As mentioned on the previous page, the D4s has just a few minor cosmetic changes compared to the D4. Here's a closer look at some of the most important controls.
The D4s' optical viewfinder is unchanged from the one on the D4, which means that it has 100% coverage and a magnification of 0.70x.
The switch at the upper right deploys a cover that prevents incident light from getting in when you're not shooting with your eye to the viewfinder.
One of the few cosmetic changes on the D4s can be seen in this photo. The AF-On button is now easier to press, while the AF-point selector below it is now made of plastic instead of rubber (which Nikon says improves its 'feel').
To activate live view, simply press the button located to the lower-right of the LCD. To switch between still and video recording use, well, the switch.
The D4s retains the same Pv (DOF preview) and Fn as its predecessor. Both buttons are customizable, and the ability to switch between FX and DX crop modes can now be assigned to either.
At the top-right of the D4s' front plate you'll find the self-timer lamp, as well as the flash sync and 10-pin ports. The latter is used for connecting Nikon's optional remote controls.
On the left side of the D4s are six more ports. They include a peripheral connector, USB, headphone, microphone, Ethernet, and HDMI ports.
Ethernet support on the D4s has been upgraded from 100Mbps to 1000Mbps (Gigabit).
Just at the right edge of the back plate are the camera's dual memory card slots. The one on the left accepts XQD cards, while the slot on the right is for CompactFlash. Ultra-high speed UDMA 7 cards are supported by the latter.
The D4s uses the new EN-EL18a lithium-ion battery, which allows you to take a whopping 3020 shots per charge (measured with the CIPA standard). That's a 15% improvement over the D4 and its EN-EL18 battery (which also works on the D4s).
There's no doubt that the Nikon D4 was a top-notch professional DSLR. Perhaps that's why the D4s doesn't feel like a very exciting upgrade, despite the countless tweaks to both design and features, performance, autofocus, and movie features. Perhaps the feature that working pros will appreciate the most is the increase in battery life compared to the D4. The 'newly designed' CMOS sensor and image processor also allowed Nikon to squeeze in an extra stop at the top end of the ISO range.
Seeing how the D4 was already so strong in terms of still quality, Nikon focused more of its attention on video. You can now record at 1080/60p (though not for terribly long), use auto ISO so shutter speed and aperture are not disturbed, and output uncompressed video over HDMI while you're recording to an XQD or CF card. Despite those improvements, the 10 minute recording limit and lack of focus peaking and zebra pattern leave something to be desired.
Current owners of the D3 and D3s will no doubt find the D4s a worthy update. Whether D4 owners will upgrade to the D4s is less clear, as the major changes are specific to certain shooting situations, many of which were brought up by professionals who've been living with the D4 since it was made available around the time of the 2012 London Olympics. If its exposure at the more recent Winter Olympics is any indication, it's safe to say that you'll be seeing a lot more of the D4s at major sporting and news-making events.