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The essentials
One thing, among many others, that Nokia phones were always known for was the (relatively) crystal clarity of voice calls its devices were capable of.
Throughout the Lumia line, this has been something of an understated, but crowning feature, and happily the Microsoft Lumia 640 continues in this tradition.
Calls made from the device were pleasantly loud and rounded, and callers remarked on the quality at the other end. Though not quite up to par with the likes of 'HD' voice calls offered by some network providers, the Lumia 640 is a pleasant call-making device indeed.
Radio performance also proved to be something of a high point, with clear HSDPA+ performance across the Bath, Bristol, Swindon and Cardiff areas. This proved to be true even in areas where I have often found it difficult to gain reception.
Pages loaded quickly on the baked-in Internet Explorer browser, though the app has some issues with 'pop-in'. Microsoft has tinkered with the code behind this to mimic Safari, and as such performance is similar on many sites to Apple's native browser.
With a configurable reading mode, desktop mode and many other settings, the browser is moderately customisable, which will no doubt please tinkerers. And with a bottom-mounted address bar, one-handed use is a very practical option.
Aided by the generously spaced keys of the on-screen keyboard, along with the fluid and reliable gesture mode and predictive text functions, the Windows Phone typing experience remains a joy. This remains true even in the face of increasingly serious competition in the Android space from the likes of Swiftkey and Swype.
The rear-facing speakers on the device produced a satisfying level of volume, with noticeable distortion not making itself known until the highest levels.
Finding apps on Windows Phone remains something of a problem. If they are available at all, apps are often a little more limited or buggy than their counterparts on other mobile operating systems, very rarely receiving updates.
Lastly, but not least, GPS performance on the device was acceptable. No matter where I found myself, getting a lock and navigating elsewhere was always a quick experience, with little in the way of jitters or lag.
Camera
With higher-resolution sensors quickly becoming the norm, even at the lower-end of the mobile market, on paper the 8MP sensor of the Lumia 640 fails to impress.
Yet, in most real-life situations, the camera unit in the Lumia 640 is a strong contender for the best snapper in the budget space.
In good lighting, the sensor produced strong levels of detail, along with colours that had a pleasing 'pop' without excessive saturation.
Coming with Windows Phone 8.1 Update 2, the Microsoft Lumia 640 is also privy to another exciting feature that first made its debut on higher-end phones in the Lumia line: 'Rich Capture'.
For the uninitiated, this is simply HDR (high dynamic range) but rebranded. When activated, this allows the camera to compensate for high levels of contrast; for example, pulling more detail out of dark shadows on brightly lit days.
With Microsoft's example of the service, however, this also allows you to select 'how much' flash you would like in your low-light shots, improving performance somewhat. The sensor captures two images, one without flash and one with, and combines the two afterwards to achieve the most pleasing result.
Despite this neat trick, low-light photography is not a highlight of the device. Although there is a decent level of brightness in most shots, noise constantly rears its ugly head in almost every scene.
There's a single 0.9 MP selfie camera on the front of the device, and this – as might be expected – is perfectly acceptable for the odd Skype call, but not for much else. It is certainly not on a par with the likes of the 5MP wide-angle effort on the Lumia 535 and the Lumia 735.
Video is also of decent quality, with the camera handling differences in contrast well and with decent sound levels. Footage can be recorded in 1080p and 720p at 24, 25 and 30 FPS.
At such a low price, and with such competitive specifications in so many other areas, Microsoft might have been content to produce something merely average. However, the Lumia 640 is a good all-round smartphone snapper.
