, you have to release and press these buttons a second time.) Left of the flash is the mode dial, which can be turned in any direction, without limit.

From the back we see a slightly more attractive arrangement of components, when compared to the D100. I found these to be just slightly more consumer friendly in appearance, whereas they're still mostly in the same places for pros who would choose the D70 as a secondary or tertiary camera. Eyeglass wearers will appreciate the reasonable standoff of the viewfinder, as well as its rubber bumper. A sliding diopter correction control is nestled to the right of the viewfinder. Just left of center is the 1.8 inch LCD that comes with a protective plastic cover to prevent scratches to the LCD (I find this a little annoying since my breath too often fogs the cover on the inside, and I cannot wipe it without removing the cover, so I end up keeping the cover in the bag). Upper left of the LCD is the Bracket button, which works in conjunction with the Main command dial on the right. The Continuous capture mode button is just right of the Bracket button. Down the left side of the screen are the Playback button, Menu button, ISO/Thumbnail button, White Balance/Protect/Help button, and Image Quality/Size/Enter/Zoom button. These last three buttons have integrated functions that on the D100 appear on the Mode dial. Their presence here adds a little unnecessary complexity, but it also keeps truer to Nikon's Shot Priority philosophy. With items like ISO on the Mode dial, one couldn't just press the shutter button to enter capture mode, a major hindrance that I noted in my review of the D100. 

Above right of the screen is the Auto Exposure/Auto Focus Lock button. Below that is the Multi selector navigator, then the focus point lock switch and the delete button. Finally, there's the CF door, which releases with a sideways press on the latch. Inside is a big button that releases the card with ease. 

The bottom panel has slightly raised ribs traversing it, to provide better friction when mounted on a tripod head. Otherwise, it's very flat, making for nice, level mounting on tripods. The metal tripod mount is aligned with the optical axis of the lens. (This will somewhat simplify parallax control on shots to be stitched into panoramas, but note that you'll still need to offset the axis of rotation slightly forward, to position it under the optical center of whatever lens you're using.) The battery compartment is on the right side of the body. A thumbnail-activated lock releases the battery door, and the battery falls free.- Note that there is no sub-latch to keep the battery in place in case the door opens accidentally. Opposite the battery compartment on the left side (when viewed from the back) is a very small rubber Reset button to be used as a last resort, when the camera cannot be reset by other means.

Viewfinder

Like all SLRs, by definition the D70 has an optical viewfinder that receives light through the same lens that will direct light to the imager when the mirror flips up and the shutter opens. Rangefinder-style cameras have separate optics for viewfinder and imager, so the image can be slightly off due to what's called parallax error. This is largely eliminated with LCD viewfinders on consumer-grade digital cameras, but delay can be increased because the LCD usually lags behind reality at least a little bit. An SLR design allows the user to see the very view that the camera will see at the speed of light, eliminating some of the lag factor. An illuminated display inside the viewfinder provides detailed camera and exposure information, including focus area indicators, focus confirmation, focus mode, shutter speed, aperture, metering, AE/FV lock, battery status, exposure and flash compensation, frame counter, and flash ready light. When activated through the menu, the view also includes an alignment grid, useful for lining up difficult shots. That this can be turned on and off indicates that an LCD-equipped mirror is employed in the Pentamirror arrangement (we're seeing lower cost SLRs sporting Pentamirrors rather than Pentaprisms. This is also true in Canon's Digital Rebel. Pentamirror finders are supposed to be less bright than Pentaprisms, but I haven't found any huge disadvantage among the cameras I've reviewed. A Pentaprism is a solid piece of crystal or glass that is more expensive than a set of mirrors, and that also adds weight to the camera body.)

The LCD panel is not usable as a viewfinder on digital SLRs, for the simple reason that the mirror is directing light to the optical viewfinder, completely obscuring the digital sensor until the time of exposure. It can, however, provide a good deal of information after an image has been captured, demonstrated mightily in the D100 and D70 designs. No fewer than seven different display screens are available, ranging from no information other than the 130,000 pixel picture, to very detailed lists of the settings, plus a histogram, and an overexposure alert. The histogram is a graph of how many pixels in the image have each brightness level. The brightness is the horizontal axis, running from black on the left to white on the right. The height of the graph shows the number of pixels at that brightness level. This kind of display can be very helpful in determining over- or underexposure. An evenly-exposed, low-contrast subject would create a histogram that stretches across the entire width of the display, using the full range of brightness values available. An underexposed image will have a histogram with all the data lumped on the left of the histogram, and an overexposed image would be bunched up on the right.

Another display mode that's useful is the Highlights display, which flashes any overexposed areas, alternating white and black. Few objects should appear as pure white in a well-exposed photograph, because few objects in the real world are pure, saturated white to our eyes. Obvious exceptions are light sources, like lamps and the Sun. The flashing Highlights display is thus very useful for seeing any parts of the image that might be overexposed. It's particularly helpful when only isolated highlight areas are overexposed. Because the histogram display shows the distribution of all the pixels in the image, small overexposed areas don't produce a noticeable blip on the graph, making them easy to miss. The Highlights display takes care of that, by calling attention to overexposed regions very directly.

Though it's buried in the control buttons, the D70 has the ability to zoom in on photos up to 4x to examine focus in playback mode. The animated series of shots shows how this works. As you enter a zoomed playback mode, the display changes from a 3:2 ratio view, which shows the entire image, to a 4:3 ratio, matching the dimensions of the LCD. Once you've entered zoomed playback mode, pressing the Thumbnail display button (of all things) while rotating the Main control dial zooms in on the image. Once zoomed, you can use the Four-way rocker to move around inside the image. Pressing the Thumbnail display button toggles to a display showing the position for your zoomed window within the normal-sized image, indicated by a bold red outline. You can move this window around with the Rocker Pad control, and then pop back into the zoomed view by releasing the Thumbnail button again. This may all sound a little complicated, and it is, but after very little acclimation, I found I could move around within the enlarged display very fluidly using this arrangement. See the animated screen shot above for a whirlwind tour of the feature. Pressing Playback Zoom/Quality/Enter button zooms you in and out by 2x, and you can move around with the navigator button.

Optics

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The D70 accommodates a wide array of Nikkor lenses via the standard Nikon F lens mount. It will work with older AF lenses that are driven by a mechanical coupling or with the newer AF-IF or AF-S Nikkor lenses with internal focusing motors. Despite this backward compatibility, Nikon recommends the D70 be used with type G or D lenses. These models inclued a microchip to communicate distance information to the camera, and the G models have apertures that work via electrical contacts, and so have no aperture ring on them (On older lens models, the aperture ring must be locked at its minimum setting to be used in automatic modes.) IX-Nikkor lenses, originally built for APS cameras, are expressly unable to work with the D70.

Functions and exposure modes available with a given lens will vary greatly depending on type. G and D type lenses include a microchip that communicates focal distance information to the camera. Lenses without the microchip will disable 3D-Matrix metering mode. See the table below for a brief idea of the functionality available with different Nikkor lens types (abstracted from the D70's manual, used by courtesy of Nikon USA, Inc.)

The D70 comes in two packages, either bundled with a lens specially designed for the camera, or body only. As such we'll discuss working with the bundle's 18-70 f/3.5-8.5 ED glass DX lens. As was said of the Canon Digital Rebel's 18-55mm lens, getting the camera without the lens would be a mistake, since it will only be available at a higher price than the bundle after the fact. Body only, the camera is $999 street, with the lens it's $1,299 street. Separately, the lens will likely street at $400 with an SRP of $590. Though many prospective buyers will have a few Nikkor lenses, most consumers will not have an 18mm lens, something necessary to achieve true wide-angle shooting with the "DX" sized sensor used in the D70 and other Nikon d-SLRs. (An 18mm lens on the D70 produces the same field of view as a 27mm lens on a 35mm camera.)

This is an excellent ED glass lens, equivalent to a 27 - 105mm lens on a 35mm camera, with all the necessary electronics to make it 3D matrix metering capable, and a Silent Wave focusing motor. Frankly, as a bundle or otherwise, it's a bargain. Its closest equivalent among Nikkor lenses is the AF-S 17-55mm F2.8G ED DX currently going for $1,400. That's more than the D70 and its lens combined, so unless you already own one of these, strongly consider the bundle. Admittedly a zoom that starts at F2.8 is worth a lot of money, but the 18-70mm's range of f/3.5-4.5 is only a half a stop to a bit more than one stop slower, so consumers will do just fine with it.

The 18-70mm has an F3.5 - 4.5 range, something the Digital Rebel's short back focus EF-S lens does not equal despite its shorter zoom ratio, coming in at F3.5 - 5.6. A look at both side by side tells the story, with the Nikkor offering a far larger objective lens, usually indicating greater light gathering ability. Another subtle advantage of the Nikon 18-70: It uses internal focusing, so the front element doesn't rotate when the camera focuses. This means that the angle of a polarizing or other special effects filter attached to the filter threads won't change as the lens is focused. Also, thanks to its use of the Silent Wave focusing motor, you can manually focus the lens at any time, without having to disengage the camera's focusing mechanism. All this is not to discount the achievement in quality, light weight, and low cost of the Canon EF-S lens, a surprisingly good lens for the money, but I mention it to underscore that for only $300 more than the Rebel's bundle, you're getting a lot more lens. (As well as a good bit more camera, as we'll see later.)

Nikon's ED glass helps minimize chromatic aberration, ED being the company's designation for their high-end line, which uses Extra-low Dispersion glass. The lens has an information window that shows the current focus setting in feet and meters, with raised gold lettering all around. Its mechanisms are all very smooth, with no slop or play, giving a feeling of precision. The hard rubber grips on the focus and zoom rings are textured such that they're easy to hold as well as tell apart by touch. The lens body is metal, with a spatter-painted black texture that matches the texture of the D70's body. The front of the lens is internally threaded for a filter, and has external flanges for the included HB-32 lens hood. The overall impression given by the lens' appearance alone is one of precision and excellence. Using the lens tells the same story.

Focus options

The D70 lets you take advantage of auto or manual focus via a small switch on the front of the camera, next to the lens. Setting the switch to "M" puts the camera into manual focus mode, and AF puts it into Auto Focus mode. As just noted above though, AF-S lenses with the built-in Silent Wave focus motor let you manually focus the lens at any time, regardless of the cameras focus setting. To select between the two types of AF, you need to go to the camera menu and Custom Setting 2 and choose between AF-S (Single Servo) and AF-C (Continuous Servo). Single Servo simply means that the camera sets focus only once, when the Shutter button is first pressed halfway, and is best for still objects. Continuous Servo means that the camera continuously adjusts the focus, as long as the Shutter button is halfway pressed, and is best for moving objects.

There's an important difference between Single and Continuous Servo modes: In Single Servo mode, the shutter won't release unless the lens has achieved focus (Focus Priority). In Continuous Servo mode however, the camera will fire regardless of the state of focus (Release Priority). If you want to be sure that the camera is focused when you snap the picture, use Single Servo mode. Use Continuous Servo for moving subjects, and/or times when the specific instant of shutter release is more important to you than guaranteed sharp focus.

As discussed earlier, focus can be confined to one of the five specific focus points in Single Area mode, or with Dynamic Area which offers focus tracking. Single Area AF simply means that the camera sets focus based on the specific area you've designated. Dynamic AF employs all five of the autofocus areas. When Dynamic Area focusing is enabled, the camera first focuses on the subject in the chosen focus area. When the subject moves to a different AF area, the camera shifts the focus to "follow" the subject. This is great for irregularly moving subjects. (Sports and kids come to mind.) Closest Subject Priority was automatically enabled in both Dynamic and Single Area on the D100, but now it occupies its own slot in the control system. This option means that the camera first focuses on the closest object that falls into one of the five focus points.

In Single Area AF mode, you can change the primary focus area by unlocking the Multi selector (the Four-Way Arrow pad on the back panel) with the sliding switch beneath it and then shifting the focus area using the up, down, right, or left arrow keys. You can lock the focus area selection by turning the switch back to the lock position. By default, the D70 does not "wrap" the focus area selector as you scroll between focus areas. Through the Custom Settings menu though, you can opt for a "Wrap" function. What this means is that if you press the right arrow key again, after the right focus area is already selected, the selection will immediately jump to the left focus area. The same happens when moving the focus area selection vertically.

There are two methods by which you can lock focus on the D70. The first is via the shutter button, placing your subject in the selected focus area, halfway pressing and holding the Shutter button, then realigning the composition and firing the shutter. (This is the default behavior of the shutter button, but it can be disabled.) Unlike most cameras, you can choose whether or not the shutter button also locks exposure, via an option on the Custom Settings menu.) Alternatively, when using Single Servo AF, you can press the AF-L/AE-L button to lock focus (and exposure, unless the button is set for focus-only in the Custom Settings menu). Keeping this button pressed will maintain the focus and/or exposure lock, even if the Shutter button is released. This lets you recompose the photograph without keeping your finger on the Shutter button, but on the AE-L/AF-L button instead. (Reducing the chance that you'll accidentally trip the shutter when you don't intend to.)

There are several options available for the AE-L/AF-L button, which can be set via Custom Settings Menu 15. You can program it to lock either focus or exposure separately, or both together (the default). You can also change its operation so a single press locks and holds the exposure setting. (No need to keep the button pressed down.) Finally, you can set the AE/AF lock button so it alone controls the autofocus system, meaning the autofocus won't actuate when the shutter button is half-pressed, only when the AE/AF lock button is pressed instead. Finally there's the FV lock option, which locks the flash level and keeps it locked until the button is pressed again. (If you're a novice user considering purchasing a D70, and all this sounds confusing, don't let it worry you: The camera's default operation is very straightforward, but the availability of features like these is really liberating for more advanced users.)

Everyone understands that lenses sometimes get dust on them and need to be cleaned, and there are a lot of lens-cleaning cloths, solutions and other accessories on the market that work well. BUT, what do you do when your sensor gets dusty? Dust specks on the sensor tend to show up when shooting at very small apertures, appearing as dark blobs on your images. They're distracting at best, a terrible nuisance at worst, if you end up having to retouch every image to rid of them.

Most of us are naturally leery about the idea of poking around inside the delicate innards of our d-SLRs to wrestle with recalcitrant dust specks. Gently blowing the sensor surface (actually, the surface of the anti-aliasing filter) with compressed air gets rid of some dust, but there's invariably a lot that just stays stuck, no matter what. So what do you do?

If you've got dust specks on your sensor (and sooner or later you will), you're going to need to clean it. There are a lot of products out there intended to address this need, but a distressing number of them work poorly (if at all), and many are grossly overpriced. Advertising hype is rampant, with bogus pseudo-scientific jargon and absurd product claims run rampant. And prices - Did I mention prices? How about $100 for a simple synthetic-bristle brush?

So how do you know what product to use?

We don't pretend to have used everything currently on the market, but can tell you about one solution that worked very well for us. The "Copper Hill" cleaning method is straightforward and safe, and in our routine usage here at Imaging Resource, highly effective. Better yet, the products sold by Copper Hill Imaging are very reasonably priced. Best of all, Nicholas R (proprietor of Copper Hill) has put together an amazingly detailed tutorial on sensor cleaning, free for all.

Sensor cleaning is one of the last things people think about when buying a d-SLR, but it's vital to capturing the best possible images. Take our advice and order a cleaning kit from Copper Hill right along with your d-SLR, so you'll have it close at hand when you need it: You'll be glad you did!

(Other than a few backlinks on their site, we receive no promotional consideration from Copper Hill. We just think their sensor cleaning products are among the best on the market, and like their way of doing business. - We think you will too. Check them out.)

Exposure

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Available exposure modes include Program AE, Manual, Aperture Priority, and Shutter Priority modes. Also new are full Auto and Digital Vari-Program modes (similar to the Scene modes on Nikon's consumer digicams), including Portrait, Landscape, Close up, Sports, Night landscape, and Night portrait. Shutter speeds from 30 seconds to 1/8000 second are available, plus bulb for exposures up to 30 minutes. In Program mode, you can use the Main command dial to adjust the camera's selection in favor of a higher shutter speed and a larger aperture, or vise versa if the options are available, handy for when you want to emphasize shutter speed or aperture.

ISO sensitivity ranges from 200 to 1600, adjustable by pressing the ISO button and turning the Main command dial to change the setting on the Status LCD. It can also be changed in the menu. A Noise Reduction mode in the settings menu reduces fixed-pattern image noise when shooting at the higher sensitivity settings at longer exposure times. White balance modes include Auto, which covers almost the entire range from 3,500K to 8,000K. It can also be set manually for Incandescent (3,000K), Fluorescent (4,200K), Sunlight (5,200K), Flash (5,400K), Cloudy (6,000K), Shade (8,000K), or Preset, which the user sets based on a white or gray object in the scene or a pre-captured photograph. I found the auto white balance generally did a good job, and the Preset option was very accurate under a wide range of lighting conditions. My biggest gripe is that neither Auto nor Incandescent reach down far enough to handle the household incandescent lighting that's so common in the US. (Although Incandescent can be tweaked enough to almost get there.) Why can't digicam companies make auto white balance options with enough range to cover this very common light source?

White balance can be fine tuned by pressing the WB button and turning the sub-command dial. It can be adjusted from -3 to +3 in increments of 1, but the actual step size varies as a function of the white balance mode that's selected. See table below for details, which shows the lighting color temperature that each setting corresponds to. 

The D70 has three metering options, 3D Matrix, Center Weighted, and Spot. The 3D Matrix setting integrates exposure information from 1,005 areas across the entire screen, as opposed to most multisegment sensors that have from 10 to 35 areas to analyze. The scene viewed by the metering sensor is compared to a database of common photographic situations to help the camera decide whether the image consists of a backlit subject, for example, or else a dark foreground object. This information is enhanced (essentially made "3D") by the focus distance information shared from the microchip in the D- and G-series lenses. All Nikon SLRs use some form of matrix metering, but the D70 is the first time that the full 1,005-element RGB sensor originally introduced in the flagship F5 film-based model has been deployed in an "entry level" d-SLR. It's by far the most sophisticated metering system of any d-SLR currently on the market for less than $3,000. The net result of all this is a more frequently accurate metering response than that produced by center weighted metering, especially if the subject is off-center. In practice, I found the D70's metering to generally be quite accurate. It seemed to have a tendency to slightly underexpose most shots by 0.3 to 0.7 EV, but it was pretty consistent in this, leading me to believe that this might represent a deliberate choice by its designers, to avoid losing highlight detail. Overall, I felt pretty confident of getting the exposure I expected with the D70, after relatively little time spent with the camera.

As to the other metering options for the D70, center-weighted metering takes a light reading from the entire image area, but places the greatest emphasis on a circular area in the center. In an unusual feature for an "entry level" d-SLR, as Custom Function menu option lets you select how large an area contributes toward the center-weighting. Options are 6, 8, 10, and 12 mm, with 8mm being the default. Spot metering in the D70 takes a reading from the center one percent of the image area, excellent for quick measurements from a face without having to close the distance much.

The D70's Exposure compensation adjustment lightens or darkens the overall exposure anywhere from -5 to +5 EV units, in one-third step increments. It can also be adjusted to work in half step increments. Note though, that exposure compensation does not work in any of the Digital Vari-Program modes. As noted above, I found the D70 to fairly consistently underexpose shots by about 0.3 EV, since most of my shots were better when set from +0.3 to +0.7 EV. By default, test shots captured under harsh lighting showed the D70 to be quite a bit more contrasty than I'd personally prefer, although the color from the D70 is excellent. There is a variable contrast control buried in the shooting menu that lets you adjust the contrast level to low, normal, or high. I found that this worked fairly well, but a little differently than some. Rather than leaving the midtones at the same brightness and pulling in or pushing out the shadow and highlight values, the contrast adjustment on the D70 leaves the highlight values undisturbed, and adjusts the midtone and shadow levels to affect the contrast. This is good in that it means the camera will hold onto essentially the same highlight detail, regardless of how you have the contrast set, but it also means that contrast adjustments have a pronounced effect on overall image brightness. At the end of the day, the results are the same as a more conventional approach, but it might take a little different approach to understanding exposure and contrast adjustment than many amateurs are accustomed to. (The D70's behavior in this regard will actually be well-suited to pro shooters, who are accustomed to metering for the highlights first and foremost. Here, the approach that's implemented is to expose for the highlights, then use the contrast adjustment to control how you want the midtones and shadows to appear.)

An auto-bracketing feature takes three shots of the same subject with varying exposure values determined by either the photographer in manual mode or by the camera in all other modes. The exposure steps for bracketing can vary across a range of -2 to +2 EV (values are added to the already chosen exposure compensation value), in increments of either one-third or one-half. Through the Custom Settings menu, the Bracketing function can also be set to adjust white balance or flash exposures only. (By default, both ambient and flash exposures are bracketed.)

The D100 also offers Sharpness, Tone Compensation (Contrast), and Hue adjustments, accessed through the Shooting menu. I mentioned the contrast adjustment feature above, but its Custom option deserves special mention. What's unusual here (for an entry-level d-SLR at least) is that the Custom tone compensation option accepts downloaded tone curves from a computer. (If no curve is downloaded, the Custom setting defaults to the Normal setting.) This lets you completely define the camera's tonal characteristics via the computer, something that has heretofore only been available on the highest-end d-SLR models.

For those familiar with the concept of the "color wheel", which arranges visible colors in a circle, Nikon's Hue adjustment will make sense: It offers a range of adjustment from -9 to +9 degrees around the color wheel. (A complete circuit of the wheel being 360 degrees.) If you don't carry a degree-calibrated color wheel in your head, I've provided the illustration of a color wheel at right. The dark bars show the total shift that the full 18 degree range of adjustment offered by the D70's hue control can produce. - As you can see, it's a fairly subtle adjustment. Note too, that the effect on any given color will depend on where that color is around the wheel. For red colors, a positive adjustment will shift the red toward orange, while a negative adjustment will shift it toward purple. For blues though, positive adjustments shift the color toward purple, while negative adjustments shift it toward cyan. The rollover image below shows the effect of going from -9 to +9 on the Hue adjustment - The -9 shot is visible by default, move your cursor over the image to see the effect of the shift to +9 degrees.

When reviewing images on the LCD monitor, you can call up a histogram and a highlight function to give you a complete readout on the exposure. This is a useful tool to examine your exposure in the camera instead of waiting to download images and then deciding to reshoot. As I noted in my discussion of these features in the Viewfinder section of this review, I'd like to see the Highlight function be a little more restrained in its reporting of overly-strong highlights. (Actually, the ideal would be to let the user select at what brightness level the highlight warning should activate. Why hasn't any manufacturer done this yet?)

Continuous Shooting Mode
Nikon claims that the D70's Continuous Shooting mode captures 3 frames per second, depending on the amount of image information and available Compact Flash space. In practice, I clocked it at 2.92 fps, quite close. When using a fast Compact Flash card, like a SanDisk Extreme or Ultra II or presumably one of the even faster Lexar 80x cards that are coming (May, 2004), the buffer doesn't fill very quickly. One can watch the counter move down to about a five-frame capacity and slowly move down then back up again. The faster the card, the more quickly the buffer can offload the data, and in the case of high resolution with "normal" or "basic" compression, the buffer may never fill at all. This is truly amazing, and a first with any digital camera I've seen. Do note though, that this effect requires a card of 60x or more. (Finally, a camera that really takes advantage of fast memory cards!)

Image Noise
Overall, the D70 has very good noise characteristics. The chart below shows a plot of noise magnitude vs ISO value for the D70 and Canon Digital Rebel, but as usual, the chart tells only a small portion of the story. While the D70 shows numerically higher noise levels, particularly at very high ISO settings, in actual fact, the noise pattern of the D70 is a good bit finer-grained. This makes it noticeably less objectionable to the eye. Bottom line, I found the D70's images shot at ISO 1600 to be thoroughly acceptable for all but the most critical applications. For routine shooting of family memories, I have no qualms about running the D70 at its maximum ISO setting on a routine basis.

What's up with RAW?

Like many high-end digicams, the Nikon D70 has a "RAW" file format as an option. If you're new to the world of high-end digital cameras, you may not be familiar with the concept of the "RAW" file format. Basically, a RAW file just captures the "raw" image data, exactly as it comes from the camera's CCD or CMOS image sensor. So why would you care about that? - RAW files let you manipulate your images post-exposure without nearly as much loss of image quality as you'd get with JPEG files. A full discussion of RAW file formats is way beyond the scope of this article, but Charlotte Lowrie of MSN Photo has written an excellent article describing the benefits of the RAW format, titled A Second Chance to Get It Right. Check it out, it's one of the clearest tutorials on RAW formats I've seen yet.

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.