Galaxy S6 and S6 Edge meet their predecessors

The Galaxy S6 and S6 Edge are a major design departure for Samsung, ditching its favoured plastic casing for metal and glass. We've put the new models next to their predecessors, to better examine how Samsung's design ethos has changed.

Samsung honed its design chops back in 2012, with its Galaxy S3.

The S3 was a revelation at the time, with a standout oval shape and a huge screen.

The S3 still stands as a great smartphone, and it was the device that proved Samsung had the power to create something a bit different.

The Galaxy S4 in 2013 kept the same basic look, but made the corners a little more square, and increased the screen size to 5 inches.

The S4 was a good-looking phone, but by this point, many onlookers were craving the premium feel of more luxurious materials than Samsung's preferred plastic.

The Galaxy S5, released in 2014, was a more controversial move, in design terms.

While it was tough to criticise the S5 in terms of its raw power or list of features, its grille-like plastic edges didn't impress everyone.

Likewise, the peculiarly-textured back of the S5 didn't feel quite as posh as rival smartphones, which were deploying heady amounts of metal and glass in their construction.

This year however, that's all changed, because the S6 and S6 Edge, which has two curved sides, ditch the plastic in favour of metal and glass. The trade-off, however, is that the battery in these phones is no longer removable, but permanently sealed inside the phone.

Here are the S6 and S6 Edge next to their predecessors.

The glass on the latter two smartphones give them a much glossier look.

The sides of the phone have seen perhaps the biggest shift. The S6 Edge has swooping, curved sides, while the S6's side is more rounded and less shear than its forebears.

It'll be interesting to see whether the phone-buying masses think a non-removable battery and no option to upgrade memory is a worthwhile trade for a more luxurious design.

Samsung's changes aren't all external. The S6 and S6 Edge have been given a software makeover too, which Samsung hopes will make them simpler to use.

Samsung has managed to maintain its position as a major smartphone maker, despite years of intense competition. However, the stakes are higher than ever.

We have plenty more to say about the S6 and S6 Edge, so be sure to check out more of our coverage.