Nikon's $6000 D4 might just be the new most deadly lightstalker around with a new 16.2-megapixel full-format CMOS sensor that has (relatively) gigantic 7.3-micron pixels (bigger than Canon's new 1 DX). And it shoots at up to ISO 204,800. Did I mention it's better than the D3s in almost every way?
With an expanded ISO range from 100 to 204,800 , it's a stop beyond the D3s on both ends. More importantly, it takes the range where you can expect a clean shot up to around 12,800, roughly twice as excellent as the D3s.
It's got a 91k pixel 3D color matrix meter and 51-point AF tracking system (which has 15 cross-type center points, and fun tricks like tracking up to 16 human faces simultaneously). AF also retains its orientation when you change from landscape to portrait, so your focus won't shoot off to the corner. Autofocus in general also gets a bump, down to -2EV, a full stop slower than the D3S. It shoots fairly fast, despite not having a dual image processor like Canon's 1DX—10fps even in RAW (though if you lock AF and AE, you can nudge it to 11fps).
But maybe the most important upgrade of all, at least for some where Nikon is concerned, is the D4's video powers. So yes, it shoots in 1080p at 30 or 24fps (or 720p at 60fps) . But it now uses B-Frame data compression, so you can record h.264 clips for up to 20 minutes continuously. You also have full manual control over exposure while shooting (like previous Nikon DSLRs, you can use AF while shooting, too). And, what might be killer for some people: totally uncompressed HD output through the camera's HDMI port, along with remote shutter operation for video recording and power aperture, for totally silent adjustment while shooting. Oh and for some extra reach, you can switch from full-frame to Nikon's DX format (a 1.5x crop factor) or to a 2.7x crop at the standard 1920x1080 resolution, giving you essentially free telephoto zoom powers while keeping your video in full HD. Nikon's promising "less instances of rolling shutter distortion" to boot.
Speaking of light, it's lighter. Or at least it feels that way. It's the first thing we noticed when we picked it up. And it didn't come at the expense of build quality, since the D4 has the same magnesium alloy chassis build, just trimmed down in areas where it could afford to go on a diet.
It's got a new 3.2-inch 921k dot LCD (up from 3 inches on the 3S) and an Ethernet port for better connectivity, though we're not sure if it's quite as capable as the 1DX's Ethernet hole.
Ergonomics and usability have improved some, too. There are now two AF buttons for when you're shooting in portrait, and all buttons are backlit, for better usability in the dark. The D4 has two memory card slots, which are optimized for standard cards as well as the new CompactFlash XQD memory cards, making it the first pro camera to adopt the new format.
It's good to see Nikon taking aim at videographers who have felt a little out in the cold in refreshes past.