Nikon D3S Live View

Nikon D3S Live View

"Live View" has become a fairly common feature on DSLRs, both at the consumer and professional level. For pros, it's probably less driven by the convenience of framing on an LCD than it is by the need for a viewfinder display when the camera is operated remotely. (Although Live View features that provide for highly magnified displays can be a considerable help in checking depth of field and focus accuracy.)

Nikon debuted its Live View feature in its D3 and D300 models, both announced in August 2007, and the D3S retains the bulk of the D3's Live View functionality unchanged. As well as integrating the Virtual Horizon overlay which was added to the D3 after release via a firmware update, the D3S does have a few notable differences from the D3's live view mode, however. Most significantly, Live View is no longer restricted to its own position on the Release Mode dial. Instead, the D3S offers a dedicated Live View button on its rear panel, adjacent to the Microphone button at the right end of the rear control panel LCD. That also means all drive modes are available in Live View mode. (On the D3, release modes in Live View mode were menu driven, and limited to Single, Continuous Lo and Continuous Hi). We did however notice the frame rate in Continuous Hi mode seemed a lot slower than with the optical viewfinder. Finally, the D3S' new Movie mode (described on the Video page of this review) is accessed through the Live View function, by pressing either the Depth-of-Field Preview button or the center button of the multi-selector.

As in the company's past DSLR models, Nikon's Live View mode provides two options for autofocus operation, dubbed Hand-Held mode and Tripod mode. With the mirror raised and shutter open, the light path to the usual SLR phase-detect AF sensor is interrupted, so normal AF can't be used. The Hand-Held mode addresses this problem by dropping the mirror to determine focus, and then opens it again to restore the Live View display. In this mode, either the shutter release or AF-ON button can be used to autofocus. Fully depressing the shutter release will focus and capture the image, just as it does when using the optical viewfinder.

On the plus side, the focusing operation itself is just as swift and reliable as in non-Live View shooting. The main disadvantage of this mode is that there is an interruption to the Live View feed, equivalent to the time taken to lower the mirror, perform the focusing operation and raise the mirror again. It's also possible that an unfamiliar photographer could be fooled into thinking that the mirror noise means that a photo has been captured, when in fact the camera has only focused -- something Nikon is careful to note in its manual. Also, the focus area on the LCD monitor does not change to green to indicate focus has been achieved, or blink red when it has not, like it does in Tripod mode (see below). So, unless you have focus beep on, or prefocus and check with magnification (see below), there is no positive indication of focus in Hand-Held mode before you take the shot. In situations where one has to keep intrusive noise to a minimum, the mirror cycle accompanying every AF operation might also be seen as a disadvantage, however the D3S's Quiet Shutter release mode is available. (See the Exposure page for details.)

You can magnify the image around the selected focus point by up to 13x, and the camera remembers the magnification after the image is captured, so you can quickly check if autofocus produced the results you intended.

Exposure is always just "estimated" in the preview for Hand-Held mode. Shutter speed, aperture and ISO displayed do no update real-time in response to changes in lighting after Live View mode was enabled, and there is no exposure meter like there is in the optical viewfinder. The effects of White Balance and Picture Control settings are shown on screen, but that's about the extent of simulation. For instance, you can dial-in negative exposure compensation, or select a very fast shutter speed in low light in Manual exposure mode, and the resulting preview image would look fine while the captured image would be underexposed. Automatic exposure settings do update during the autofocus operation however, since the metering sensor is also active during autofocus in this mode, so images captured in Hand-Held mode should have identical exposure compared to using the optical viewfinder under the same conditions. For a more accurate, real-time representation of the final image and automatic exposure settings, you'll need to use Tripod Mode and enable Exposure Preview (see below). Although all three metering modes are supported in both Live View modes (except when Exposure Preview is enabled), you cannot just change the metering mode and have the display immediately reflect that change. In Hand-Held mode, you either have to leave and re-enter Live View mode to change metering modes, or wait until after an autofocus operation or a frame has been captured, as that's when the metering sensor is exposed.

Nikon's second Live View autofocus option is Tripod mode. In this mode, the camera performs contrast-detect autofocus, just like any point & shoot digicam. That is, it simply reads data off the CMOS image sensor and evaluates how abruptly light to dark (or dark to light) transitions happen on the image plane. Autofocus is performed only by pressing the AF-ON button in this mode; half-pressing the shutter release does nothing, and full depressing it will not attempt to refocus before capture. Contrast-detect AF isn't nearly as fast as phase-detect (this is why the shutter response of most digicams is so much slower than that of most DSLRs), but the camera can focus without interrupting the Live View display (and without all the mirror flipping noise). As an added benefit, because it's working with data coming from the main image sensor, you can move the AF point anywhere you want within the frame area, right out to the extreme edges. You're also guaranteed that the selected focus area will be in focus if the camera is able to find focus: Because the focus determination is made with data from the main image sensor, there's no possibility of front- or back-focus, as could be encountered with conventional phase-detect AF systems.

Of course there's no such thing as a free lunch, and Tripod mode's potential disadvantage is made clear by Nikon's choice of name. The company has consistently emphasized that this mode is only for use with stationary subjects, and with the camera mounted on a tripod. Depending on the circumstances, Live View Tripod mode can stretch shutter lag to as long as several seconds, depending on the lens in use and how far the starting point is from the final focus distance. With a moving subject (or a handheld camera), it's quite likely that the contrast detection AF simply wouldn't be able to keep up with the motion, and would be left hunting, unable to achieve a focus lock.

Like Hand-Held mode, the D3S also offers the very useful 13x display zoom in Tripod mode, providing excellent focus discrimination when focusing manually. This is pretty key: Less than about 10x magnification really doesn't do the trick for getting the focus set right, but in playing with the camera at 13x, we felt we could pretty well nail the focus every time. What's particularly neat is that you can continue doing Contrast-Detect AF when the image is magnified, providing immediate feedback of exact focus. Also like Hand-Held mode, you cannot change metering modes while in Live View mode. Which ever mode was selected before entering Live View mode will be used, except when Exposure Preview is enabled, which always uses Matrix metering. (Though it meters data streaming from the image sensor, as the dedicated metering sensor is not exposed during previews.)

Very useful for studio shooting is the ability to preview exposure by pressing the "OK" button during Tripod mode. (As mentioned previously, Exposure Preview is not available in Hand-held mode.)  This is more accurate that the exposure "simulation" provided in Hand-Held mode, allowing exposure to be checked and fine-tuned before the final image is ready to be captured. Shutter speed, aperture and ISO (if Auto ISO is enabled) values are adjusted in real-time in response to changing lighting, just like they do when using the optical viewfinder. The lens aperture is actually stopped down to the selected value in this mode, which also provides depth-of-field preview. (The DOF Preview button starts and stops movie recording in Live View mode.)  There are a few limitations to this function, however. Only +/-3.0EV of exposure compensation can be previewed, although the camera will allow up to a +/-5.0EV range to be set -- greater values aren't reflected in the preview display. It's also obviously not possible to preview a bulb exposure, given that the camera won't know the exposure time until the photograph is actually captured. The effects of Vignette Control is also not previewed. Interestingly, where the Nikon D3 also didn't allow Exposure Preview with a flash strobe attached, Active D-Lighting or bracketing in effect, or the shutter speed at the X-sync value of 1/250 second, the D3S will allow preview in these circumstances - just with a proviso that the exposure may not accurately reflect that of the final image. As mentioned above, only Matrix metering is supported during Exposure Preview. If the metering mode switch was set to Center-Weighted or Spot before entering Live View mode, the metering icon in the Live View display changes to Matrix as soon as Exposure Preview is enabled.

With Live View mode comes the ability to control most, if not all aspects of the camera's functioning from a PC remotely, including focusing. Both the recent Nikons and Canons include the ability to control the camera from a computer remotely, and that includes receiving a Live View image from the camera. You can focus, adjust settings, and fire, all from a computer. What's more, you can do it via USB cable or Wi-Fi connection, with the optional Wi-Fi adapters. The Nikons require optional Camera Control Pro software to enable this feature. Software for this feature is bundled with Canon cameras. Of course, no software is needed to view the Live View display on a TV or monitor via the A/V or HDMI outputs.

All-in-all, the Nikon D3S's Live View mode is more capable than that of Nikon prosumer and consumer models such as the D300S and D90, and is easier to access with the dedicated Lv button than the D3 or D3X, but still isn't as seamless or as user-friendly as some competitors' implementations.