The Microsoft Lumia 640 Review
by Brandon Chester on June 9, 2015 8:00 AM EST- Posted in
- Smartphones
- Microsoft
- Mobile
- Lumia
- windows phone 8
Still Image Performance
Now that we’ve gotten the basics of the Lumia 640’s camera system and camera software out of the way, we can move on to evaluating the actual image quality. The most relevant phone to compare to will be Motorola’s Moto E, which sells for around the same price but sports only a 5MP rear-facing camera.
The first photo comparison is the standard daylight test scene that I use. The branches of the trees in the frame are a good test of spatial resolution, while the various different textures can be examined to see how the phone handles noise reduction and maintains detail during processing.
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With ample lighting, the Lumia 640 performs very well considering its price. I do find that the Lumia 640’s white balance tends just a tiny bit too far toward yellow in this case, and colors are a bit undersaturated, but the overall image quality is pretty good. When you compare it to the Moto E, it’s clear that the Lumia 640 is much sharper across the entire frame, and ends up maintaining much more detail. A good example is the brick texture of the red building on the left, which is maintained in the Lumia 640’s shot but completely scrubbed away in the Moto E’s photo.
As for comparisons to other 8MP smartphones, the Lumia 640 tends to fall behind when it comes to sharpness. The Nexus 5 with its larger sensor ends up capturing the tiny interlocking branches of the trees with much more sharpness, and maintains the black bars of the furthest gate on the left which have become a grey unresolved area in the Lumia 640’s photo. This doesn’t mean that the Lumia 640 performs poorly relative to its price. On the contrary, its performance in daylight is extremely good for a $129 device.
While even the most inexpensive devices can now produce usable photos when there's good lighting available, low light photos tend to be where devices stumble. To see how the Lumia 640 performs in low light, I've taken photos of the same scene as above but at night. With the sun having set, the only sources of light in the frame are a handful of lamps on buildings and along the red brick road.
In the low light scene, the Lumia 640 actually performs better than I had expected. I would say it actually outperforms the Nexus 5. While it doesn't show as much in the scene as the Nexus 5 due to its exposure, and not near as much as the iPhone 5s, it has very fine noise and good sharpness in the areas that are exposed. The Nexus 5 by comparison shows a small bit of the sky and the leaves of the first tree, but the entire image suffers from distracting chroma noise which ruins much of the detail. I certainly didn't expect this from a 1/4" sensor without OIS, and much of it is thanks to Microsoft's superb image processing. My one complaint is that there's a lot of flare from all of the light sources in the scene, and the lamp on the right is particularly distracting because of it.
As far as smartphones in the $100-150 range go, the Lumia 640 definitely has the best camera I've seen to date. The Moto E simply can't compete with its smaller 5MP sensor, and Microsoft's high quality image processing ends up producing photos that are better than the 13MP ZenFone 2 in many ways, which goes to show how a device's image processing is just as important to image quality as the actual sensor itself.
Video Performance
The other side of a phone's camera quality is how it performs when taking video. Taking videos is also arguably a more intensive test of a device's camera system than taking still photos, as device's image signal processor has only a short time to process images. There's also no way for devices with OIS to use it to enable long exposure times, as the exposure time for each frame can't be any more than 42ms, and usually less.
The Lumia 640 can capture 1080p video at 24, 25, and 30fps. For this test I opted for the 30fps mode, as the higher frame rate comes with less motion blur. The Lumia 640 encodes its 1080p30 video with an average bitrate of 17.6Mbps using the H.264 Main profile.
Video footage from the Lumia 640 ended up being quite decent. The bitrate is just as high as high end smartphones, and the footage isn't really any blurrier or noisier than what you'd get from something like the iPhone 6 at the same resolution and frame rate. My one complaint is that Microsoft's EIS doesn't seem quite as effective as the EIS that I've seen on other smartphones, and as a result the footage is a bit shakier. There are also some fairly dramatic changes in exposure and white balance when changing the target of the shot, and in certain circumstances such as when the camera is being pointed at red flowers it actually ends up making the video look too cold. However, the overall video quality is very good, and is miles ahead of other inexpensive devices that I've looked at recently like the ZenFone 2 and the Moto E.
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tuxRoller - Wednesday, June 10, 2015 - link
Does anyone know why wp is so, relatively, inefficient?I'd been told that wp was going to offer so much better battery life than android b/c it didn't require a vm:)
MrSpadge - Wednesday, June 10, 2015 - link
In the test the glance screen with the LCD being always on probably killed idle battery life. The load results seem fine, but could certainly use a boost from a faster browser.Margalus - Wednesday, June 10, 2015 - link
I just switched to Window Phone, with a better phone and same size battery as my Android. The Windows phone batter lasts 5-8 times longer than the Android phone...Voldenuit - Wednesday, June 10, 2015 - link
"Windows Phone isn’t going anywhere"Ironic double entendre is ironic.
Margalus - Wednesday, June 10, 2015 - link
I just made the switch to a Windows phone 8.1 about a month ago. I bought the HTC One M8. Here is a tidbit of my opinion.One issue I have with this review is the scrolling speed on Windows. It must be specific to the this phone that is being reviewed here, not specific to Windows as the reviewer says. On my HTC One M8 Windows 8.1 I can scroll slow or fast. A gentle push and the screen scrolls slowly, a fast flick of the fingertip and the phone will scroll almost instantly to the bottom, too fast to see anything, just like my Android.
Going with the HTC One M8 and Windows was the best move I've ever made. The phone experience on Windows is so much better than Android (coming from an Galaxy S4) it's ridiculous. Everything is so much faster and smoother it's unbelievable. And I no longer have that stupid Android bug that would eat up the phones battery in 4 hours on occasion. On The best day with the S4 I could go about 24 hours before charging, on a high usage day, it would be dead by the afternoon and on a portable battery. When the bug hit, 4 hours or so and it was dead. This HTC One M8 with Windows will easily last 4 days with even heavier usage. I've just gotten into the habit of charging it on Mondays and Fridays, with no fear at all of running out of power, and that is with the battery saver feature disabled.. It's crazy how much better it is.
The phone app connects instantly, no delays like on my Android where I would hit a contact and sometimes wait 5 seconds for the phone to connect and dial.
It is missing a few apps I used on Android, and that is very disappointing. But the overall phone experience is so much better it's worth giving up a couple of those apps.
BabelHuber - Thursday, June 11, 2015 - link
Sorry, but what you are stating here is quite fishy:I have a Samsung Galaxy S4, under heavy use I get about 4h of screen on time. For light use, it can easily last 3 or even 4 days - the battery drains about 0.9% per hour if in deep sleep (albeit with an AOSP ROM, not the bloated Samsung original)
When a phone drains battery like there is no tomorrow, usually some app prevents the deep sleep of the phone. There are tools like GSAM Battery Monitor and Better Battery Stats in the Play Store to analyze this.
But lots of users prefer blaming Android instead of having a look at all the crap they have installed on their device, it is so much easier.
Also, your claim that the phone held only 4h on standbye really looks strange: To suck up the battery so fast, the load on the SoC would need to be incredibly high - such a phone would be _VERY_ warm - in fact so warm that you having a phone call would be displeasing!
As a matter of fact, the SGS4 holds quite long under some load if the screen is off - when I use WIFI tehering with the screen off, the battery consumption is about 10% per hour.
So if I assume that you posted true numbers (and not just some MS-propaganda), you either have bloated your phone with tons of crap software or your battery was broken.
Zizy - Thursday, June 11, 2015 - link
Bugs happen. That same bug he describes happened several times to my wife on Android and to me on WP.If you have phone in your pocked you usually notice this because the phone gets warm. If the phone lies on the table, you don't notice it until you pick the phone and see 0 battery left.
BabelHuber - Thursday, June 11, 2015 - link
You are correct, this also has happened to me once, albeit not so severe (the phone had ~5% per hour battery usage on standby or so)But instead of throwing a tantrum and blaming Android, I installed GSAM Battery Monitor Plus, found the App which caused the wakelocks and deinstalled it.
Alternatively, it is also possible to install a wakelock blocker. Then you don't have to deinstall the app, you just block its wakelocks.
Margalus - Thursday, June 11, 2015 - link
I didn't throw a tantrum, the tantrums are being thrown by people who apparently don't want anybody to criticize android. I'm sorry to say, android is not perfect.Margalus - Thursday, June 11, 2015 - link
You are the first person I have ever heard say that they could more than 24 hours with a galaxy s4, or any galaxy. That's why had the replaceable battery...