It's been two years since Nikon introduced their flagship SLR, the D4. While that camera has undoubtedly stood the test of time, Nikon has decided that it's time for a refresh. That camera is the D4s which, on the surface, doesn't look much different than its predecessor. That's because, by and large, the major changes to the D4s are inside its magnesium alloy body.

The biggest changes on the D4s are its processor (now covered by the Expeed 4 standard), wider ISO range (topping out at 409,600), group area AF feature, and slightly faster burst speeds. Nikon has also reduced viewfinder blackout time, made transitions more 'smooth' when shooting time-lapse, and added 1080/60p video recording. Movie aficionados will also enjoy the ability to use Auto ISO when using manual exposure, audio range and level adjustment, and the ability to output uncompressed video over HDMI while simultaneously recording to a memory card.

Nikon D4s key features

  • 'Newly designed' 16 megapixel full-frame CMOS sensor
  • Expeed 4 processing
  • ISO 100-25,600 (expandable to ISO 50 - 409,600 equiv)
  • 51-point autofocus system (same as D4)
  • Group Area AF allows for more accurate subject tracking with less 'distraction'
  • 11 fps continuous shooting with continuous AE/AF
  • New 'small' Raw size (approx. 8 megapixel)
  • 1080/60p video for up to 10 mins at 42Mbps or 20 mins at 24Mbps
  • Smoother transitions when shooting interval or time-lapse stills/movies
  • CompactFlash and XQD card slots
  • Gigabit Ethernet port, in addition to support for WT-5A wireless transmitter
  • EN-EL18a battery provides 3020 shots per charge (CIPA)

In addition to those features, there are numerous small changes that have been made, with the Expeed 4 processor having a lot to do with it. Probably the biggest benefit of Expeed 4 is a wider ISO range, which now tops out at a whopping 409,600 (this is the Hi4 setting). The processing system has also increased the top burst rate to 11 fps (with AF). And speaking of increased speed, the D4s' mirror has a shorter travel distance, which reduces viewfinder blackout times.

There have been subtle changes to the camera's exposure system, starting with the ability to use face detection to determine metering while using the OVF. Exposure changes when using live view, interval shooting, or time-lapse movie are now less abrupt. Speaking of interval shooting, you can now take up to 9999 shots per sequence. The Active D-Lighting feature now has an 'Extra High 2' setting, though Nikon says that will look pretty 'artsy' at that point.

Another small change worth mentioning is the camera's ability to use the Auto ISO feature while in manual exposure mode. This allows you to choose a shutter speed and an aperture setting and let the camera decide on the necessary ISO. And, because the D4s has an Exposure Comp button as well as two control dials, you can apply exposure compensation so that you get your chosen image brightness, when working this way.

The D4s uses the new EN-EL18a battery for power, which allows for an incredible 3020 shots per charge (CIPA standard). Those who own EN-EL18 batteries can use them as well.

Compared to D4

Below is a quick comparison of the major differences between the D4 and D4s:

 
Nikon D4
Nikon D4s
Sensor
16.2MP FX-format CMOS
Processing Expeed 3 Expeed 4
ISO range (standard) 100 - 12,800 100 - 25,600
ISO range (expanded) 50 - 204,800 50 - 409,600
Group AF area No Yes
Maintains focus point when changing orientation No Yes
Continuous shooting w/AF 10 fps 11 fps
Top Active D-Lighting option Extra High Extra High 2
Top movie resolution 1080/30p (24Mbps) 1080/60p (42 or 24Mbps)
Interval shooting limit 999 shots 9999 shots
Ethernet 100Mbps 1000Mbps
Memory cards
CompactFlash, XQD
Batteries used EN-EL18 EN-EL18a, EN-EL18
Battery life (CIPA) 2600 shots 3020 shots*
* with EN-EL18a battery

As you can see, everything on the D4s is an improvement to the D4 - at least on paper.

Autofocus

The biggest news, in terms of autofocus, is the D4s' ability to continuously focus at the camera's highest frame rate (a feature limited to 10fps on the D4). Another way of looking at the 'decreased viewfinder blackout' that Nikon is promoting is: 'having the mirror in the position that allows AF, for longer.' As such, we suspect the redesigned mirror mechanism plays more of a role in allowing the extra 1 frame per second focusing, as the camera's more powerful processor. What it certainly hasn't changed is the AF sensor itself, so it's mostly a case of making the most of what's already there, rather than radically overhauling the camera's capabilities.

Although it doesn't detail or quantify the changes, Nikon promises that the autofocus algorithms have been tweaked and improved - which could prove to be the most significant change. The only example of this given is that the AF lock-on is now slightly less easily distracted by objects crossing in front of the intended subject.

Beyond this, there are a couple of small feature additions, but no claims of any fundamental re-thinking. The D4s now includes a focus point mode in which the AF point will switch to the nearest comparable position, as you rotate the camera - jumping to the top left position in portrait orientation if you'd selected the top left point while the camera is in the landscape orientation, for instance.

There's also a Group AF mode, in which the user can specify a cluster of five points to focus on, rather than having to choose a single point. The existing system did allow you to specify the number of surrounding points that the AF system would consider, but the new mode gives much greater weight to the four points adjacent to the selected AF target. As with many of the AF behavior tuning options in cameras at this level, we suspect the benefit of this feature will be specific to a certain shooting situation, and its value will only be revealed when applied to that situation.

Movies

Perhaps the biggest surprise to us is how little the D4s has gained in terms of movie functions. The headline change is that the D4s can now shoot 1080 video at frame rates of 60p and 50p (at bitrates of around 48Mbps), but beyond that, there's not much that's changed. There's been no improvement in whatever limited the D4 to 20 minutes of video recording: the D4s hits a similar limit, with high bitrate 60p restricting the camera to just 10 minutes of footage capture.

The D4s can now adjust audio volume as it records, but there are no additional features to support movie capture: no focus peaking or zebra, and no additional high bitrate settings for the frame rates already offered by the D4. Unlike existing Nikons, the D4s can now simultaneously output uncompressed video over HDMI and record to internal memory cards.

Overall, though while the D4s makes sense as a camera head - buried in a rig with external monitors and recorders bolstering its capabilities - it's hasn't taken any big steps towards being the modern photojournalist's stills and movies all-rounder. This isn't to say the D4s isn't a credible camera for using video; just that, after years of manufacturers insisting on the importance of video as a tool for working photojournalists, we're surprised to see so few changes or additions have been made.