Sony’s new a7R II is a shot across the bow of Canon and Nikon. Spend anytime with Sony’s engineers, and you’ll hear them describe their new system with the term "disruptive." Based around a new Sony-designed sensor, the a7R II is a clear sign that Sony has their competitors in their sights and is gunning for their market share. The spec sheet for the a7R II reads like a brochure for "why mirrorless is the future" and Sony is quick to point out that many of the key features in the camera—electronic first-curtain shutter, eye-detection AF and on-chip phase detection, among them—aren’t possible with DSLRs.
The questions that arise, then, are "Does it deliver on Sony’s promises?" and "Does it unseat the DSLR?" (See "The DSLR Is Still King" in this issue.)
The answers are "yes", and "may-be"—depending on what type of photography you do.
Feature-Laden
The a7R II is the fifth camera in the Sony a7 series, and is the second of the Sony cameras with the second-generation "II" moniker. The a7 II, which was released just nine months ago, included a lot of the technological innovations that have made their way to the a7R II. Like the a7 II, the a7R II has in-camera five-axis stabilization, a wide on-chip phase-detection AF system and more, but the a7R II ups the ante considerably with several new and impressive features.
The most interesting development in the a7R II is the new 42-megapixel, full-frame sensor.
As a general rule in digital photography, the more pixels a sensor has (all else being equal), the worse the camera performs in low light. Sony wanted to change this, so they created a new sensor for the a7R II with a technology called Backside Illumination (BSI) to dramatically increase the sensitivity.
The result is a 42-megapixel camera with an ISO rating up to 25600, expandable up to 102400, while the competing 50-megapixel Canon EOS 5DS has a top ISO of 6400 and the Nikon D810, 12800. That high ISO rating enables photographers who would previously have had to go to a low-megapixel camera (like the a7S) to get good ISO performance to instead capture images with huge resolution.

This full-frame BSI sensor is only in Sony’s a7R II, meaning that the previously released a7 II doesn’t use the tech. It still has a wide ISO range (thanks to the lower-megapixel resolution), but consequently doesn’t have the advantages of the BSI technology—shooters will need to wait for a third-generation system for the new chip design.
The a7R II also improves upon the autofocus in the a7 II, adding an AF-A mode that automatically selects from AF-S or AF-C, depending on the scene, and a lock-on AF mode that’s incredibly useful. In this mode, photographers can select a subject and then pan the camera, and the focus point will stay locked on the original subject.
The a7R II also has eye-detection focus (while the a7 II has face-detect), which I found to be incredibly accurate—more accurate than their (or anyone’s) face-detection system and more accurate than I’ve ever seen on a DSLR. This is another case where technology has begun to supersede the performance of a photographer.
The heart of the AF engine is an on-chip phase-detection system with 45% coverage of the sensor. This system is fast enough that it allows lenses from Canon (when attached with an adapter) to perform at a speed comparable to native Sony glass.
The a7R II also introduces an electronic first-curtain shutter, which can be activated at anytime and enables completely silent operation. For wedding photographers and photojournalists, this feature could be a lifesaver, as it’s possible to capture images without any sound at all.
4K And More
The a7R II also leaps ahead of the video-centric a7S (and ahead of all other cameras currently on the market) with its 4K video capture. Other cameras that are capable of capturing 4K use a technique called "pixel-binning" in order to save time processing the massive data from a sensor. Pixel-binning simply means that the camera doesn’t read each pixel of data, but skips some pixels and interpolates the data from the pixels the camera does read.
The Sony a7R II instead reads every single pixel for its 4K video, which can result in superior video image quality. Unlike the a7S, which requires an external recorder for 4K video capture, the Sony a7R II can write to SD cards.
This instantly makes the Sony a7R II one of the most desirable cameras in 4K video capture.
In The Field
For the shooter familiar with the performance of the original a7, the a7R II is a completely different experience. While the a7 wasn’t slow, per se, it never performed as well as even a mid-level SLR in terms of AF speed. It was a great camera for the photographer doing portrait work, but you’d never try to capture adventure sports with it.
The a7R II is (like the speedier a7 II) a whole new creature. It focuses instantly, easily as fast as the top DSLRs and, in some situations, it focuses more quickly and more accurately. Because the sensor is always active in a mirrorless camera in order to provide an image in the LCD or EVF, the phase-detection system can do things that DSLR systems cannot, such as real-time eye-detection focus.
One other advantage to having the phase-detection sensor on the chip is that the sensor is able to make use of all available light for focusing. With a DSLR, light is reflected to a separate sensor (via the reflex mirror) and that chip usually operates stopped down to ƒ/4 or ƒ/5.6 (depending on the camera). With an on-chip mirrorless system like that in the a7R II, the sensor can operate at the maximum aperture, which gives it a low-light focusing advantage.
These advantages are something that Sony takes pains to mention; it’s the secret sauce in the mirrorless world and it’s key to Sony’s plans to chip away at the competitors. The company has looked at the limitations of the DSLR world and is innovating in order to make mirrorless cameras not on par with them, but in a class above.
In The World
Of course, the success of Sony’s world-dominance plans depends on the operation of the system in real professional applications. While there are some pretty compelling advantages to using a mirrorless system, there are still some limitations. (We cover these more in depth in "The DSLR Is Still King.")
One notable area where the a7R II falls short, as do all the a7 cameras, is the speed with which the camera clears out the buffer and returns to operation. Because of the small size of the a7-series body, there’s not as much room inside for things like processors and buffer RAM as in cameras like a Canon EOS-1D X or Nikon D4S, and the internal mechanics are smaller, as well.
As a result, the a7R II, like the a7 cameras before it, isn’t as fast as a top-end DSLR—you’re maxed out at 5 fps vs. the 11 fps of a pro DSLR, and the buffer fills up more quickly and takes longer to clear than a pro DSLR. Even after a few shots, it’s necessary to wait a few seconds for the files to write to the card before it’s possible to review images or change settings.
The Sony a7 system also uses a relatively small battery, which has a shot count of just a few hundred images, where a pro-level DSLR can capture thousands of images before needing to swap out the battery.
Those shortcomings aside, the Sony a7R II is a remarkable camera, and it produces remarkable images, especially when paired with glass like the Zeiss Batis lenses (see the sidebar). Sony designed all of their lenses to perform well with high-resolution sensors
, and the a7R II brings out the best in a good lens.
In my tests, the Sony a7R II exceeded expectations. While the Sony a7 and a7R I’ve shot with felt, at times, pokey, the Sony a7R II always felt as if it was operating at light speed. Focusing is lightning-fast and accurate. Portraits—especially those when eye-detection focus is active—are sharp, and it’s much faster to compose a shot with a subject knowing that the camera can pick out and track their eye.
Color fidelity and reproduction are likewise excellent. Combine the a7R II with high-resolution lenses, and the result is an incredibly sharp, accurate and detailed image.
High ISO
With the new backside-illuminated sensor and the claimed ISO performance, naturally I had to take the camera out in the dark.
For handheld streetscapes late at night, I increased ISO, capturing the buildings and streets between ISO 16000 and 32000, and found that the amount of noise at this range is comparable to many other systems at ISO 1600. There’s very little grain, very little to indicate that the street corner image was shot at an ISO that—if available on most other profession cameras—would produce an image that was for all purposes useless in a commercial application. The performance is an order of magnitude better than the Canon EOS 5DS and Nikon D8100, the closest competitors for this resolution. The low-light performance is also vastly better than all of Sony’s other a7 cameras, aside from the ultra-high-sensitivity a7S. The a7S achieves its high sensitivity by using a low-resolution sensor, while the a7R II has both sensitivity and resolution.

This night landscape of Portland was also shot at ISO 16000, handheld at 1/125th of a second at ƒ/2.0 and gave an image comparable to many I’ve seen at ISO 2000, noise-wise. That’s a 3-stop improvement in light performance, which is incredible.
In short, the a7R II lives up to its claims for ISO performance, quickly becoming the best-in-class at the resolution, and better than many other cameras at lower resolutions.
Sports And Events
The a7R II isn’t marketed at sports photographers, due to the high resolution of the sensor and the speed with which the camera processes images. At 42 megapixels and 5 fps, this camera isn’t designed to keep up with a pro DSLR in frame rate, and the experience for a Sports Illustrated shooter trying to capture something as fast as the X Games would be frustrating, mostly because of the time it takes the camera to process images before shots can be reviewed or before the menu can be accessed.
That said, there are some very compelling applications for sports photographers here, especially with the low-light performance. While the a7S has fantastic high ISO quality, it doesn’t have the five-axis stabilization of the a7R II, nor does it have the ability to record 4K internally. That makes the a7R II the must-have camera for the sports shooter doing a mix of video and stills.
During a press event sponsored by Sony, I had the opportunity to test the a7R II as a sports camera, thanks to several high-speed subjects they had on hand. With mixed martial arts fighters, breakdancers and acrobats as subjects, I switched the camera into high-speed frame rate and tested the various focus modes.
All of the focus tracking kept up with the speed of the action and tracked the subjects at least as well as the DSLRs do. There was more lag time between each shot than with an optical DSLR, meaning that the a7R II blacked out momentarily between frames as the shutter triggered, but the AF system continued to focus and perform.
The big drawback for sports—or even for wedding, news and event photography—is the time between when a batch of images are captured and when they can be played back or settings can be changed. Waiting several seconds to review an image after just a few RAW files are captured is a huge issue for photographers who are used to checking their framing and lighting in-camera.

Conclusion
The a7R II isn’t a perfect camera, but it’s the best camera that Sony has ever made, it’s the best mirrorless camera available, and it’s the first camera that truly challenges the DSLRs.
That Sony managed to get so much performance out of a sensor this large and still maintain image quality that’s on par with the best DSLRs is telling. Their goal is clearly to someday make a mirrorless camera that beats the DSLR in every category. The a7R II isn’t that camera, but it’s certainly the closest camera the industry has ever seen.
You can reach David Schloss on Twitter or Instagram @davidjschloss