Samsung Galaxy S4 vs Galaxy S3: What's changed?

After months of sleepless nights and anxious waiting, the Samsung Galaxy S4 is finally a real device that you'll soon be able to acquire in exchange for precious, precious money. But how is the Galaxy S4 different from the Galaxy S3?

Similar design, but subtle tweaks

Not a lot has changed from the S3 in design terms, and Samsung has stuck with the rounded, pebble-shaped style that it debuted last year. Visually the S4 looks a lot like its predecessor, but has a flatter back and a neater, more uniform shape.

Despite rumours to the contrary, Samsung hasn't ditched the home button, opting to keep a mechanical key nestled 'neath the S4's screen. The bezel surrounding the screen has been slimmed down, meaning you'll be looking at more screen and less plastic. The S4 is also both slimmer and lighter than its forebear, despite being larger overall.

Available colours have been given a shake-up, and while the S3 originally came in blue and white, the S4 comes in more traditional black and white -- or 'black mist' and 'white frost', if you prefer Samsung's daft colour conventions.

Bigger, higher-res screen

The S3 was no slouch in the display department, but the S4 takes things to the next level with a 5-inch, 1080p Super AMOLED display. Pixel density is dramatically increased from 306ppi on the S3 to 441ppi on the S4, meaning onscreen text and images should look razor-sharp.

Eye-control and hover gestures

Samsung always goes big on bespoke software, and has crammed the S4 with eye-control features such as Smart Pause which pauses video when you look away, and resumes the clip when you look back. Eye-tracking gestures are in place, while you can scroll through content by tilting up or down.

As if that's not oddly futuristic enough, you can control the S4 by hovering your hand over the screen. This works in the browser as a magnifier, or you can wave your hand in front of the phone to accept a call -- handy if you're driving as it goes into speakerphone automatically. You don't have to hold your hand too close to the phone to make this hovering tech work.

It remains to be seen whether Samsung will update the Galaxy S3 to bring these new features to its older mobile. Fingers crossed though. The S4 contains even more bizarre apps -- check our in-depth preview for more.

Tonnes of camera features

Samsung has followed the lead of HTC and Nokia, pumping its new smart phone full of camera tricks, including a dual-shot model that takes a shot with both the rear and front-facing cameras, combining the two shots into one image. The front-facing snap will be placed as an inset, so you can see your reaction to taking a photo as well as your subject. Useful... maybe.

Sound and Shot takes a picture with 9 seconds of accompanying audio, while Drama Shot combines burst shots into one image, giving you multi-stage action photos, handy for capturing pets or feats of sporting prowess.

Cinema Photo creates a static image with specified bits of the picture continuing to move (think Cinemagram) and exports this picture as a .gif, while Eraser Shot removes people from your photos. Yikes.

The camera itself has a 13-megapixel sensor, up from 8 megapixels on the S3. Pixel count alone doesn't necessarily indicate better quality snaps, but rest assured we'll be putting the S4's snapper through its paces during the full review.

Faster processor and 4G

Exactly what kind of processor you find in the Galaxy S4 will vary depending on your region, with some countries getting a quad-core Qualcomm processor and some getting Samsung's own-brand Exynos 5 octa-core processor.

We'll need to perform our own tests before we know how much more powerful these chips are than the S3's quad-core processor, but as there's still very little out there that can push the Galaxy S3 to its limits, I'm confident this will be one of the snappiest smart phones out there. You get 2GB of RAM thrown in for good measure.

The S4 is LTE-capable, so you'll be able to hook onto the 4G networks that are starting to spring up. This is something the S3 didn't manage, but its sort-of-sequel Galaxy S3 LTE could handle.

Different enough?

So, a host of crazy apps, a slightly bigger screen and more power under the bonnet -- but is that enough new tech? For the most part, the software on board both the S3 and S4 will be broadly the same, as both mobiles are running versions of Android Jelly Bean that have been smothered in Samsung's own TouchWiz interface.

The design is very similar, which could prove divisive, as many Android fans weren't too chuffed with the plastic casing that ensconced the Galaxy S3.

Do you think the S4 is a good enough update, or is Samsung getting complacent? Let me know your thoughts in the comments, or on our Facebook wall.