We already know the Huawei P30 series is coming 26 March - the official invite is out, with the unveil due in Paris - but more details of the handset are emerging from the unlikeliest of sources: Richard Yu, CEO of Huawei Technologies Consumer Business Group, posted a picture on Weibo showing the phone will feature four cameras.

How about that as straight from the horse's mouth? As with many Huawei phones it's possible to get a watermark imprint from the phone on each image, this particular one - visible through a loose attempt to scribble it out - clearly reads 'Huawei P30 Pro' and 'Leica Quad Camera'.

But it's not the first phone to reveal four rear cameras. So is it due to become the new norm? We look at why the setup exists, what's out there already, and what's thought to be coming (if the rumour mill is accurate).

Why have four cameras?

Simply put, more lenses means more variety. As we've seen with the Huawei P20 Pro, which features a 3x 'tele' lens, you can zoom in on the action without loss. The Huawei Mate 20 Pro features the opposite: a 0.6x ultra-wide lens that fits even more into the frame.

With a four camera setup you can offer a standard lens, a zoom and a wide-angle all wrapped into one. We've already seen that in the Samsung Galaxy A9, featured below.

So what about the other camera that makes up the fourth? Typically this is a low-resolution camera used for depth mapping, or a time-of-flight (TOF) infrared optic used for the same task. This depth data can then be used to determine where a subject sits within a frame, so software can apply background blur while keeping the main subject sharp - what Apple calls 'Portrait' mode, basically.

What's available and what's coming?

Samsung Galaxy A9

Pocket-lintSamsung Galaxy A9 initial review image 1

The first four-camera phone to market, the A9 isn't Samsung's flagship, thus it seems like a testbed for a hardware setup like this. There's also a three camera A7 and a two camera A5 in the range, to offer something for everyone.

The A9 uses a standard, wide-angle, tele and depth sensor to make up its four cameras. That adds a lot of versatility when it comes to framing a shot without losing detail when zooming, or applying blur in Portrait mode.

Huawei P30 Pro

SlashLeaksAre four-camera phones the new norm Huawei P30 Pro image 1

No offical picture of this one yet (the above leak is conjecture), as it's not been seen in the wild. But as Huawei CEO, Richard Yu, has effectively confirmed, the P30 Pro will come with a Leica Quad Camera setup. The Leica part there is important, ensuring quality is assured for sake of sharpness, but what those four optics will actually do is yet to be confirmed.

The Weibo photo posted by Yu is a close-up of the moon, which would suggest a much longer 'tele' lens than the current 2x or 3x standard - so perhaps that's what we'll see? Time will tell, with the 26 March launch date when all will be revealed.

Nokia 9 PureView

Evan BlassNokia 9 Specs Release Date News And Rumours All The Latest About Nokias Next Phone image 1

Ok, ok, we're cheating here a bit, as the Nokia 9 hasn't been revealed just yet and it doesn't have four cameras - it has five (penta). Talk about getting a step ahead, eh?

But it supports our point: if five is Nokia's top-end standard then four-camera phones from other flagships in the near future seems all the more likely.