Nokia has unveiled its range of Windows Phone 8.1 smartphones so here's our hands-on review of the Nokia Lumia 630 and Lumia 635.

As expected, Nokia has updated its smartphone line-up with some new Lumia handsets running on the freshly announced Windows Phone 8.1 operating system. The Lumia 630 and Lumia 635 are the two more affordable options while the Lumia 930 is the firm's new flagship device.

Nokia Lumia 630 and Lumia 635: Design and build

Like the Nokia X, the Lumia 630 and 635 come in a bright green colour but Nokia is also introducing a bright orange option. The firm is not scared to be bold with its colour palette with also a bright yellow available. If you can't handle the kind of look then black and white will also be on offer.

There's little to say about the design of the new Lumia devices since they carry the same look and feel as previous devices from Nokia. A plastic interchangeable shell makes up most of the phone, while the front is entirely glass.

The Lumia 630 and Lumia 630 feel relatively nice in the hand but don't fell particularly premium. They are more affordable than the Lumia 930 with Nokia stating that the 630 will cost $169 and the 635 at $189. The pair will launch in May.

One thing to note is that Nokia has dropped the dedicated camera button which comes on its other Lumia devices which is a shame.

Nokia Lumia 635 rear

Nokia Lumia 630 vs Lumia 635: What's the difference?

We've included both these device in one review because they are very similar smartphones, as the slight model variation suggests. However, there are a couple of differences to make you aware of.

A minor difference is that the Lumia 630 comes with a matt finish plastic shell while the Lumia 635 has a glossy coating. Since you can buy different interchangeable shells, there's nothing stopping you mixing and matching.

The more important variation is that the Lumia 630 is limited to 3G data while the Lumia 635 adds support for 4G LTE networks. For some markets, the Lumia 630 will be available in a dual-SIM model.

Nokia Lumia 630 and Lumia 635: Hardware

Aside from the mobile data difference, the two Lumia smartphones share the same specifications. They're powered by a 1.2GHz Qualcomm Snapdragon 400 quad-core processor and 512MB of RAM. That might not sound like much memory but the phone seems to run smoothly based on our hands-on time.

There's only 8GB of internal storage but matching new flagships like the Galaxy S5 and HTC One M8, the Lumia 630 and Lumia 635 come equipped with a microSD card slot which is capable of taking up to 128GB. As per usual, you can get 7GB of free OneDrive cloud storage.

Nokia Lumia 635 start screen

These days a 4.5in screen is a nice middle of the road size where the phone fits in your hand nicely but the display is still big enough to browse the web and watch videos without squinting. The IPS panel offers decent viewing angles and Nokia's ClearBlack technology remains excellent for contrast but a resolution just 480 x 854 is nothing to get excited about.

A 5Mp camera sits at the back of the device and as we mentioned earlier, there's no dedicated camera button. A few tests shots at Nokia's London office came out ok but there's nothing to write home about in this area.

Nokia Lumia 630 and Lumia 635: Software

As we mentioned at the beginning, the Lumia 630 and Lumia 635 come pre-loaded with Windows Phone 8.1 which is the latest version of Microsoft's mobile operating system. Although an update will be rolled out to existing Lumia devices, it won't arrive for a few months.

For starters, you can have up to six columns of tiles on the Start Screen and you can also choose an image as a background to them instead of picking a block colour. There's a nice parallax effect which looks great and makes the phone feel more personal (see above).

A headline new feature is the Action Center (below) which finally brings notifications to Windows Phone. Like iOS and Android, it's accessed by swiping downwards from the top of the screen. You can choose which apps you want notifications to appear from and there are also four tiles for quick settings which you can customise.

Nokia Lumia 635 Action Center

There are other tweaks too such as more lockscreen themes, a new calendar which integrates weather (genius), the Word Flow keyboard offers personalised predictive text and swipe style gesture typing. A set of Sense (not HTC) features help you manage data usage, storage and Wi-Fi.

Cortana is Microsoft's answer to Siri and the firm says it's the first 'true personal assistant on a phone'. Unfortunately we haven't been able to test it out as Cortana will launch in the US as a beta, in the UK and China later in 2014 and in other countries in 2015.

All of this is a big step in the right direction for Windows Phone 8 and its mission to catch up with iOS and Android. We like a lot of the new features but there still remains the issue of a lack of app support which is where Microsoft's rivals are still leagues ahead.

OUR VERDICT

We're waiting for a price on the Lumia 630 and Lumia 635 but with new Windows Phone 8.1 features, they could be set to be decent mid-range or budget smartphones.