We had known for some time that the Huawei P30 Pro was coming 26 March - we've seen the handset, check out our full preview here - but are still amused at how the company CEO, Richard Yu, prematurely posted a picture on Weibo showing the phone will feature four cameras. How about that as straight from the horse's mouth?

But the P30 Pro isn't the first phone to reveal four rear cameras, that goes to the Samsung Galaxy A9. So is the multiplication of cameras on phones due to become the new norm? We look at why the setup exists, what's available, and what's thought to be coming (if the rumour mill is accurate).

Why have four cameras?

Simply put, more lenses means more variety. 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.

The Huawei P30 Pro, which features a 5x periscope zoom lens, means you can zoom even further in on the action without loss (or to 10x with hybrid zoom). In addition to its standard and wide-angle lens, the fourth to make up to quad selection is time-of-flight (TOF) infrared optic.

So what's a ToF camera? It's a Sonar-like solution, used to capture depth data, a bit like how a bat would read its surroundings. That data can then be used in the software to apply background blur while keeping the main subject sharp - what Apple calls 'Portrait' mode, basically, and what so many others have delivered (arguably even better).

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 (although the S10+ didn't go down the route). 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

New for March 2019, the P30 Pro is the first to market with a true 5x optical zoom, which uses a periscope camera. We've seen Oppo teasing such tech before, but that brand has been beaten to the punch.

The P30 Pro is therefore the most versatile camera phone on the market, delivering that zoom, an ultra-wide lens, alongside its more standard lens and ToF optic, making up a highly capable foursome. The 'standard' P30 doesn't offer a four-camera setup.

Nokia 9 PureView

Nokia 9 PureView initial review image 11

Ok, ok, we're cheating here a bit, as the Nokia 9 doesn't have four cameras - it has five (hence 'penta'). But it supports our point: if five is Nokia's top-end standard then four-camera phones from other flagships in the near future seem all the more likely.

However, the PureView approach is somewhat different to its wide/zoom competitors, its focus is all about quality. With multiple monochrome and colour sensors, it can combine capture from all its lenses and process data for ultimate quality, rather than delivering the most versatile use case. Still, that's a sound approach and it's exciting to be different.

Conclusion: Do you need four cameras?

The trick to all this is ease of use and design subtlety. We don't think people want to say 'I have more cameras than you', they want the broadest capability from their phone. At the moment, it's multiple cameras that achieve that, until some new-fangled technology comes out that can hide away the various openings and bumps on phones' rears.

So, do you need a four-camera phone? It's not essential. But if you want true wide-angle and true optical zoom or the utmost quality then it's the best solution right now - with the Huawei P30 Pro leading the way. Mark our words, there'll be many more multi-camera phones before the year is out.