Nikon D4S Technical Info

by Mike Tomkins

Sensor

The Nikon D4S is based around a newly-developed, full-frame (or FX-format, in Nikon parlance) CMOS image sensor. Effective resolution is unchanged from that used in the earlier Nikon D4, at 16.2 megapixels. Total resolution of the sensor, which has dimensions of 36.0 x 23.9 millimeters, is 16.6 megapixels. Unlike many current DSLRs, the D4S' sensor still sits beneath an optical low-pass filter that subtly blurs incoming light, helping to reduce the frequency of moiré and false color artifacts.

In the sensor's native 3:2 aspect ratio, the Nikon D4S outputs images at resolutions up to 4,928 x 3,280 pixels. There are also two cropped 3:2 aspect ratio modes which yield an effective 1.2x or 1.5x focal length crop, and a 5:4 aspect ratio mode which uses the full height of the image sensor, but trims the sides.

Processor

In place of the EXPEED 3 image processor used in the D4, the Nikon D4S is based around a next-generation EXPEED 4 processor. The company says that the newer chip has 30% greater performance, and allows for better noise-reduction processing thanks to updated algorithms.

Sensitivity

A significant difference from the earlier camera can be found in the sensitivity range of the Nikon D4S, backing up the claims of improved noise processing. The new camera now offers a standard ISO sensitivity range of 100 to 25,600 equivalents, a full stop above the D4's range, which was curtailed at ISO 12,800 equivalent.

It's still possible to extend the ISO sensitivity range at both ends, with the D4S now able to encompass everything from ISO 50-409,600 equivalents. At the lower end of the range, that's unchanged from the D4, but the upper limit is again a full stop above the earlier model's ISO 204,800 limit.

The D4S also offers an Auto ISO function which takes into account the mounted lens type, automatically selecting higher shutter speeds when the attached lens has a longer focal length. It's possible to manually skew the Auto ISO function towards faster or slower shutter speeds.

Performance

Nikon has also improved burst shooting performance of the D4S compared to that of its predecessor. The increase -- from 10 frames per second in the earlier camera to 11fps in the new model -- is modest, but certainly worthwhile for sports shooters. (Note that you're now getting autofocus and autoexposure adjustments between shots at this rate -- the D4 could manage 11fps, but only if you locked both variables from the first frame.)

The burst depth has also gotten a subtle improvement. Previously the D4 was rated as good for 170 frames when using JPEG Fine compression. Now, the Nikon D4S is said to be good for 200 JPEG Fine frames. In raw mode, the D4S is now capable of 133 frames with lossless compression and a 12-bit depth, up from 92 frames for the D4. The improvement at 14-bit depth is more modest, up three frames to a total of 78 frames. The worst case is 60 uncompressed (down from 69), 14-bit raws, and the best case is 176 lossy 12-bit raws (up from 98).

Of course all these figures are manufacturer ratings, and at FX-format resolution; for DX-format shooting, you can expect 200 frames with all but 14-bit uncompressed and small 12-bit uncompressed raws. We only tested the depth with lossless raw+large/fine JPEG, where we managed an excellent 43 frames with our difficult-to-compress target.

Optics

Just like its predecessor, the Nikon D4S features a Nikon F-mount with autofocus coupling and contacts. As you'd expect, it's compatible with almost every F-mount lens made since 1977, although some lens types will have a few limitations.

Displays

On the rear panel of the Nikon D4S is a 3.2-inch diagonal LCD panel. It's the same size used on the D4, and resolution is unchanged too, at 921,600 dots. (That equates to 307,200 pixels in a 640 x 480-pixel VGA array.) Also unchanged is the wide 170-degree viewing angle both horizontally and vertically, and the 100% frame coverage.

The D4S's LCD now includes a function allowing the user to adjust color tone, though, a handy addition to the feature set of the earlier camera. You can also adjust brightness in five steps.

Of course, the D4S also has both top-panel and rear-panel monochrome status displays, just as found in its predecessors.

Viewfinder

The Nikon D4S also retains its predecessor's eye-level pentaprism viewfinder, but while the viewfinder itself is unchanged, a difference in the reflex mirror mechanism should make using it rather more pleasant. The new mirror mechanism reduced viewfinder blackout time, meaning that the viewfinder view is interrupted for a shorter period during exposures. That should make tracking moving subjects easier.

Viewfinder coverage is still 100% when used in uncropped FX 3:2 aspect ratio mode, and 97% when in the 1.2x or DX cropped modes. For the cropped FX 5:4 aspect ratio mode, coverage is 100% vertically, but only 97% horizontally. When shooting in modes other than the native FX-format 3:2 aspect ratio, a translucent LCD in the viewfinder of Nikon's D4S partially masks the inactive portions of the frame.

The viewfinder has 0.7x magnification at 50mm and -1 diopter, an 18mm eyepoint, and a diopter adjustment range of -3 to +1m^-1, all unchanged from the last several generations of Nikon pro flagships.

Focusing

The D4S is still based around Nikon's 51-point autofocus module, the Advanced Multi-CAM 3500FX, but that doesn't mean there's been no change -- far from it. The company says that its autofocus algorithms have been "thoroughly recalibrated" for better performance, and the AF Lock-on function should now deal with focus interruptions more quickly, restoring focus to your intended subject.

The Nikon D4S also sports a new Group Area AF mode, in which you pick an autofocus point, and the four surrounding points are also activated. It's similar to Canon's AF Point Expansion function, and should help to keep focus locked when panning to follow moving subjects. Essentially, your chosen center point is favored for focus determination, but if the focus distance for that point suddenly changes while remaining little changed at an adjacent point, the D4S will assume you've accidentally slipped off your subject, and switch points automatically.

The Multi-CAM 3500FS sensor has a working range of -2 to +19 EV (ISO 100, 20°C/68°F). Of the 51 points arrayed across the sensor, 15 points located at the center are cross-type, sensitive to both horizontal and vertical detail, and nine of these work at apertures up to f/8 with compatible Nikkor lenses mounted on the TC14E or TC17E teleconverters, while the centermost point works at up to f/8 with compatible Nikkor lenses and the TC20E teleconverter. (The remainder work as cross-type sensors to f/5.6 or lower.)

As well as using the full 51 points of the AF array, it's also possible to select single-point, 9-point, or 21-point modes.

Shutter / Mirror

The Nikon D4S offers shutter speeds ranging from 1/8,000 to 30 seconds in steps of 1/3, 1/2, or 1 EV, as well as a bulb position, all unchanged from the D4. Flash x-sync is still at 1/250 second. The shutter unit still has a rated life of 400,000 cycles, and interestingly, we've learned that this rating was determined by testing the camera in-situ in a camera body, rather than on a workbench.

As noted previously, the D4S has a new mirror mechanism that reduces bounce and viewfinder blackout time. Nikon hasn't provided any figures for the scope of the improvement, but it makes tracking of moving subjects easier.

Exposure

Also retained is the Nikon D4's exposure metering system. The Nikon D4S determines exposures with a 91,000 pixel RGB metering sensor. Thanks to the high resolution and the presence of color information, the system can recognize and account for human faces when performing metering, even when shooting using the optical viewfinder.

Metering modes include 3D Color Matrix Metering III, Color Matrix Metering III, Color Matrix Metering, center-weighted (which either gives a 75% weight to an area of 8, 12, 15, or 20mm at the center of the frame or averages the entire frame), and spot (which meters on a 4mm / 1.5% circle centered on the selected focus point.) The precise matrix metering mode available depends upon the mounted lens type.

The Nikon D4S provides an exposure compensation range of -5 to +5 EV, set in increments of 1/3, 1/2, or 1 EV. Additionally, it's possible to bracket anywhere from two to nine frames, in steps of 1/3, 1/2, 2/3, or 1 EV, both for flash and available-light exposures.

White balance

Nikon says that its white balance calculations have been further refined in the D4S, ensuring greater accuracy. A spot white balance function is available, and as well as two Auto, six Custom positions, and Kelvin, there are a selection of twelve preset modes. White balance presets include incandescent, fluorescent (7 types), direct sunlight, flash, cloudy, and shade. White balance can also be bracketed with the D4S saving two to nine copies of each image with varied white balance.

Flash

The Nikon D4S includes both a standard flash hot shoe with sync and data contacts and a safety lock, and a sync terminal with locking thread. i-TTL flash exposures are metered using the 91,000 pixel metering sensor. As you'd expect, the D4S supports Nikon's Creative Lighting System. The SB-910, SB-900, SB-800, or SB-700 Speedlights can be used as a master flash, the SU-800 Wireless Speedlight Commander as commander, and the SB-600 or SB-R200 Speedlights function as remotes.

Creative

The Nikon D4S can still shoot time-lapse photography in interval mode, and has a time-lapse movie function which can assemble the results into a movie for you. However, the company says that it has improved the interval mode with an exposure smoothing function that more gradually changes exposure across frames, avoiding the flickery look that can result when your subject's brightness changes from the overall trend for a few exposures here or there.

As you'd expect, the Nikon D4S also includes the company's Active D-Lighting function, which tweaks the tone curve for more balanced exposures. The D4S's Active D-Lighting function includes one additional strength level beyond those in the D4, which is Extra High 2. Active D-Lighting can be bracketed, with anywhere from two to five frames saved with the ADL strength varying between frames.

The D4S also includes Nikon's Picture Controls function, which offers six presets -- Standard, Neutral, Vivid, Monochrome, Portrait, Landscape -- and the ability for the user to customize these and port settings between camera bodies.

Tilt sensor

As with its predecessors, the Nikon D4S includes a dual-axis level sensor, used to provide a Virtual Horizon function that helps ensure level horizons and parallel verticals. The rear-panel LCD can show a gauge similar to an aircraft attitude indicator, while the viewfinder and top-panel LCDs can be used to show side-to-side roll.

Video

Good news, video shooters. The Nikon D4S boasts further improvements to its video mode beyond those made in the previous D4. Thanks to the more powerful EXPEED 4 processor, it can now capture Full HD (1080p; 1,920 x 1,080 pixel) video at up to 60 frames per second (50fps for PAL), where its predecessor was limited to 1080p at 30 fps. Reduced frame rates of 30, 25, and 24p are still available, as well as a reduced resolutions of 720p (1,280 x 720 pixels) at either 60 or 50 fps, and 640 x 424 at 30 or 25 fps.

Videos are recorded using H.264 / MPEG-4 AVC format compression with linear PCM audio, and you can also still output an uncompressed, 8-bit, 4:2:2 Full HD live view feed via the D4S's HDMI port, allowing it to be recorded using an external device and/or routed to an external monitor. However, you can now opt to do both at the same time -- record H.264 video to the flash card, and output uncompressed HDMI, getting the best of both worlds.

Video can either be shot using data from pixels across the entire width of the image sensor in FX mode, or with either a 1.5x (DX-format) / 2.7x focal length crop, taking data from the center of the imager, without affecting the video resolution.

Video exposure

The Nikon D4S allows shutter speed, aperture, and ISO sensitivity to be changed during recording, as required to adapt to changes in ambient lighting or yield the desired cinematic effect. And like its predecessor, a Power Aperture function is included, allowing smooth and stepless aperture control using the Preview and Function buttons on the camera's front panel. However, unlike the earlier model, you can also opt to control shutter speed and aperture manually, but have the camera control ISO sensitivity so as to retain the metered exposure. (If subject brightness changes, the ISO sensitivity will gradually change so as to account for this.)

There's still full-time contrast detection autofocus capability, operating either in face detection, wide area, normal, or subject tracking modes, as well as the ability to focus manually.

Maximum clip length is 29 minutes 59 seconds at Normal quality and 20 minutes at High quality except for the new 1080p60/50 mode, which is limited to 20 minutes at Normal quality (24Mbps) and 10 minutes at High (42Mbps). Although there's a dedicated Movie record button, it's possible to configure the D4S to use the Shutter button to start and stop recording, allowing a greater range of accessories to control recording.

Audio

Audio levels for the built-in monaural microphone can be adjusted automatically or manually in a 30-step range, while external stereo mics have a 20-step adjustment range. The levels for either can be monitored on the camera's LCD display, and the levels adjusted during capture. There's a wind cut filter, as well, and this too can be enabled or disabled during capture. You can also now select between various frequency ranges for capture, such as Wide Range and Voice Range, so as not to pick up untoward noises outside of your intended capture range. Additionally, the Nikon D4S includes a standard 3.5mm stereo audio output, allowing headphones to be connected to the camera for live monitoring of captured audio.

One last video feature of note is the ability to select a frame rate and shooting interval for time-lapse photography, and then have the results saved as a video that plays back at speeds ranging from 24x to 36,000x. (And as already mentioned, exposure changes in time-lapse movies are now made more gradually.)

Environmental sealing

As you'd expect for a pro-level Nikon body, the Nikon D4S's tank-like magnesium alloy body is fully sealed and gasketed throughout, to protect against moisture, dust and dirt, and electromagnetic interference.

Dust reduction

Of course, as an interchangeable-lens camera, the lens mount itself is a potential entry-point for dust, and the D4S includes a dust removal function achieved using vibration of the optical low-pass filter. The Nikon D4S can also capture a reference image which determines the location of dust on the image sensor, and can be used to retouch photos to remove this dust, using Nikon's optional Capture NX 2 software.

Connectivity

Just like its predecessor, the Nikon D4S has an uncommonly wide range of external connectivity even by pro SLR standards. Connections include USB High-Speed data, a Type-C mini HDMI high definition video output, and an RJ-45 wired Ethernet port. However, where the Ethernet port of the D4 was 100Base-T compatible, that on the D4S is now a 1000Base-T port -- also known as Gigabit Ethernet, and capable of 185Mbps transfer. That's more than triple the rated speed of 60Mbps provided by the earlier camera.

The D4S also includes a ten-pin remote terminal (also used to attached compatible GPS devices), a 3.5mm stereo microphone jack (with support for plug-in power), and a 3.5mm stereo headphone jack (for monitoring audio during video capture).

Wireless file transmitter

The Nikon D4S is also compatible with the WT-5A wireless file transmitter. These allow images to be transferred directly from the camera to an FTP server or computer on the wireless network, and transfer can be initiated automatically or manually. The WT-5A draws its power from the camera body via a port beneath the strap lug on the left side of the camera body, and compared to the WT-4A -- with which the D4S is also compatible -- offers higher-speed 802.11n compatibility, linked release of up to ten cameras from a single camera body, and remote operation using Nikon Camera Control Pro 2 software.

GPS

As mentioned previously, the Nikon D4S can be connected to a GPS receiver, allowing geotagging of images as they're captured. As well as Nikon's own GP-1A hotshoe-mounted GPS receiver, the D4S is also compatible with NMEA0183 version 2.01 or 3.01-compliant GPS receivers, which can be connected to the camera using an optional MC-35 GPS adapter cord and the receiver's own connector cable with 9-pin D-sub connector.

Storage

The Nikon D4S has dual flash card slots, and can be configured to write images simultaneously to both cards, write raws to one card and JPEGs to the other, or use one card as primary and the second as an overflow when the first card is filled up. And like its immediate predecessor, only one of the slots accepts CompactFlash cards (Type-I only, including UDMA cards).

The other slot accepts the still-rare XQD-format memory cards, which were introduced by the CompactFlash Association in early December 2011. To date, they've still been adopted in the camera world solely by Nikon, and the D4S is only the second camera to offer support for them.

A nice, new touch is that you can now switch between cards as you're shooting with a two-button shortcut. Want to save just particular subjects or shot types to one card, and the remainder to the other? Now you can.

The D4S can write either 12-bit or 14-bit raw images with lossless or lossy compression, or completely uncompressed. It also has a new small, 12-bit raw file size, which saves with one quarter the pixel count (2,464 x 1,640 pixels) and half the file size of a standard 12-bit raw file. It can also save images as RGB TIFF files, Baseline-compliant JPEGs at 1:4, 1:8 or 1:16 compression levels, or as both raw and JPEG formats at the same time. A nice plus for wire service photographers is that the D4S can generate IPTC data in-camera, instead of at download time, streamlining the tagging process.

Power

The Nikon D4S draws power from a rechargeable EN-EL18A lithium-ion battery, rather than the EN-EL18 pack of its predecessor. The new battery is the same size as that used in the D4, but rated for significantly greater battery life in the new camera. CIPA testing suggests that the EN-EL18A battery will deliver up to 3,020 shots per charge in single mode, up from 2,600 shots with the EN-EL18 in the D4. And while doing so doesn't comply to CIPA standards, Nikon says that switching to continuous drive mode will allow 5,960 shots on a charge.

The D4S's battery is charged via the Quick Charger MH-26a, and an EH-6b AC Adapter can be used to power the D4S, requiring the EP-6 Power Supply Connector.