Some phones try to be fast. Others try to be cheap. However, the R5 is all about thin-ness.
It's the thinnest phone to date, if you're willing to forget the little bit of camera lens that sticks out from the rest of the body by just a smidge. At 4.85mm thick, it's only about as chunky as two After Eight mints sitting on top of each other.
Of course, unlike phones that are out there to offer the best performance or the best value, we're left wondering: is there a benefit to the Oppo R5 being this thin? We like a thin phone, but your perception of something being thin is as much to do with its shape as its pure millimetre count.
And, as is to be expected, there are trade-offs. Battery life takes a pretty significant hit and the Oppo R5 doesn't even have a 3.5mm headphone jack. Obsession can lead to greatness, but perhaps the R5's obsession with thin-ness isn't actually that healthy...
Size 0 Model
If you took an iPhone 5S (remember those?), stretched it a whole bunch and gave it a fierce going-over with a rolling pin, and managed not to crack it into a million pieces, it might look like the Oppo R5. It has a hard, dense-feeling aluminium and steel body with white accents on the top and bottom of the rear.
Around the front, though, there's much less of an iPhone-apeing flavour. For one, there's a trio of physical soft keys that, unusually for a phone this pricey, don't light up.
It looks like a pretty expensive phone, but how does the Oppo R5 feel? Well, thin, of course. However, it also feels a bit severe, thanks to the relatively sharp contours of its sides.
Next to the smooth-backed Galaxy S5, it's not entirely snug in your palm. The Oppo R5 doesn't have supremely skinny bezels either - as such its handling is comparable to other slim 5-odd inch phones.
The benefit of that searingly thin body is definitely partly visual, but we're happy with how the Oppo R5 feels. After all the fuss made about the 'bendy' iPhone 6 Plus, we tried to see if we could flex this phone at all with our hands. We can't. It feels tough, hard and just as well-made as phones from bigger names. It's partly down to the use of a tough steel inner frame.
READ MORE: Apple iPhone 6 Plus vs Samsung Galaxy Note 4
But it isn't overly flexible in use, either. It doesn't have a memory card slot or even a headphone jack. These are all casualties of the Oppo R5's caring about the size of its waistline more than pretty much anything else.
With 16GB of memory, the R5 doesn't really make a great portable music or video player as there's just not enough room, and the headphone jack issue is very, very annoying at times. Perhaps this is just the tip of a Bluetooth-only future for phone 'phones, and in the box you get an adapter that plugs into the microUSB jack and gives you a headphone output, but we've found ourselves missing the normal headphone jack like a departed best friend.
And what if you lose the adapter? It's just another thing to worry about, and it's not as if you'll want to keep this 10cm-long cable sticking out of your phone 24/7. You could keep it attached to your headphones, but that's not good if like us you also listen through a laptop or another sources at times.
Being so thin does not, thankfully, affect the screen. The Oppo R5 has a 5.2-inch Super AMOLED display.
While we're hurtling towards a time when QHD screens will be the norm for high-end phones, this one has a 'normal' 1080p display. It's more than sharp enough to be called 'Retina' grade, and the size is easily big enough to make watching a bit of Netflix on the way to work a joy.
As is common with OLED-type screens, colours are oversaturated a bit. But not to the extent that red balloons look like they're about to jump out of the screen and strangle you. They're just no 100% accurate.
Side-by-side with the LCD-screened Oppo N3 (review coming soon), you can see the Oppo R5's colours don't have the same relaxed, natural look. Instead, though, the OLED display gets you fantastic contrast, with images looking poppier than an 80s boyband revival festival in just about all conditions from dark rooms to bright sunny days.
Oppo plasters a plastic screen protector on the phone to try and keep it in good nick, and it doesn't seem to have any degrading effect on image quality. Plus, as it's applied in the factory there's no chance of those bubbles you can't avoid when applying a protector yourself.
READ MORE: Oppo N3 hands-on review
ColorOS vs Android
The eagle-eyed among you may have already noticed the Oppo R5 doesn't use a totally generic version of Android, but a custom take.
Oppo calls it ColorOS, and like every other manufacturer's Android skin it just fiddles with how Google's mobile OS looks and feels a bit. Desperate to make its mark, ColorOS cuts out the app menu you usually get in Android, relying 100 per cent on the home screens like Apple's iOS.
However, it has a tendency to make your phone look and feel a bit cluttered if you're not careful. And we're not in love with this UI's look either. Granted, it's not a million miles removed from any other take on Android, but lacks the cosy lifestyle look we saw recently in Android 5.0 Lollipop on the Nexus 6.
The style is much closer to what you see on the phones of another Chinese handset maker, Huawei. As well as getting rid of the apps menu, the Oppo R5 offers themes that re-skin the device with different wallpapers and icons. They must really love them in China, because other phone makers stopped offering them about a decade ago. It's quirky, but if you're after something a bit different, perhaps that's not a negative.
There are a few extra features, too, such as the ability to launch apps from standby simply by drawing a shape on the screen.
It's also a bit, well, buggy. The Oppo R5 has enough power to keep the lights on in a small village, but we did notice the odd laggy moment that just wouldn't be there in a better-optimised phone. This is probably something that Oppo will iron out over the next few updates, but there's no telling how long that might take.
How powerful is it? The Oppo R5 has a Snapdragon 615 CPU, an 8-core processor that while a step below the Snapdragon 801 of the Note 4 in terms of raw power, is a bonafide 64-bit CPU. In the Geekbench 3 benchmark tool it scores 2505 points - fantastic for what is a mid-range CPU.
It also has a decent 2GB of RAM. There's enough power to take on the world here, but the Oppo R5 feels like it's held back a little by its own software.
READ MORE: The 35 Best Free Apps for Android
Operating System: Android 4.4.4 with ColorOS
Screen: 5.2in Super AMOLED with 1920x1080 resolution (424ppi)
Processor: Octa-core Snapdragon 615 @ 1.5GHz
Storage: 16GB (not expandable)
Camera: 13MP rear, 5MP front
Connectivity: NFC, Wi-Fi, 3G/4G, Bluetooth 4.0
Dimensions: 149 x 75 x 4.9mm
Oppo has really stuck its oar into the camera software. But it doesn't backfire here. The Oppo R5's camera app is pretty easy to use, the thing is pretty snappy to take photos and there are plenty of modes on offer.
There are a few 'installed' as standard, but you can tool-up the app with plenty more. There are ultra macro modes, one thats ultra-high res images by combining multiple exposures, HDR, long exposure, GIF animation and even RAW capture. The Oppo R5's camera app makes it look as though you're installing these extra modes, but really are just being enabled and disabled - you don't need an internet connection to do it. There's as much, or as little, control as you like on offer.
Underneath all the neat software extras, the hardware of the Oppo R5's camera is sound but not world-beating. It has a 13-megapixel Sony IMX214 sensor, the same used by several other phones including the OnePlus One, the Nexus 6 and Xiaomi Mi4.
Among these Sony sensor brothers, it's one of the better performers. Speedy and with colour reproduction that's normally spot on in good lighting, with only a slight tendency towards overexposure causing minor issues. The white balance is also often on the warm side with indoors lighting.
But in poor lighting, photos get pretty noisy and colour saturation takes a dive, because the phone prioritises speed over absolute image quality. There is a mode to bump-up saturation in night photos, though. The Samsung Galaxy S5 produces slightly better, sharper photos, but the Oppo R5 certainly isn't bad.
The front camera isn't too shabby either. It has a 5-megapixel sensor, making it one of the new wave of selfie-conscious phones. However, like a good deal of these phones, you don't really get twice as much detail from a good 2-megapixel camera. These selfie cams tend to have pretty dinky sensors so unless you're shooting in good lighting, everything starts to get a little bit fizzy.
The front camera is also where you notice one of the Oppo R5's obvious bugs. A fraction of a second after opening the app, the camera preview screen just goes black, leaving you to shoot blind. It'll still take photos, you just have to do so without seeing what the camera can see. With any luck this'll be solved by the time you get hold of one. But we advise getting used to the idea you might have to deal with similar kinds of issues.
READ MORE: HTC Desire Eye review
Not running Duracells
One element that's not going to be fixed completely by an update or two is the battery life. As is always the worry with a phone thing enough to slice cheese with, stamina is not great.
The Oppo R5 fits in a 2000mAh battery, even smaller than the unit of a 4.5-inch Moto G 2013. This is a much larger (well at least in terms of screen size) phone, and if you indulge in a bit of web browsing you can drain it in the space of a day without too much trouble.
With a phone of this grade, we like to see a good chunk of battery left over in the morning of the second day. And it's just not there in the Oppo R5. In our looped video test it lasted for eight hours, which isn't diastrous among phones in general, but when rivals such as the Xperia Z3 get into the teens of hours, it's just not really good enough.
It does have a special trick up its sleeve, though. The Oppo R5 has a Rapid Charge adapter that gets you up to 75 per cent charge within half an hour. It uses a 5A plug rather than the 1A/2A one you see bundled with most phones. You may have to charge often, but at least it won't take too long each time.
This is something you don't generally see from the bigger names: Oppo thrives on offering quirky bonus features not seen elsewhere.
READ MORE: Sony Xperia Z3 review
Not all 4G is the same
However, its unusual approach doesn't pay off everywhere. While the Oppo R5 is a 4G phone, it doesn't actaully support every 4G band used in the UK.
Like the OnePlus One, it lacks support for LTE band 20, the 800MHz band, which is used by a whole bunch of networks: O2, Tesco, GiffGaff and Vodafone. If you're on EE of Three and plan to stay there, no problem. It'll be a deal breaker for some, though.
One other compromise you might expect of such a slim phone is speaker quality. Sure enough, the Oppo R5 has a single speaker, but it's front-loaded up where the earpiece is. Front speakers are handy, but this one is a little thin-sounding compared with the best out there - miles off what you get in the (relatively) beefy-sounding HTC One (M8) from its BoomSound speakers.
READ MORE: HTC One M8 review
Oppo R5 Verdict
The Oppo R5 is a phone made with a clear purpose. It wanted to become the thinnest phone in the world. It managed it, everyone clapped, then moved on.
Its issue is that it needs to continue to impress in the days and weeks after you first get it out of the box and go 'ooh' over how slim it is. It doesn't really manage that.
The quirky, buggy software needs a bit more fine-tuning and - primarily - the battery life just doesn't quite give enough insurance for those with busy lives. Fast charge hardware is much appreciated, but it seems a shame it's used as an excuse for the relatively poor core stamina.
In other respects the Oppo R5 is perfectly good, and worthy of its price tag. But would we actually recommend buying it over the wealth of other handset options at this price? Probably not.