The iPhone camera is great, but theres a limit to what it can do. For example, its built-in panorama mode is one of the best around, but it only shoots horizontal ‘flat’ panoramas, and meanwhile the world is waking up to the incredible potential of 360-degree spherical imaging.

Right now there’s no shortage of 360-degree cameras, but what’s unusual about the iON 360U is that it clips straight on to an iPhone 7, iPhone 7 Plus or a Galaxy S8 or S8+.

Actually, it does more than just clip on. In fact the iON 360U is both a case and a camera. You slide your phone into the case (which has a rather elegant brushed metal finish, by the way) and clip the camera unit on the top when you want to shoot spherical images.

So here’s how it works. First, you fit your phone in the case (top left). You can use your phone perfectly normally like this, though we couldn’t plug our iPhone’s earbuds in. Next (top right), you clip on the camera unit to shoot 360 stills or video. The camera unit (above) has dual 180-degree lenses which capture the 360-degree image between them.

The camera unit follows the usual 360 imaging format, with twin 180+ degree cameras producing hemispherical images which are stitched live by the camera to produce seamless spherical images and videos.

Stills are captured at 7.4-megapixel resolution and movies are in 4K. Both can be saved to your phone and accessed/played back within the app, and videos can be streamed live to Facebook and YouTube. We didn’t try the streaming, but we did shoot lots of spherical stills and videos as we tested out the camera.

For anyone who hasn’t tried 360 imaging before, it’s a disorientating experience. The iON 360 U shows the view pointing forward when you take the shot, but actually captures a spherical image, so it doesn’t exactly matter where you’re pointing the camera.

360 video is disconcerting too. The video plays back in real time, of course, but the viewer can choose where they want to look while this is going on. Not surprisingly, 360 stills and video don’t display in regular photo or movie apps – you need special 360 image apps or websites. So to ‘explore’ your spherical content on your phone, for example, you’ll need to do it within the iON 360U app – you can’t just save these to Photos and expect it to play them back with full interaction.

The build quality and finish of both the camera and the case are first rate. Both the video and the stills captured by the iON 360U are fine for sharing and browsing on your phone, though when it’s stretched over 360 degrees, 7.4 megapixels and 4K video are stretched pretty thin, so the definition has its limits. There are just a couple of little niggles, too.

iON 360U review

Here are just three views of the same scene. It’s really intuitive playing them back in the iON 360U app because you pan around the scene simply by turning and tilting your phone. It’s like wearing VR goggles without, er, the goggles. The resolution is fine for viewing on your phone, but it soon peters out if you zoom in or view the scene on a larger screen. It’s possible to see the ‘join’ between the two lenses in these images too – a band of softness running vertically/diagonally down the frame.

First, the camera unit often needed to be shoved into contact with the case quite hard before the camera unit was recognised. Second, the case plugs into the iPhone’s Lightning socket without offering a pass-through connector for headphones – there is a connector, but it’s for a USB cable. That’s fine for charging, but if you want to listen to some music you’ll need to take the phone out of the case.

Interestingly, the case does include its own 1260mAh battery to power both the camera and your phone, though extensive use does drain it pretty fast.

The other niggle is that the app does not have a self-timer function, so any 360 video or stills will have you featuring pretty prominently in the frame, with a weird mutant hand outstretched towards the viewer’s position – the camera blots itself and your phone out of the frame very effective, but not the whole of your hand.

The solution here is to use a selfie stick, which solves the video problem, but not the stills problem – so hopefully the company will update the app with a self-timer soon.

Otherwise, the iON 360U is a whole lot of fun. It’s not especially cheap, but it’s clever and nicely made and 360 imaging, when it’s made so easy to shoot and play back on your own phone, is extremely addictive.

The iON 360U costs £299.99 and you can buy it direct from uk.ion360.com – make sure you specify your phone brand and model.