The Nikon D4 has some fairly big shoes to fill. Its predecessor, the 12.1-megapixel Nikon D3S was a veritable low-light killer, capable of shooting crisp images even in poor lighting without a flash.

But the D3S had one major deficiency: While its 35-millimeter “full frame” CMOS sensor took great pictures in a range of conditions, the paltry 12.1MP of resolution meant you couldn’t significantly blow those images up or crop in too deeply without losing detail.

Nikon seeks to solve that issue with the new D4 by increasing the resolution to 16.2 megapixels while, at the same time, maintaining the camera’s killer instincts when shooting in low light. That’s not easy. Adding more pixels to the D4′s 36 x 23.9-millimeter imaging chip means those individual pixels have to be smaller, which gives them less surface area to absorb light. But after shooting with the D4 in a range of tough conditions, it’s clear this camera is a master of the dark arts.

A photographer friend and I took the D4 to one of the more challenging environments we know: the shadowy depths of New York City’s Grand Central Station, where we photographed two dancers in an improvised duet. Because we didn’t have a permit for the shoot — permit? We don’t need no stinkin’ permit! — and didn’t want to attract attention, we both shot quickly, on the fly and without a flash.

To increase the sensitivity of the imaging chip to pick up the weak available light in the station, I cranked the camera’s ISO up to 12,800 and was able to capture impressively clean images of the dancers with only a few traces of digital noise in the shadow areas. Meanwhile, the D4′s quick and accurate 51-point autofocus system was tack sharp, even when capturing dancers dipping and spinning across the train platform.

Along with its impressive low-light chops, the D4 exhibited blazing speed overall, firing off 10 frames per second (or 11fps when the focus and exposure were locked on the first frame). We were able snag several winning images before the police ejected our party from Grand Central. The camera is about as quick to start up and shut down as the previous model — which is a good thing, because the D3s was fast — and exhibited no discernible shutter lag.

As a video camera, the D4 also impressed. After the escapades in the train station, we shot a gorgeous 1080p HD movie of a bartender making us some well-earned margaritas. The D4 has a one-touch video button that eases the transition to moving images. Though my hands were a little shaky from the tequila, the D4′s video mode showed minimal “rolling shutter” — the Jell-O effect that occurs when you pan too aggressively while shooting HD video with a CMOS sensor. I was disappointed in the audio quality, though. Since the D4 only has a built-in monaural mic, if you want better sound, attach a stereo microphone to the camera’s stereo mic jack to record more fully.

WIRED Separate 91,000-pixel sensor is dedicated to light metering, autofocus and recognizing and adjusting to different shooting scenarios. More rounded and ergonomic design with lower pentaprism still lets you see 100 percent of what you’re shooting through the viewfinder. Back-illuminated buttons help you set the camera in dark conditions.

TIRED Second card slot is Sony’s new and expensive XQD format. Built-in mic only offers mono sound. Burst shooting is a frame slower per-second than the competing Canon 1D X.

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The 22.3-megapixel Canon EOS 5D Mark III captured some of the cleanest images I’ve seen from a DSLR when shooting in low light at high ISOs. That’s no small feat. Cameras such as the 5D Mark III’s predecessor — the 5D Mark II — and the 16.2MP Nikon D4, are designed as low-light assassins, with large, full-frame sensors approximately the same size as a frame of 35-millimeter film.

That the Canon 5D Mark III does so well in so little light is all the more impressive because the pixels on its 36 x 24-millimeter CMOS sensor are smaller than those in the lower-resolution D4. Tinier pixels have less surface area for absorbing light and should, theoretically, stumble more easily in the dark. Not so with the 5D Mark III.

Even at ISO 25,600, which makes the camera’s chip so sensitive to light it can almost “see” in the dark, my still-life test shots with the Mark III had few crunchy, digital artifacts — aka “noise” — in the shadow areas. The results carried over to real-world usage in an outdoor portrait session I shot with the 5D III.

The camera’s ability to shoot crisp images in only available light — and intentionally murky light at that — allowed me to put away my external flash and keep my subject looking soft and natural. It’s not that you can’t create a similar effect with a flash if you know what you’re doing, it’s just that with the 5D Mark III, it’s often unnecessary.

On the downside, when I zoomed in, I saw slightly less detail than competing cameras such as the Nikon D4. The 5D Mark III’s Digic 5 processing engine seemed to smooth out the rough edges of my shots. This was disappointing considering the 5D III’s 22.3 megapixels of resolution should have allowed me to make nearly billboard-sized prints from my photos without sacrificing image quality.

In decent natural light or in controlled studio lighting though, the 5D III’s photos were fabulous, with my portrait session producing creamy skin tones and attractive colors. If you photograph weddings, parties, or people in general, this is the camera for you. The 5D III’s 6-frames-per-second continuous shooting and improved durability with weather resistance are a step up from the previous model. I photographed a model moving through quick poses outdoors under threatening skies without worry.

The 5D III’s HD video skills have improved, too, with more frame speeds and compression options that allowed me to experiment with different looks and files sizes. While the previous 5D model was a truly groundbreaking videography tool upon arrival, there’s not as much of a revolutionary shift evident here. But I loved the high-quality HD movies I shot, which were crisp and nearly artifact-free, thanks to the better processing from the 5D III’s Digic 5+ chip.

WIRED In-camera HDR (High Dynamic Range) feature combines three shots into one image with better exposure. “Silent” shooting mode helps capture stealthy candid portraits. Rank photos in-camera with one to five stars, then carry those ratings over to Adobe Lightroom, Adobe Bridge and Apple Aperture. Same 61-point (41-cross-type-point) autofocus system as top-of-the-line Canon 1D X.

TIRED Only slightly more resolution than four-year-old previous model. Starting price nearly $1,000 higher than predecessor. Built-in mic only offers mono sound.

Photos courtesy of Canon, Inc.

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The Basics

What makes a DSLR “professional”?

There aren’t hard and fast rules, but several features set these cameras apart, like beefy alloy bodies, rubberized handgrips, and dependable shutters that can be fired hundreds of thousands of times without a hiccup. They also combine zippy, multipoint autofocus systems with the ability to fire upwards of 10 frames per second, meaning they can track and capture action in ways not possible with consumer models.

Read our reviews:

Canon EOS 5D Mark III

Nikon D4

Why is it always Canon versus Nikon?

There are other camera companies selling DSLRs—notably Sony, Pentax, and Olympus. But when it comes to professional, $2,000-plus cameras, Canon and Nikon control 97 percent of the market, due mostly to their early dominance in 35 mm, which locked most pros into their lenses. And it’s clear that they care only about each other: Though their previous-generation pro-level shooters were on the market for years, their four newest models, featured here, all have release dates within just months of one another.

How important are megapixels?

No number is more misunderstood or abused than pixel count. What matters more is pixel size, and that’s dependent on sensor size. In two cameras with the same megapixel count, the one with the bigger sensor should produce better photos. In models with equal sensor sizes, the one with fewer megapixels should perform better in low light or at high speeds, and the one with more will capture better detail—if the lighting is good.

Buying Advice

Think about how and where you’ll be shooting. The action and variable lighting of reporting and sports photography require the more expensive models with fast motors and fat pixels; the controlled environment of studio work is very friendly to higher-pixel-count models.

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