Oppo A91 review

Name: OPPO A91
Brand: Oppo

Alex Kidman

Last updated: Apr 28, 2020

Quick verdict: Oppo's latest phone offering shows just how much value you can get out of a mid-range device.

Quad camera set-up gives lots of flexibility
Very fast charging
Still has a headphone jack!

ColorOS is still a bit of a muddle
Low light camera isn't great
Fingerprint sensor isn't always reliable

6.4 inches

Display size

2400 x 1080px

128GB

Internal storage

48MP + 8MP + 2MP

Rear camera

4,025 mAh

Battery size

Finder rated as Good vs similar phones

Details

Display

Display Size

6.4 inches

Resolution

2400 x 1080px

Pixels per inch (PPI)

408 ppi

Camera

Rear camera megapixels

48MP + 8MP + 2MP

Rear camera aperture size

f/1.79 + f/2.25 + f/2.4

Video recording

1080p

Front camera megapixels

16MP

Front camera aperture size

f/2.0

Physical Dimensions

Dimensions

160.2mm x 73.3mm x 7.9mm

Weight

172g

Connectivity

NFC

Wi-Fi

802.11 a/b/g/n/ac

Network category speed

N/A

Power, storage and battery

RAM

4GB / 8GB

Operating system

Android 9

Internal storage

128GB

Battery capacity

4,025mAh

Device features

Headphone jack

Yes

Fingerprint sensor

Yes

Water resistance rating

N/A

Launch price (RRP)	$0

Alex Kidman

Alex Kidman was the tech and telco editor at Finder and is now a freelance technology writer. He's been a technology writer with experience spanning more than 20 years, writing and editing at Gizmodo, CNET, PC Magazine, Kotaku and many more. Alex has a Bachelor of Arts from the University of New England and a serious passion for retro gaming.

Where to buy

We've seen a lot of work in the premium space from Oppo of late with phones like the upcoming Oppo Find X2, but the Chinese firm's primary market has long been in more affordable fare. That's where its latest A series phone, the Oppo A91 resides.

$499 buys you a phone with a large AMOLED display, quad cameras at the back and the promise of Oppo's exceptionally fast charging to boot. While plenty of phones promise a lot in their marketing spiel, the Oppo A91 actually delivers on those promises, delivering a phone with exceptional value in the mid-range market.

Design

Good 6.4-inch display
Choice of two colours
Headphone jack still present
In-display fingerprint reader

The Oppo A91 features a 6.4-inch AMOLED display with a 2,400 x 1,080 pixel resolution, quite sharp for a phone in its price category. Like many Chinese produced phones, the default colour temperature is a little on the garish side, but not to a level that's absolutely distracting. The Oppo A91 uses a teardrop style notch to reduce the impact of its front facing selfie camera, although there's no facility within the settings to "black out" this area if you prefer a top full-screen band to fully obscure it.
Biometric unlocking is handled by facial recognition, although there's no special camera to properly assess this, so it's not terribly secure, or via an in-display fingerprint reader. There's some cool cachet still in having it light up green when you press it, although I did find its strike rate for recognising my enrolled digits wasn't great.
Oppo sells the Oppo A91 in two different shades in Australia, in either "Blazing Blue" or "Lightening Black". That's "Lightening" with an "e", because Oppo wants to accentuate how little the Oppo A91 weighs, presumably. At only 172g it's not exactly bulky, but I've certainly tested lighter phones in my time. The plastic rear of the Lightening Black model as tested was predictably an utter fingerprint magnet within seconds of me switching it on. Oppo does provide a simple clear plastic case to protect the A91 and reduce that fingerprint smudge factor a lot. As always, it's a good idea to drop a case onto any phone, because it's the simplest level of protection you can give it.
Controls are kept simple with a right-hand side power button and left-hand side volume controls. While we've seen some mid-range phones start to play with dropping a 3.5mm headphone jack, that's not an issue for the Oppo A91, which fits one in at the base of the phone for your wired headphone needs.

Camera

Quad camera gives good simple results in most situations
Night mode isn't great

Oppo's big pitch in its value segments has long rested in the prowess of its mobile phone cameras, and the Oppo A91 is no different. From a raw specification level, it certainly sounds like you're getting a lot of camera for your money.
At the back, there's a primary 48MP f/1.79 sensor, alongside an 8MP wide angle f/2.25, 2MP portrait and 2MP f/2.4 mono lens. At the front the offering is a little more basic with just a 16MP front facing sensor; we've seen some competitors go for dual lens either for wide selfies or depth sensing for bokeh, but that's not within the A91's playbook.
That 48MP sensor is the primary selling point, but like so many competitors, by default it doesn't produce 48MP shots unless you explicitly tell it to do so. Instead it uses pixel binning to bump down to 12MP photos with larger effective pixel sites for better clarity and (in theory) better low light performance.
Oppo keeps its own camera app relatively simple, presumably a callback to the era when its ColorOS was a more blatant iOS copy – or homage if you wanted to be kind – but that does mean that while you've got four rear cameras, you're really only going to be "shooting" with two of them at most. Within the camera UI, there's no direct way to access the portrait or mono lenses, which are instead used in specific modes to improve shots via Oppo's own inbuilt AI engine.
Oppo also uses its hybrid lenses and that primary 48MP sensor to give the Oppo A91 telephoto shooting capabilities, which are fixed at 1x, 2x and 5x, although you can further push that out to 10x digital if you're particularly keen.
We've seen some impressive zoom capabilities in the top end of premium phone photography lately, and while the Oppo A91 doesn't challenge phones like the Samsung Galaxy S20 Ultra or Huawei P40 Pro, for a $499 phone it's fairly good. To test this out I went on my daily constitutional walk to a nearby park. The coronavirus shutdown meant I wasn't allowed in the park, but with a zoom lens I could shoot a slide to show off what the A91 is capable of.
Here's a wide shot of the park (or as Oppo's camera app would have it, 1x).
The same shot at 2x still shows pleasing levels of detail.
Crunch into 5x and you're predictably losing detail fast.
10x would be acceptable for observing detail if you must, but you wouldn't want to use it anywhere serious.
The pixel binning capability of the Oppo A91 should also allow a lot more light into your photos, which should then correlate to decent low light performance. The obvious competitor phone here is Google's exceptional Pixel 3a (and presumably the Pixel 4a once it breaks cover), but here the Oppo A91 did struggle, delivering shots with lots of noise and poor colour representation relative to Google's performance. Compared to other mid-range phones it's about what you'd expect, which is to say not much.
Oppo A91 sample photos

Performance

Snapdragon 665 is as mid-range as it gets
Older Android version
Nicely durable

In the mid-range phone market there's a lot of jostling between the higher end of MediaTek's budget processors and the lower end of Qualcomm's Snapdragon range. For the Oppo A91, the Chinese maker has gone down the MediaTek route, with a Mediatek MT6771V Helio P70 paired up with 8GB of RAM and 128GB of onboard storage.
In benchmark terms, it allows the A91 to sit near the top of the pack using Geekbench 5's CPU test, although it's pipped by fellow BBK Electronics stablemate realme ever so slightly:
But it's a different story in graphics performance, where the A91's Mali-G72 GPU sits more in the middle of the pack:
In day to day usage, the Oppo A91 runs pretty much exactly like I'd expect a mid-range 2020 Android phone to operate. It's absolutely fine for everyday browsing, email and social media, but if you want to run higher end applications or take advantage of split screen multi-tasking you'll hit its performance wall pretty soon.
Like every other Oppo phone, the Oppo A91 runs on Android; in its case it's Android 9 highly modified via Oppo's own ColorOS 6. Android 10 would have been preferable, especially as mid-range Android phones often have poor track records when it comes to actual updates. ColorOS started life as a very blatant homage to Apple's iOS, which did make it a good choice for those switching from Apple's platform, but over the years it's moved into more of a middle ground between iOS and stock Android.
The issue there is that it can sometimes be confusing working out where a control might be, or how ColorOS might think about onscreen elements relative to the way that either "pure" approach does. It's nothing you can't largely sort out with a little time, and being Android it's also mostly configurable the way you like it. It can be a little stressful launching Oppo's own applications to be hit with a bunch of security requests the first time out. I'm still not sure why a default photo gallery app might want to know my phone number and call logs, and I'm not entirely comfortable using it as a result, but your comfort level may differ.
The model of the Oppo A91 sold in Australia and supplied for review does feature NFC, so it should be fully Google Pay compatible. Although as always, it's well worth checking that this is the model you get if you're buying one online; not every international model might have NFC enabled, and it's not mentioned on Oppo's local website either.

Battery life

4,025mAh battery gives decent battery life
Very fast VOOC charging

We've seen a lot of mid-range phones start to tick up their battery capacities, and the Oppo A91 is no exception, with a stated full battery capacity of 4,025mAh. It supports Oppo's own in-house VOOC fast charging via USB C, but you'll have to remember to pack the VOOC charger if you want its ultra-rapid charging everywhere you go. Other chargers will of course work just fine, but nowhere near as quickly. As with most rapid chargers, the trade-off for a quickly charging device is one that's ever so slightly warm when it's done.
To put the Oppo A91 through its paces, I ran it through our standard battery test, streaming a full-screen YouTube video at maximum brightness and moderate volume for an hour to get a comparative picture of battery life. There's a little wriggle room here, because the current coronavirus pandemic has seen YouTube drop video quality down to a maximum 480p globally where I'd usually test at 1,080p, so these aren't quite like-for-like comparisons. Here's how the Oppo A91's 4,025mAh battery compared after an hour's testing:
Phones that fall in the above 90% bracket are typically good for at least a day's usage, and that's certainly true for the Oppo A91, which anecdotally lasted nicely into a second day's usage through most of my testing period. It's not quite up there with the very best you can get in any phone, but for the mid-range it compares well. Oppo's own VOOC charging makes it simple to top it up when and if it does run low, too.

Verdict

A great all-round phone

Should you buy it?

Mid-range phones are absolutely where you should be looking for your next phone purchase in most circumstances; we've certainly reached the point where they're "good enough" for everyday use, and it's only in the higher end camera feature set that premium phones truly stand out.

The Oppo A91 is an excellent example of this phenomenon. You're not quite getting every feature you might want – there's no water resistance, no wireless charging and its low light camera performance isn't quite up there either – but as a complete package it's otherwise excellent.

Pricing and availability

Price

RRP $499

Where to buy

Bing Lee

Catch

Alternatives

In the mid-range, if you wanted a cleaner Android experience and better low light photography, Google's Pixel 3a remains our pick of the bunch, although that may soon be supplanted by the long-rumoured Pixel 4a.

Oppo's stablemate realme also offers very good camera-centric phones in the mid-range space with models such as the realme XT and freshly launched realme 6 to consider.

If you're more on the iOS side of the fence, the Apple iPhone SE 2020 is freshly available, although its cheapest model at $749 is quite a bit more expensive than the Oppo A91.