The prettiest flagship smartphones (pictures)

Smartphones need to be equal parts functional and fashionable if they're going to succeed in making their way into pockets the world over.

We take a look through the most beautiful phones of the moment and peek at some of thinking behind the design decisions made.

"The materials it's been made with, the remarkable precision with which it's been built -- never before have we built a product with this extraordinary level of fit and finish," boasts Apple's Jony Ive of the iPhone 5 and iPhone 5S.

Apple loves making a big deal of its precise attention to detail in the design and production of its products and nowhere is this more the case than in the iPhone 5S.

"We've developed manufacturing processes that are our most complex and ambitious. The variances between product to product we now measure in microns," says Ive. "We believe that going to these extreme lengths is the only way we can deliver this level of quality."

"We don't want to make a new phone, we want to make a much better phone. iPhone 5 is the result of this approach. It's been completely redesigned," says Ive, explaining the bigger screen of the iPhone 5.

"Even with the larger display, it's the thinnest, lightest iPhone we've ever built."

"We began with a design we really love, but to build it, to implement it, we had to look way beyond what we knew to be possible," Ive says.

Sony has opted for metal for the Xperia Z2, as well as toughened glass front and back panels.

Sony claims the metal and glass design gives the phone a "slimmer and more comfortable feel", while the waterproofing "blends beauty with function".

Sony reckons you'll hit the power button 70 times per day on average. It therefore wanted to make it "just perfect", which presumably means making it stick out so it's easier to find.

The metal band has had to accommodate a dedicated camera shutter button, as the display won't register your taps and swipes when underwater.

The Z2 has an extremely minimalist design. It's one that I'm personally very fond of.

Ah, the HTC One M8. Like its predecessor, it has a metal body, but the new model wraps the aluminium around the edge to join the screen.

"The M8 is the epitome of a lot of the design principles we have been working with over the past decade," HTC says. "We took that metal housing and we were able to wrap it all the way around to the screen, completely eliminating all of the polycarbonate sidewalls that we had before.

"In your hand, you can feel the authenticity of the materials... the rigidity and the strength."

"It's interesting to see how we've had to take something that was actually quite good and take that to the next level," says Claude Zellweger, HTC's associate vice president of design, rather underselling the previous-generation HTC One.

"When you hold the phone in your hand you don't feel any hard edge anymore," says Zellweger. "That wouldn't have been possible without countless hours of work between the design team, the engineering teams and the antenna teams."

Although rumours circulated that Samsung was working on a flagship phone made from metal, the Galaxy S5 maintained the same plastic construction we've seen on previous Galaxy phones.

"It's about making evolutions that matter," explained Samsung's vice president for brand, Stephen Taylor. "I think the improvements to the covers, finishes and colours are a step forward for people.

"If you look at the feedback, it felt like making [the phone] more durable and keeping the sleek design was what people were after. Waterproof and dustproof elements are more important."

Speaking to Engadget about the choice of plastic over metal, senior product designer Dong Hun Kim said, "With the GS5, we looked into all kinds of designs and materials. We were open to all options."

"Our major aims were usability, friendliness and a more humanistic design," says Kim. "We wanted something with a pleasing feel... and better grip. With plastic, the texture is warmer... if we used metal, the designs felt heavy and cold."

The plastic body does also allow for the battery to be swapped out when the existing one starts to lose the ability to hold its charge.

Numerous design cues from previous Galaxy phones -- such as the silver-edged home button -- have remained on the Galaxy S5.