Back in March, at Mobile World Congress 2015, Microsoft unveiled two new additions to its range of Windows Phones: the Lumia 640 and its larger sibling, the Lumia 640 XL. Many people – including some of us at Neowin – rolled their eyes at the arrival of yet more lower-end devices; after all, including these two handsets, the company has now launched seven affordable smartphones (Lumias 430 Dual SIM, 435, 532, 535, 540, 640 and 640 XL) in the last six months!
Over the last few weeks, I’ve been testing both the Lumia 640 and 640 XL, and earlier this month, we published our review of the larger device. This time, it’s the turn of the smaller Lumia 640 – and while you may be tempted to dismiss it as just another cheap Windows Phone, to do so would be to overlook a very capable handset that has a lot to offer, especially given its low price.
But as I discovered while testing the Lumia 640, it’s not entirely without its flaws.
Lumia 640 vs 640 XL
There are numerous overlaps on the respective spec sheets of the 640 and its bigger brother, but there are some key differences as well, including:
- 5-inch display (vs 5.7-inch display on the 640 XL)
- 8MP rear camera (vs 13MP with ZEISS optics)
- 0.9MP front-facing camera (vs 5MP)
- 2500mAh battery (vs 3000mAh)
But given the many similarities between the two handsets, you may also spot some similarities with our earlier review of the Lumia 640 XL – particularly the OS+Software section, which is reproduced here more or less verbatim.
Like the XL, the smaller Lumia 640 is available in several variants – with/without 4G LTE connectivity; and with/without dual-SIM support. For this review, Microsoft UK provided us with the single-SIM 4G LTE model, which is now on sale in the United Kingdom and various other markets around the world.
Specs + design
Let’s kick things off with a closer look at the Lumia 640’s key specs:
|Microsoft Lumia 640 LTE|
|Dimensions||141.3 x 72.2 x 8.8mm
|Connectivity||GSM: 850 / 900 / 1800 / 1900
HDSPA: 850 / 900 / 2100
4G LTE: Band 1 (2100); Band 3 (1800); Band 7 (2600); Band 8 (900); Band 20 (800)
Wi-Fi: 802.11 b/g/n
Bluetooth 4.0 LE with A2DP
A-GPS / A-GLONASS
Screen sharing (Miracast-enabled)
3.5mm audio jack
|Display||5-inch IPS LCD capacitive multitouch
294ppi pixel density
Corning Gorilla Glass 3
|Processor||Qualcomm Snapdragon 400 SoC
Quad-core 1.2GHz Cortex-A7 CPU
|Graphics||Adreno 305 GPU|
Ambient light sensor
|Storage options||8GB onboard storage
microSD card slot (up to 128GB)
- 8-megapixel backside-illuminated sensor
- LED flash
- 1080p video recording at 30fps
- 0.9-megapixel sensor
- Wide angle lens
- 720p video recording at 30fps
|Battery||2500mAh Li-ion battery
|Operating system||Windows Phone 8.1 Update 2
Microsoft Lumia Denim firmware
|Price + availability||MSRP: from €159 EUR exc. taxes/subsidies (4G LTE model)
On sale in the US: $129 off-contract with Cricket Wireless
Available in various other markets now; see local pricing
As with the XL, Microsoft has packed some pretty decent specs into the Lumia 640, including some features that you might not expect on a lower-end device.
While the XL replaced the much older Lumia 1320, the Lumia 640 effectively succeeds the Lumia 630 and 635, which were announced just over a year ago, and which remain on sale in many markets. On paper, at least, the 640 offers a much more compelling package than the 630/635.
Aside from the larger high-def display, the 640 also gets a front-facing camera – a feature that Nokia, in a foolish cost-cutting measure, excluded from the 630/635. Those devices also had to make do without an ambient light sensor – another example of penny-pinching resulting in a poor user experience, as we'll go into later.
The 640 gets an impressive array of sensors; in addition to the light sensor, you’ll also get an accelerometer, proximity sensor, magnetometer, and SensorCore – a technology developed in partnership with Qualcomm, which is designed for tracking motion data (such as steps walked and distance travelled) without the need for additional hardware.
The Lumia 640 also gets some nice features like integrated NFC (for mobile payments and rapid wireless device pairing), 1080p video recording, HDR (high dynamic range) image capture capabilities, and Miracast wireless screen sharing.
But one disappointment worth highlighting on the spec sheet is the processor. Like the XL, the Lumia 640 has a quad-core 1.2GHz Snapdragon 400 processor – that’s the same as the year-old Lumia 630/635. On the XL, this was almost forgivable, despite its higher price, as it represented a significant leap forward over the older dual-core Snapdragon S4 that featured in the Lumia 1320 that it replaced.
But given that other handsets – including Windows Phones like the new LG Lancet – are now being launched with the newer and more power-efficient Snapdragon 410, it’s disappointing that the Lumia 640 hasn’t made the same jump, and is stuck with the same chip as its predecessor.
But spec sheets are only an indicator of a handset’s capabilities – you can’t judge a book by its cover, and you certainly can’t judge a phone solely by what it offers on paper. Before we get into how the Lumia 640 performs in the real world, let’s take a quick look around the device.
As you’ve probably noticed, the 640 doesn’t exactly push the boat out when it comes to design – indeed, it looks an awful lot like many other Lumia devices. That’s not a bad thing in and of itself – personally, I think it’s rather nice to look at – but even Microsoft executives must be tired of trying to keep a straight face while talking about how bold and exciting Lumia design is, when we’ve seen the same basic formula applied to its handsets so many times before.
The front of the device is in the familiar Lumia style: a sheet of Gorilla Glass 3 ringed with a ‘halo’ of color from the rear cover. While the Microsoft logo is located at the top-center, below the speaker grille, the front-facing camera is curiously offset, positioned at the top-left corner.
The microphone cut-out at the bottom is also off-center, but there are no hardware buttons on the front of the device – the Back, Start and Search buttons are located on the display instead, and can be swiped on- and off-screen as desired.
As on other Lumia handsets, the left edge of the device is completely featureless, while the top of the device is home to the 3.5mm headphone jack.
A microUSB 2.0 port can be found at the bottom, while the right edge houses the only physical buttons on the device: the power/wake button, positioned dead-center between top and bottom; and the up/down volume controls. Sadly, the Lumia 640 is yet another low-end device on which Microsoft hasn’t bothered to include a dedicated hardware camera button, despite the huge improvements to the user experience that this provides on its more expensive handsets. Eugh.
The rear of the device is made up entirely of the removable rear cover, on which Microsoft has added a second logo, along with cut-outs for the rear speaker (positioned at the lower left of the image above), the 8-megapixel camera, and the LED flash.
Unlike the Lumia 640 XL, which features a 13-megapixel camera with ZEISS optics, the 640’s more basic camera architecture is evidently less bulky, and doesn’t extrude from the main body of the device in the same way as its larger sibling.
However, while there isn’t a noticeable ‘hump’ on the 640, the camera module isn’t quite flush with the rear cover, and the hard-edged ring around the lens cover has an annoying tendency to pick up dust and pocket lint that must occasionally be wiped off before taking a photo.
The handset that Microsoft provided came with a glossy cyan cover, and personally, I’m not a fan. It’s not the color – I’ve been a big fan of cyan Lumias ever since buying the original 800 back in 2011, and I think the 640 looks pretty sharp. But as far as I’m concerned, the glossy plastic feels cheap and nasty. It’s also a fingerprint magnet, and on a warm day, it doesn’t take long for the phone to end up looking pretty mucky.
If you’re not keen on the glossy finish either, you can also get the device with a matte finish (or purchase interchangeable glossy or matte covers separately) – and having used a matte cover on the Lumia 640 XL, I think it makes a huge difference to the perception of quality. But whichever side of this debate you’re on, Microsoft offers options to suit your tastes.
It can be a bit tricky at first to remove the rear cover, but once you know what you’re doing, it’s not such a hassle, and the chances are you won’t have to do this too often anyway.
You’ll need to remove the 2500mAh battery to access the microSIM card slot (note the slot where the second SIM would go is plugged up on this model) and the microSD card slot, which supports cards up to 128GB.
Like the XL, the Lumia 640 feels rock solid in its construction – no flex and no creaks of any kind – and given the low price point of the device, that’s a big bonus for buyers on a budget.
But again, just as with the XL, I wish the design of the Lumia 640 was a bit more interesting. Having seen this basic design recycled ad nauseam for Lumia handsets, I’m sure I’m not the only one ready for Microsoft to mix things up a bit.
While the Lumia 640 XL has a massive 5.7-inch display, the 640 gets a smaller 5-inch screen. Both devices have IPS LCD panels, and both have HD (1280x720px) resolution – and that gives the Lumia 640 a notable advantage over its bigger brother.
The 640’s smaller size with the same resolution provides higher pixel density – 294 pixels per inch, versus the XL’s 258ppi – so everything appears even sharper than it does on the XL’s screen. It obviously can’t match the crystal clarity of a similarly sized display with Full HD (1920x1080px) or Quad HD (2560x1440px) resolution, but the level of detail visible is still impressive, especially in the Lumia 640’s price range. You have to stare pretty closely at the screen to spot individual pixels or anti-aliasing effects around text, and most users should find the quality to be acceptable, if not excellent.
As on the XL, Microsoft has done a good job of calibrating color saturation, providing a sensible balance between rich and vivid colors without descending into exaggerated or over-saturated hues. That said, the default color settings do have a very slight yellow tint – most noticeable on full white backgrounds – but Microsoft has provided an easy-to-use color management tool, built into the OS, to allow users to calibrate the display’s settings to their individual tastes.
Aside from this, the Lumia 640’s display is really very impressive at this price point, with good color fidelity, excellent contrasts and – thanks to the ClearBlack technology that Microsoft acquired from Nokia – very deep blacks, especially for an LCD panel.
Viewing angles are also superb on the Lumia 640’s screen. There’s virtually no color distortion at all even when viewing at the most extreme angles – having witnessed some truly wild color variations on low-end handsets with cheap and nasty LCD screens, like the Acer Liquid M220, it’s good to see that Microsoft hasn’t cut corners here.
The Lumia 640’s predecessors, the near-identical Lumia 630 and 635, were victims of some absurd cost-cutting measures by Nokia. Despite Nokia including a selfie cam and ambient light sensor on some of its cheaper – and truly awful – Nokia X-series Android handsets, the more expensive 630/635 had to make do without these features, forcing painful compromises upon buyers of these devices.
Thankfully, Microsoft has seen sense here. While its predecessors required users to manually control screen brightness – which meant, for example, that whenever you went outside into sunlight, you had to open the settings to increase the brightness in order to be able to see your screen – the Lumia 640’s ambient light sensor can do this job for you.
And it does the job pretty well, as far as I’m concerned. In fact – with the exception of adjusting brightness levels to take photos of the device for this review – I don’t recall a single occasion on which I had to manually adjust the screen brightness for myself. The sensor always correctly identified when I was in bed with all the lights off and browsing the web, taking it down to its very lowest level to allow me to read in comfort; or when I was outdoors in intense sunlight, pushing the brightness up to the highest level to increase visibility.
As with many Lumia handsets, Microsoft uses algorithms to help improve visibility of the 640’s screen, combining this software approach with the impressive brightness of the display’s backlight to boost outdoor visibility. The 640 coped admirably with all but the most intense direct sunlight – but inevitably, with a highly reflective glass panel on the front of the device, there’s only so much that can be done to improve visibility outdoors.
As on the 640 XL, Microsoft has added a feature to the Lumia 640 that first appeared on Nokia’s Lumia flagships: Glance Screen. This ultra-low-power feature shows time and basic notifications on the display even when the screen is effectively turned off, and you can customize the settings to minimize power consumption even further, or simply deactivate it completely, if you prefer.
The display also supports double-tap-to-wake, so if the phone is lying on your desk or your bedside table, you can simply double-tap the screen to power it up, instead of fumbling around to find the power button.
I personally found the 5.7-inch Lumia 640 XL to be just a bit too big to handle some of the time – typing or reaching for buttons on its giant display with one hand often proved especially challenging. But at 5-inches, the Lumia 640 hits the sweet-spot between having a large and beautiful display, and being able to comfortably use it one-handed.
I know that some people scoff about such considerations, but if you’ve ever had to reach for your phone to reply to an email while carrying your shopping, or while walking down the road and holding your kid’s hand or whatever, I’m sure you’ll appreciate the value of being able to comfortably use your phone with one hand.
On those occasions when you’ve got two hands free, using the Lumia 640 is an absolute pleasure. Microsoft’s Windows Phone keyboard is still one of the best available on any mobile device, and tapping at the keys with two thumbs is a quick and painless experience.
However, I do think that the Lumia 640 is perhaps just a bit bigger than it really should be – it’s both wider and taller than the Lumia 930 (sold in the US as the Lumia Icon), which has the same-sized display, and this is simply because the 640’s bezels are so chunky, and the rear cover only adds to the overall width of the device.
That’s more of a passing observation than an angry criticism though – but it’s still worth noting that if Microsoft had managed to shave a few millimeters off the handset’s width, it would have made the one-handed usage experience even better, particularly for those with smaller hands.
OS + software
The Lumia 640 and 640 XL were the first two handsets to launch with Windows Phone 8.1 Update 2 pre-installed. There’s not a great deal to get excited about in this latest version, but there are a couple of welcome features.
There’s a redesigned Settings hub, more logically organized into various sections that you can ‘jump’ to by tapping any of the headings, as well as a new search function. If you’re familiar with Windows Phone, you’ll know that this is a great improvement over the utterly horrible long list of settings in no particular order that the OS has had to suffer with for years. For the first time, you can also pin individual settings to the Start screen – and if you’re wondering why it’s taken Microsoft this long to make that happen, you’re not the only one.
Another welcome addition is that of native MKV video playback support, which lets you watch these files on the handset via the pre-installed Xbox Video app without needing to download any additional software or codecs.
Update 2 also introduces new remote ‘kill switch’ functionality, in compliance with new US legislation intended to provide a disincentive for mobile device theft.
But besides these additions, the OS will otherwise be very familiar to anyone who has used Windows Phone 8.1 before. If you weren’t a fan before, Update 2 won’t do anything to win you over, but if you have a soft spot – or a hard spot, perhaps, depending on the level of your passion – for the OS, you’ll probably appreciate these latest improvements.
In certain markets, of course, that means you’ll get features like Cortana, Microsoft’s brilliant digital ‘personal assistant’, but even where that feature isn’t available, the OS still has a great deal to offer. With Windows 10 for phones coming in the next few months, it seems a little pointless to spend too much time discussing the OS in great detail, especially given that we’ve covered it extensively in earlier reviews.
But it’s worth mentioning that if you buy the Lumia 640, you’ll still have to be ready to deal with the app situation on Windows Phone – and you should think very carefully before jumping in if you’re a first-timer to the platform.
Yes, many of the top apps are here – including the likes of Facebook, Twitter, Pinterest, Spotify, eBay, WhatsApp, Vine, Viber, LINE, Evernote, Dropbox and many, many more. But a presence on the platform is no guarantee of high quality – the BBC iPlayer app in the UK, for example, is little more than a weak web wrapper, which lacks many, if not most, of the rich multimedia features available in the same app on other platforms. The Instagram app hasn’t been updated in over a year and, yep, also lacks features available on rival operating systems. This is a common story when it comes to Windows Phone apps.
When it comes to some of the less heavily-downloaded apps – those that aren't really 'top tier', but which smaller groups of people consider important or useful; like your bank, your local cinema, your preferred airline, etc – there’s a good chance they won’t be in the Windows Phone Store at all. With global market share for the platform still at less than 5%, there’s little incentive for brands and developers to offer and support apps on Windows Phone for now.
This situation should improve with major new plans to make it easier for developers to bring their iOS and Android apps to Windows 10 for phones, but it will take time for the effects of this to kick in, so be sure to adjust your expectations accordingly.
Still, it’s worth highlighting some of the excellent software that Microsoft pre-installs on the Lumia 640, ready to use out of the box. Its suite of MSN apps – including News, Sport, Weather, Money, Food & Drink and others – is brilliant, and while they’re not unique to Windows Phone any longer (MS has also ported them to other operating systems), they remain top-notch examples of well-designed and highly functional apps on the platform.
Microsoft also inherited many apps from Nokia, some of which are pre-installed on the device, while others can be found in the Store under the ‘Lumia collection’. Some of these are fun tools, like the Lumia Selfie app, which lets you quickly edit and add filters to make your selfies look that little bit more fabulous. There are also great camera tools like Lumia Refocus, which allows you to take a pic and then shift the focus of the image later.
There's one last bit of software worth mentioning, although it's not actually intended for your phone at all. The Lumia 640 and 640 XL are the first two handsets to come with a free one-year Office 365 Personal subscription for your PC. Worth around $70 in the US and £60 in the UK, this adds a huge amount of value to the handset, and can be easily redeemed via the ‘Office 365 Gift’ app, that can be found by navigating to the Lumia collection in the Windows Phone Store on the device itself.
Performance + media
Unlike many of the low-cost Windows Phones that have popped up in recent months – and not just from Microsoft – the Lumia 640 doesn’t feature the entry-level Snapdragon 200 processor, but the next one up in Qualcomm’s line-up: a quad-core 1.2GHz Snapdragon 400.
This is the same processor used in the larger and more expensive Lumia 640 XL – but it’s also the same chip used in the 640’s predecessors, the Lumia 630 and 635, and frankly, it’s hard to not be disappointed by this choice. Qualcomm has since launched the Snapdragon 410 processor, and other manufacturers are already launching handsets with this new chip, including Windows Phones, such as the LG Lancet and the BLU Win HD LTE.
Still, I was pretty impressed with the performance of the Snapdragon 400 when I reviewed the Lumia 630 last year – but is it similarly capable on the new Lumia 640? The short answer is: yes.
In fact, paired with a full 1GB of RAM on the 640 (compared with just 512MB on the 630), the Snapdragon 400 delivered some pretty solid performance for everything I threw at it during the weeks that I was testing it.
I've never been a fan of performance benchmark tools - especially given the fact that comparisons with other devices can be easily rendered meaningless by firms that manipulate benchmarks to make their handsets appear better. As in other reviews that I've written for Neowin, my report on the handset's performance is therefore based upon my own real-world experience, rather than on benchmarking analysis.
Microsoft has worked extensively to optimize Windows Phone to work well even with the most modest specs, and having tested the same chip running on the Lumia 630 and, more recently, on the 640 XL, it came as no surprise that the OS ran more or less flawlessly on the 640 as well.
That’s not to say that you won’t see faster performance on higher-end Windows Phones with newer and more powerful chips – you certainly will – but most buyers in this price range will probably be delighted with how smoothly everything runs on the 640, especially compared with how some low-end hardware tends to run Android.
However, those who obsess over the minutiae of OS operations, and who concern themselves with spotting the smallest flaws in everything – and with a mixture of pride and shame, I count myself among them – might spot a near-imperceptible and very occasional amount of stutter in some animations throughout the OS.
Every now and then, a transition animation appears to skip a couple of frames, or a Live Tile might jump ever so slightly while flipping over to reveal its reverse side. I made the same observations about the 640 XL - but really, this is the kind of stuff that you’re only likely to spot if you’re looking for it, and I don’t imagine for a moment that it would trouble any ‘average’ buyer.
But I didn’t spot any dropped frames or stuttering performance when playing even a graphics-intensive game like Asphalt 8: Airborne on the Lumia 640. Just as on the XL, the 640 ran the game very well indeed, but it took a while to load, and of course, this is one area where higher-end devices with faster application and graphics processors make a difference.
And again, just like on the XL, I found that the 8GB of integrated storage on the Lumia 640 simply wasn’t enough to comfortably accommodate all the various media that I needed on the device, without having to resort to uninstalling games and apps to make way for new ones. That said, given the lower price of the 640, I can certainly forgive its limited storage more readily than on the more costly 640 XL – but I live in hope that 16GB will soon become the new norm for even low-end devices.
If you install a fair few apps, enjoy playing games, store your music on the device, and regularly take lots of photos, there’s simply no way that you’ll be able to get by with just the 8GB of storage that it comes with. Even if you’re not a big gamer, limit your apps and stream your music, the chances are it won’t take long before you reach the limits of the device’s storage capacity.
Thankfully, the Lumia 640 has a microSD slot that can handle cards up to 128GB. The largest cards will obviously set you back quite a bit of money, but smaller capacities can be purchased inexpensively, and I’m pretty sure that most buyers won’t regret spending a few bucks to ensure that they don’t have to worry about storage issues from day to day.
Performance in loading and running other apps, besides games, was generally excellent – indeed, in going back through my review notes over the weeks that I tested the device, I couldn’t find any observations to criticize its performance in this respect. Multi-tasking performance was pretty good too – one of the earliest notes that I made on this subject simply reads: “Multi-tasking: bloody quick!” and while that might be overstating things a bit, I don’t recall any occasions on which my user experience was unacceptably delayed by a long wait to switch from one active app to another.
To put it simply, the phone handled every task that I demanded of it capably and quickly. Yes, there are faster phones out there, but at this price range, I can’t fault the Lumia 640’s performance at all. Between its beautiful display and impressive performance, I’m quite sure that most buyers will be pretty pleased with owning and using it.
But of course, let’s not forget that underneath all the bells and whistles that the device has to offer, it’s still a phone as well – and on that front, the 640 also did a good job. The ear speaker provided good audio quality on calls, and the external speaker was loud and clear for hands-free conversations.
When invited to comment on the quality at the other end of the line – i.e. how well people could hear me – many friends and family that I asked remarked that my voice actually sounded clearer than normal in calls, compared with when I usually speak with them on my Lumia 930 or LG G3. Bear in mind, however, that the 640 doesn’t come with a headset in the box, so you’ll need to supply your own.
When out and about, I used the Lumia 640 on the UK’s largest network, EE, using both 3G and 4G SIM cards, in and around London. I found that the device did a great job of both attaining and retaining signal, although there were two notable anomalies in my testing.
On one occasion, I was in central London, close to the London Eye observation wheel, just across the River Thames from the Houses of Parliament - exactly the kind of place where you'd probably expect rock-solid signal. While my Lumia 930 had no trouble grabbing four bars of 4G LTE signal, the Lumia 640 stubbornly refused to get more than two bars at EDGE speeds, despite being on the same network, and both handsets having 4G SIM cards on the same network. I had to wait until I was in a taxi around 100 meters down the road before the 640 suddenly kicked up to HSPA+ and then 4G LTE, and I was finally able to send a tweet from the device.
Conversely, I was very pleasantly surprised by another cellular anomaly that had occurred a couple of weeks earlier. There’s a stretch of track on my local railway line which seems to be a bit of a dead zone for mobile signal – and it’s something of an in-joke for regular travellers on most mobile networks who pass through that section of the line, hearing a wave of sighs rippling through the train, as many passengers find their calls dropped, and web pages suddenly failing to load.
And yet, on this one occasion, while in the middle of a call and expecting it to drop as it normally would, the Lumia 640 managed to keep the call going, albeit with a massive reduction in audio quality, and some difficulty between my friend and I being able to hear each other on the call for a few seconds. A quick glance at the display showed that just one bar of EDGE signal was indicated – but it was enough to get me through the dead zone, and through the call.
Predictably, when I tried the same thing a week later, the Lumia 640 dropped the call faster than a flaming bag of dog poo – so it’s not quite the miracle worker that it first seemed.
Can’t win ‘em all.
With its latest devices, there’s a sense that Microsoft understands the importance of battery life as part of the overall experience of owning and using a device. The mid-range Lumia 640 XL, for example, has a large 3000mAh battery – the same size as LG’s new (and more powerful) G4 Android flagship.
The Lumia 640 has a smaller 2500mAh battery – not surprising, given its smaller display – but that’s still fairly impressive. To put that into context, the similarly sized Lumia 930 flagship only has a 2420mAh battery – and given how often I end up bitching and moaning about my 930 running out of juice before the end of the day, it’s even more remarkable to me that the much more affordable and less power-hungry Lumia 640 has a battery with even more capacity.
And as a result… well, there’s no other way to put this: the Lumia 640’s battery life is simply superb.
When I’m out and about, a typical day of smartphone usage for me will include:
- 30-60 minutes of voice calls
- 30-60 minutes of casual games (Wordament, Solitaire, Trivia Crack, etc)
- Reading/writing emails throughout the day
- Social media (mainly Facebook/Twitter)
- Occasional IM via Skype
- Occasional web browsing
- Taking a few random photos
- 60 minutes of music streaming (via Xbox Music, MixRadio, Spotify)
- Connecting to Wi-Fi via available hotspots
Like most users, I often dip into other apps, such as those for shopping and banking, along with the odd bit of video streaming via apps like YouTube and TVCatchup. Broadly speaking, I think it’s fair to say that all of this isn’t too far removed from how a large proportion of handset owners use their devices.
With this type of usage, my Lumia 930 is often running on nothing but its own fumes by around 10pm, if I haven’t managed to find somewhere to give it a quick charge before the end of the day. But the Lumia 640 just kept on going, long after the 930 would have choked and died.
At the end of most days on which I was using the Lumia 640, the battery still had between 30% and 40% remaining. Without consciously managing my usage to extend battery life, I was able to go for two full days without charging, although only on days when I unintentionally spent less time on video streaming and gameplay.
With a much heavier focus on gaming and videos, on a day when I also drafted a few long emails and listened to a lot of music on several train and taxi journeys while darting across town, remaining battery life had fallen to 15% by the time I returned home just after midnight.
Your experience of battery life on the Lumia 640 will differ – perhaps considerably – from my own, depending on exactly how use the features, apps and services on the device. And as on any handset, you’ll also find that taking lots of photos will drain the battery more quickly.
But what I found most remarkable about using the Lumia 640 was the fact that I could take full advantage of its capabilities, doing everything that I wanted to do on it – from watching videos and streaming music, to chatting on Skype, browsing the web, reading and writing emails, and posting inane observations and comments on social media – without once having to worry about battery life during the day.
I can’t overstate what an absolutely joy that was, and what a huge difference that made to using the Lumia 640 from day to day. And I can’t praise Microsoft highly enough for making that possible on a handset that costs a fraction of the price tag of most flagships.
And of course, even if you’re the kind of person who absolutely spanks their battery throughout the day – with a constant audio soundtrack streaming from Spotify, playing graphics-intensive games for hours at a time, taking photos of every cat you see in the street and uploading every pic you take to Facebook – the Lumia 640 has a removable battery, so you can inexpensively buy another one to swap out if you do run out of juice before the day’s end.
While the Lumia 635 had to make do with a 5-megapixel camera, its successor gets a very welcome upgrade with an 8-megapixel sensor - although, unlike the 640 XL, the Lumia 640 doesn't get high-end ZEISS camera optics.
The 640's camera also lacks the sophisticated PureView architecture that's reserved for premium Lumia handsets, and has to make do without useful features like optical image stablization - but it does have a backside-illuminated sensor, dynamic flash, and rich capture capabilities.
As you would expect from a low-cost handset, the Lumia 640's camera isn't going to challenge a DSLR for imaging supremacy, and it's not without its flaws, but it's certainly better than you might expect of a device in its price range.
Take the image above, for example - the level of detail is excellent, with rich and vibrant colors, and good contrasts.
The amount of detail captured by the 640's 8-megapixel sensor is appreciable even in less complex images, like this one - it managed to snap all of the thin support cables across the London Eye observation wheel without any of them getting fuzzily lost into the pale blue background of the sky, which you might see on a lower-resolution camera. There is a very, very slight pinkish tone at the upper right of the image, though, from sunlight hitting the lens at an awkward angle.
You can compensate for the amount of sunlight - or any light - entering the camera's sensor, with the easy-to-use controls baked into the Lumia Camera application on the device. Each of the circular controls in the app adjusts imaging settings such as white balance, ISO levels and exposure time, and by swiping down the control on the far right of the image above, you can reduce the amount of light hitting the lens, with a live preview showing the effect of any adjustments that you make before you've even taken the photo.
That means you can take a picture like the one above. It may look like there's been a terrible explosion in one of the London Eye's capsules, but that's just a burst of sunlight behind the wheel. However, the obvious effect of reducing light levels is that you'll also lose some of the richness of color in the scene, which is why the blue sky in this image appears much darker than it did in the photo of the Eye further up. Objects in the foreground also appear much darker and less detailed for the same reason.
But even with the brightness setting reduced, you can still capture some nice images, like the one above, facing directly into a sunrise over southwest London. It won't win any photography awards, but for a quick point-and-shoot with the camera on a low-cost smartphone, it's hard to fault it.
In lower-light conditions, the Lumia 640 is still capable of snapping some decent pics. Here, at dusk, there wasn't a great deal of light around, yet the camera managed to capture an impressive amount of foreground detail (albeit somewhat lacking in color), but it did a great job of picking up the range of color across the sky as the sun set.
Again, you can turn the brightness settings up to suit your tastes or requirements. In this image, the camera was able to capture more detail and color in the foreground, but the brightest part of the sky, closest to the sun, became too bright, killing the subtle gradient of color in the original scene.
And in much lower lighting conditions, the Lumia 640's camera - unsurprisingly - starts to struggle. With the last of the sun disappearing over the horizon, and night almost falling, the camera's ability to pick up any kind of detail declines considerably, and images become much more grainy.
Frankly, from the camera on a phone in this price range, I'm surprised the low-light results were this good - I was expecting much, much worse. Yes, it has an 8-megapixel sensor, but megapixel counts alone are a fairly meaningless indicator of camera quality. But that's not to say that megapixels don't matter.
More megapixels mean more detail in a photo - assuming the optics are good enough to capture that detail in the first place. The Lumia 640 is certainly capable of grabbing plenty of detail in a scene, like in the image above. Look very closely, and you may spot a creature looking very shifty, like it was plotting something, right in the middle of the photo.
Not wanting to get my feet wet, I couldn't get any closer to the winged beast - and given the size of its beak, that was probably for the best. But with half a mind on wanting to save a photo of the bird showing it more clearly for this review - and the other half wondering what it might taste like with some French mustard - I opened the Lumia Creative Studio app, quickly zooming and cropping the image in just a few seconds.
The result is the image above - and if you read my review of the Lumia 640 XL, you may well have noticed that the results aren't quite as successful here, and much of that is down to the lower megapixel count. To put it simply, I zoomed in to a level where there just wasn't enough detail available to successfully crop the image without losing definition.
As a result, you can see that there's some graining and patchiness in the overall quality of the cropped photo - but had I not zoomed in quite so far, I might have got away with a more successful image.
Helpfully, though, Lumia Creative Studio lets you keep the original and save your edits as copies, so even if you don't get the result you're after the first time around, you can go back to the original and try again until you're satisfied.
Alas, the camera experience was slightly tainted by Microsoft's decision to exclude a dedicated hardware button from the device. On its more expensive handsets, you can simply whip your phone out of your pocket or bag, hold the camera button down (even while the device is locked), and quickly take a photo by pressing the button again.
On the Lumia 640, you have to first switch it on, then swipe down the Action Center from the top of the screen, then tap the camera button, and once it's loaded, you can then start taking pics with the on-screen controls. This is pretty poor compared with the much nicer (and speedier) experience on higher-end devices, and it means you're more likely to lose those moments when you want to quickly capture a scene, while you're fiddling about with on-screen buttons.
But while the Lumia 640's camera obviously can't compete with the flagships of the smartphone world, it's hard to fault its abilities at this price level. Yes, it struggles in low-light, but frankly, you'll have to pay more for your hardware if you're expecting a phone to capture flawless photos in all conditions.
And if you take a bit of time to acquaint yourself with the easy-to-use Lumia Camera app controls, to adjust settings like brightness, depth of field, white balance and the like, you should find that you're able to take photos with the Lumia 640 that you'll be very happy with.
Conclusion + verdict
Given how many low-cost handsets Microsoft has introduced in recent months, it would very easy to overlook this one as just another cheap Windows Phone. But do so, and you’ll be missing out on a very capable device. Indeed, all things considered – including the all-important price factor – this is one of the most impressive Windows Phones ever released.
Compare the Lumia 640 to a flagship and you’ll obviously be disappointed – but you’ll also be missing the point completely. It isn’t designed to compete with range-topping smartphones that cost four or five times more – it’s designed for users who don’t care about, or who simply can’t afford, the features that a top-of-the-line handset offers.
And for these users, the Lumia 640 is an excellent choice. It has a big and beautiful high-def display, it can handle pretty much everything that most people will ask of it with solid and consistent performance, and it has a fairly good camera – although inevitably, it does have its limitations, particularly in low-light conditions.
That said, I continue to be frustrated by the bizarre choice of excluding a dedicated hardware button for the camera on lower-end Lumia devices. I haven’t yet heard any reasonable explanation from Microsoft about why this button is exclusively reserved for higher-end handsets, so I can only assume that this is the result of penny-pinching and cost-cutting – and that’s a great shame, given that a dedicated button makes using the camera so much easier (and quicker!) on other devices.
The Windows Phone app-gap is also as significant a problem here as on the rest of Microsoft’s range. The severity of that problem will be determined by each individual user, of course – not everyone cares about getting the latest apps at the same time as they’re available on other platforms, but many users do, and this isn’t something that will be solved overnight.
Microsoft is working hard to improve the situation, particularly with its new initiative to make it much easier for developers to port their apps from rival operating systems, but it will take some time for the effects of this to kick in. And let’s not forget that Microsoft has already been trying to sort this problem out for years, even declaring back in 2013 that the app-gap was finally closed. Try telling that to millions of Windows Phone users still waiting for the likes of Periscope, Pebble, Snapchat, HSBC, Barclaycard, Comixology, Tinder, Grindr, HBO GO, Odeon Cinemas, Official F1, Nike+, Virgin Atlantic Airways, Starbucks… you get the point.
But if you’re willing to overlook that issue – using mobile sites and third-party alternatives wherever possible – the Lumia 640 is an impressive device at an affordable price. In the UK, for example, it’s currently available for only £129.99 SIM-free, while in the US, it’s just gone on sale for $129.99, with no contract obligation, on Cricket Wireless.
With a free Office 365 Personal subscription for your PC (worth £59.99 / $69.99) thrown in, it’s hard to argue with the exceptional value that the Lumia 640 offers. And on top of this, Microsoft also confirmed recently that the device will be among the first to get a free upgrade to Windows 10 Mobile later this year.
The Lumia 640 isn’t perfect – which device is? – but there’s so much that it gets right. And with an impressive mix of solid performance, a good camera, a beautiful display and superb value, it’s a great choice for buyers looking for an affordable smartphone.
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Even a review as extensive as this one hasn't covered every single aspect of the device. Do you have any questions about Microsoft's Lumia 640? Ask them in the comments below or hit me up on Twitter @gcaweir, and I'll do my best to answer them!