The image quality may be above average for what you're paying, but not much more.
Practically speaking, the results are... mixed. The back camera certainly punches above its weight. We took a few shots in low lighting that we didn't think we'd pull off. Also, shot-to-shot lag is minimal and the shallow depth of field helped emphasize subjects in the foreground. Colors are generally accurate as well. With that said, the R819's photography prowess clearly doesn't approach that of advanced cameraphones like the HTC One, iPhone 5s or Lumia 1020. There isn't much dynamic range, leading to blown-out highlights and overly dark shadows. Noise and motion blur appear in scenes where we wouldn't necessarily expect them, even when using appropriate photo modes. The image quality may be above average for what you're paying, but not much more.
Things get better with the front camera, if only because the expectations in this area aren't as high. The 2-megapixel camera produces fairly sharp, color-accurate photos in well-lit situations, but its chief advantage is an 88-degree wide-angle lens that helps fit extra people into the frame. It's there for selfies and video chats, not artistic statements.
Shutterbugs won't get a lot of control, regardless of which camera they're using. Oppo's custom camera interface on the R819 doesn't let you change ISO sensitivity, white balance or other settings. You'll have to lean on the nine scene modes to get better results. Outside of the normal and auto-scene selections, our favorite mode is HDR (high dynamic range); as long as you keep the phone steady in mid-capture, it brings out more detail without going overboard. There are also occasionally helpful night, sports and sunset modes. A sweep-based panorama mode can be handy for landscape shots, although it sometimes messes up the frame-to-frame stitching. We wouldn't make much use of Beauty Shot and Rewind, the two most advanced camera tricks. The former didn't do much to clean up our skin imperfections, while the latter's BlackBerry 10-like ability to pick out facial expressions is only helpful in those portraits where a perfect smile is crucial.
Video capture may be the R819's strong suit. In daytime, 1080p videos from the rear camera are clean and sharp. Night movies are prone to grain and blurring, but you can at least see subjects clearly if there's a trace of light; that's an improvement over other phones, which sometimes leave things shrouded in darkness. The dual microphones generally produce clear audio, although they didn't do much to reduce wind noise.
Performance and battery life
Remember when we said that many Chinese smartphone builders keep costs down on big phones by using lower-end processors? Here's where that scrimping and saving comes into play. The R819 runs a quad-core, 1.2GHz MediaTek MT6589 that doesn't compete well against modern dual-core chips like the Snapdragon S4 Pro inside the Sony Xperia SP, let alone the quad-core Snapdragon 800 powering the Nexus 5. Looking solely at CPU-driven benchmarks, the Nexus 5's lead ranges from 62 percent in CF-Bench to 89 percent in Quadrant. The gap is even wider in graphics-heavy tests like 3DMark or GFXBench, where the MediaTek processor's PowerVR SGX544MP video core struggles. If you're buying a phone for bragging rights, the R819 isn't for you.
Don't rule it out just yet, though. Subjectively, Oppo's phone is still fine. The interface flows smoothly; web pages load reasonably quickly; and there's seldom any trouble with multitasking, even with a modest 1GB of RAM. If all you're doing is checking Twitter, posting to Instagram and making the occasional phone call, you'll be more than satisfied. The performance limits are mostly apparent in games. An older 3D release like Riptide GP is fine, but modern, graphics-intensive titles like Real Racing 3 choke on the R819's hardware.
You may forgive the low performance after witnessing the extraordinary battery life. The R819's 2,000mAh lithium-ion pack only managed to last six hours and 15 minutes in our rundown test, which loops a 720p video with the screen at half brightness while email, Facebook and Twitter run in the background. That doesn't tell the whole story, though. In practice, you won't usually worry about plugging in. We still had half a charge left after a full day of use that involved a 15-minute call, taking and uploading several photos, occasional web browsing and social networking. Simply put, the longevity is outstanding for such a thin device -- it's proof that you don't need a giant battery for your phone to go the distance, just an efficient chip.
You will have to give up strong cellular coverage for that privilege. Data on the international model is limited to basic HSPA (850/900/2100). That supports many providers around the world, including AT&T and bigger Canadian networks, but it excludes T-Mobile USA and others on less-common frequencies. And if you've forgotten how slow HSPA-based 3G is, you'll be reminded with the R819. Downloads on Telus' Ottawa network would regularly peak at about 1.1 Mbps; uploads didn't get better than 280 Kbps. The cellular speeds are frankly disappointing when the MediaTek chip theoretically supports up to 42 Mbps HSPA+ data, and we can't see many in LTE-friendly areas giving up that much bandwidth to get several more hours of use.
At least the call quality is superb. Both inbound and outbound voices were loud and clear. The speakerphone isn't anything to write home about, but it gets the job done in a mostly quiet room. There's a small nub on the back that keeps the rear speaker audible while the phone is resting face-up on a table.
If you hadn't guessed by now, the Nexus 5 is the elephant in the room -- you simply can't discuss the R819's competition without mentioning Google's similarly priced flagship. And to be frank, it wins the comparison battle by a wide margin. Oppo's phone has superior battery life and a slimmer profile, but the Nexus 5 is faster, supports quicker LTE data, shoots better photos and carries a sharper display. It's also a smarter purchase if you like to stay on the bleeding edge of software, since Google writes its own OS updates. Unless you absolutely need the R819's extra running time or live in a region where the Google Play Store doesn't sell hardware, the Nexus 5 is the better deal.
Other phones don't challenge the R819 so much as sandwich it; they either promise a lower price for comparable hardware, or superior performance at a similar cost. BLU Products' Life One mates the same efficient MediaTek CPU with a bigger screen and sharper cameras at a lower $299 price. Motorola's Moto G won't be available in the US until January, but its $199 16GB variant promises tremendous savings while sacrificing little. It may even claim a performance lead. Sony's $380 Xperia SP, meanwhile, delivers both a faster processor and a more advanced Exmor RS camera for its $30 premium. It's hard to make an argument for Oppo's smartphone when it's neither the most capable in its price group nor the most affordable.
We know what you're thinking: The R819 doesn't stand a chance in such a heated smartphone market. And you're right, to some degree. In regions like North America and Europe, where it's relatively easy to buy a Nexus 5 for the same $349, there's little reason to give Oppo's phone a close look. It's a fish out of water; while this combination of CPU and 3G wireless is quite common in China, it doesn't hold a candle to the Snapdragon chips and 4G that are common elsewhere on the planet. If the company is serious about international expansion, it will want to do more than just export its domestic lineup with no major changes in tow.
Even so, there are a few reasons to consider the R819 over its peers. If you live in a country where the Nexus 5, Life One and Moto G aren't options, Oppo's device is a far more tempting prospect -- it's one of the cheaper devices at its size. It's certainly not a bad phone if you can live with the performance, since that slim design and epic battery life are hard to beat. We ultimately enjoyed using the R819. It's just not a great fit in places where there are more compelling alternatives.