iPhone 6: What can you do that you can't on an iPhone 5s?

Is the new iPhone worth the upgrade? Here's everything you need to know about the new iPhone's killer features

Apple launched the iPhone 6 this week to a public eager to get their hands on their latest smartphone.

It has a range of new features, upgraded specifications - and the much talked about big screen and thinner body.

But if you already have an iPhone 5s, is it worth the upgrade? What can you actually do with an iPhone 6 that you can't do with a 5s?

Here's our guide to the improvements in the iPhone 6 and 6 Plus over last year's model.

Screen Size

The big selling point of the iPhone 6 and 6 Plus are the bigger screen sizes on offer.

The 4" screen of the iPhone 5 was already a big jump from the shorter screen of the iPhone 4 - but a lot of users found even this was too long for their thumbs.

But as well as making the screen bigger - allowing for more icons on the screen and more information to be displayed in apps - Apple have helpfully introduced a system which allows the 6 and 6 Plus to be easily used with one hand.

A light double tap of the home button scrolls the whole screen downward to allow easy access to the top row of icons.

The 6 Plus also allows apps to run in landscape mode, as is the case with iPad apps. This means that, for example, email apps can include a list of messages and a preview of the email in side-by-side panels on the same screen.

Performance

Apple doesn't tend to talk numbers when it comes to processor speeds and such, but the A7 chip and graphics hardware on the iPhone 5s have yet to show any signs of slowing down in the face of even the most advanced games and apps.

Of course, as time goes on and software gets more complex, you'll start to notice the difference - try running iOS 7 on an iPhone 4s if you want a demonstration.

Design

So as far as what's on offer right now, you'll probably not notice a huge difference. In a year or so, you almost certainly will.

The iPhone 5 and 5s were - and remain - the lightest phones Apple has ever made.

The 6 might be a few grams heavier, and certainly larger to accommodate the screen size, but it's actually thinner - just 0.27".

The overall design has been given a proper overhaul. It draws from the rounded edges of the iPad Air and Mini - and looks quite reminiscent of the original iPhone from the back. The slightly curved edges of the screen reportedly make swipe gestures much more comfortable, too.

Each iPhone breaks new ground in handheld device design, and the 6 is no exception.

Apple Pay

Apple have been working with credit card companies to come up with a way of paying for purchases with your phone. Apple Pay integrates with the Near Field Communications (NFC) technology in the iPhone 6 to allow you to tie your card to your phone, and make purchases with just a swipe.

Camera

Phil Schiller talks about the new iPhone 6 camera - still 8 megapixel but capable of immense detail, improved autofocus and colour correction only seen in high-spec digital SLRs.

The iPhone 6 camera has an 8MP sensor - the same resolution as the 5S. But it's not all about the numbers. The 6 may take pictures the same size as the 5S, but Apple claim improvements to the sensor have improved picture quality noticeably. The introduction of "focus pixels" speeds up the auto-focus process significantly.

And the introduction of image stabilisation - handled digitally on the 6, but with a much better optical system on the 6 Plus - makes for sharper pictures in low light.

Slow Motion Camera

When it was introduced with the 5s, slow motion video was among the must-see features. It lets you record video at high framerates, and slow it down at will to create a "bullet time" effect.

The 5s camera, which recorded at 120fps, was impressive. The 6 doubles that to 240fps. We've only seen the demo from the launch event, but it looks amazing.