Smartphone displays have rapidly improved at every single price point. Inexpensive smartphones often compromised on display quality, which ended up hurting much of the overall experience. However, even inexpensive smartphones now ship with IPS displays and high enough resolutions to render text without overwhelming aliasing.

The Lumia 640 has a 5" 1280x720 IPS display. At 294 pixels per inch, it’s fairly sharp for a phone of this price. It’s obviously not some 2560x1440 flagship phone, but I never felt like text appeared fuzzy or highly aliased. To evaluated the aspects of display quality beyond what you’ll see on a spec sheet we turn to our standard smartphone display tests. As always, measurements are performed with X-Rite's i1Pro 2 spectrophotometer and SpectraCal's CalMAN 5 software, with the exception of contrast measurements which are done with an i1Display Pro colorimeter.

Display - Max Brightness

Display - Black Levels

Display - Contrast Ratio

437 nits is a fairly good result for peak brightness. It’s not quite as high as the 500 and 600nit displays that you’ll see on flagship phones, but it’s noticeably higher than many other devices at this price point. The contrast is also pretty good. While the black level isn’t even close to the lowest we’ve seen, when you consider that many devices use CABC to cheat on contrast it’s actually a relatively good result.

Display - White Point

Display - Grayscale Accuracy

The greyscale results on the Lumia 640 are exceptional. RGB balance is great at every shade of grey, with only a very slight shift toward blue. All of the errors will only be visible if you compare static images with a reference monitor. There’s not much more to be said, as the greyscale accuracy on this display is essentially perfect.

Display - Saturation Accuracy

The next test examines saturations of primary and secondary colors on the display in increments of 20%. In this test the Lumia 640 does very well. There are definitely some issues with blue and magenta, and the fact that cyan maxes out at 80% saturation, but the overall accuracy is very good.

Display - GMB Accuracy

The final display benchmark is the Gretag MacBeth ColorChecker test. This test examines colors that are commonly found in the real world, and it’s the best benchmark of display color rendition. A display can hit its saturation targets accurately but fail to reproduce these color mixtures properly.

Fortunately, the Lumia 640 suffers from no such issues. Most of the colors are reproduced with a high degree of accuracy, with the big errors being in shades of blue. Skin tones are very well reproduced, which is something I’ve seen other devices struggling with in recent reviews.

Overall, the Lumia 640’s display is very good, and I would go as far as to say that it’s one of the best displays on a phone at this price point. It performs well in every category, from brightness, to contrast, to color accuracy, and the resolution is high enough to keep everything looking fairly sharp. I think Lumia 640 users will be very happy with the display on their phone.

System Performance Camera Architecture and UX
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  • testbug00 - Tuesday, June 9, 2015 - link

    Just one FYI, Glance has multiple modes, including "peek" where it only activates when it detects something moving over it (or leaving a space where it always is 'sensing' something (IE, a pocket)

    And, yeah. Windows Phone uses a lot of battery life to have Wifi on. Dunno why. Even without any MS account on it and no non-native apps it still eats 2-2.5% of battery on 920. Haven't tested on other WP devices.
  • BrokenCrayons - Tuesday, June 9, 2015 - link

    Nice phone for a good price, but it's positively huge with a 5 inch screen. Its disappointing that it's impossible to find a phone with decent specifications and a 3.5 inch screen. I can't imagine carrying this or any other phone that big around. I'd be tempted to tape a stick to it and use it as an oar.
  • kyuu - Tuesday, June 9, 2015 - link

    As someone whose smartphone history is iPhone 4, Lumia 920, and now Lumia 1520, I can tell you that once you've used a bigger smartphone (1520 has a 6" screen), you cannot go back to the small ones. They feel like toys and browsing the internet or watching videos on them is intolerable.
  • Daniel Egger - Tuesday, June 9, 2015 - link

    Get a 735 then. It's a very nice piece and noticeably smaller than the 640 plus it has an AMOLED display. It's a bit larger than my 820 which for me has about the perfect screen size but it's thinner and much lighter (especially since it has Qi built-in rather than needing a special cover which adds additional bulk and weight).
  • MrSpadge - Tuesday, June 9, 2015 - link

    Consider the Lumia 435 then. Internally it's not much different from the 640 if you can live with a few compromises.
  • paulheu - Tuesday, June 9, 2015 - link

    Google does not just not make any apps for Windows Phone, it actively blocks anyone else from doing the same if at all possible. Hopefully with Windows 10 this will change due to the very nature of that OS . We'll see..

    The remarks on Glance probably come from not having the extension app loaded which allows for backgrounds and more options.
  • Brandon Chester - Tuesday, June 9, 2015 - link

    The Glance Screen app doesn't show up in the store for all Windows Phones, Lumia 640 included. If you look at the list of Microsoft apps when browsing the store on the phone it's just not even there.
  • MATHEOS - Tuesday, June 9, 2015 - link

    You definitely should have rating system!
  • atata - Tuesday, June 9, 2015 - link

    I've had this phone for several months and it feels great after Lumia 525. I certainly don't see the battery drain mentioned in this review, but I don't use most of fancy mobile apps aside from Viber.
  • lilmoe - Tuesday, June 9, 2015 - link

    "Microsoft's scroll speed cap also makes the entire operating system feel slow"

    This issue is so underrated, and I believe (even with your criticism) that you were very diplomatic in your complaint. This is BY FAR my biggest issue with Windows Phone and I've nagged Microsoft so many times on uservoice and the feedback app about the speed of scrolling and inertia settings (speed and feel of the "flick"). Not only does it feel slow, it's also not even close to being natural.

    iOS is slower than my liking too, but it feels more natural in a sense. I believe Samsung got the speed and the "flick" right with their devices, and Android followed after JellyBean. Microsoft needs to blatantly copy Android in that department, and screw what people say.

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