With a full HD 5-inch screen and an amazing camera, plus a new version of the Windows Phone operating system on board, this could be the first Lumia that stands a chance of giving premium Android handsets a run for their money. And two new low-cost phones could really shake things up at the other end of the market, too.

Taking to the stage at the Microsoft BUILD conference in California, Stephen Elop, executive vice president of Nokia's Devices & Services also revealed two new budget handsets -- the Nokia Lumia 630 and Nokia Lumia 635. "Today we are introducing people to the best of Lumia and the best of Microsoft through three stunning devices based on Windows Phone 8.1. In addition to the new developments from Microsoft, Nokia is delivering people an uncompromised imaging experience, great design and better business phones," he said.

Bold words, but nearly two years on the Windows Phone platform is finally making waves in the smartphone market and is comfortably the third most popular operating system behind Apple's iOS and Android, knocking BlackBerry into a distant fourth in the process.

Lumia handsets sport great design and while their operating system has been lacking -- simply because it is much less mature than that of its competition -- they boast incredible imaging performance and sport essentially the best cameras available on any current range of smartphones.

With the Lumia 930, Nokia is not resting on its laurels in that respect. As well a great quality screen, the phone packs a 20-megapixel PureView camera, optical image stabilization (OIS) and ZEISS optics. And thanks to an array of supporting software functions and apps, it can keep pictures ‘live' after they've been taken, meaning users can refocus captured images or zoom in or out of them.

When it comes to moving images, the phone shoots full HD video and has four microphones for surround sound that automatically filters out sounds coming from directions other than where the lens is pointing.

The phone also has wireless charging as standard and uses a quad-core Snapdragon processor. All of which makes it fast and practical.

However, the Achilles heel of all Lumia devices thus far has been apps. No matter how good each handset's specs have been, smartphones are all about apps. The latest data from Flurry, published this week, reveals that the average US smartphone owner spends two hours and 19 minutes a day using apps, and that gaming, social media, social messaging and entertainment are the most popular app types -- 32 percent of all time spent using a smartphone is spent gaming.

And until very recently, the Windows Phone app store has been a rather barren place compared with Google Play and Apple's App Store (each offer 1 million+ apps and counting). However there are now 250,000 apps available. That's still a tiny amount compared to the competition, but is almost double what was on offer 12 months ago. And, this number is expected to explode in the coming months as Microsoft plans to create a unified app platform so that app titles will work across its phones, PCs and its Xbox games console.

While the 930 is firmly focused on competing with the Samsung Galaxy S5 and HTC One (M8), the Nokia Lumia 630 and Nokia Lumia 635 are there to shake up the entry-level market.

Both pack quad-core processors and feel like Microsoft's answer to the Moto X or Moto G. Both also sport 4.5-inch displays, and offer interchangeable, brightly colored rear cases. They also have built-in health tracking capabilities via something called SensorCore.

But perhaps the feature that will get potential owners most excited is their price. The Lumia 630 will cost $159 with a single SIM card slot from May, while the 4G/LTE 635 will cost $189 when it launches globally in the summer.

The Nokia Lumia 930 on the other hand, is priced at $599 before taxes and subsidies. It will be available from June -- beginning in Europe, Asia, India, Middle East and Latin America -- and will continue to roll out around the world (except the US) throughout the summer.