Samsung Galaxy S4 vs Galaxy S3

I claimed the Galaxy S3 to be the best smartphone on the market when it went on sale in June last year, beating the iPhone 4S which suddenly felt too small, too heavy and lacking the visual 'wow' of the S3.

As much a demonstration of how easily I'll change my mind as how quickly the smartphone market is evolving, the iPhone 5 came along six months later and by year-end it had put Apple back to number one.

Now it's Samsung's turn to beat Apple and itself again, with the 5in Galaxy S4 announced in New York this week.

Display

When Samsung launched the Galaxy S3 last year it was considered an enormous phone, larger even than the HTC One X and dwarfing all previous iPhones. 'How would such a phone be usable?' we demanded.

Well it turns out Samsung was probably right in making the 4.8in S3, and I even grew to love the almost ridiculous 5.55in Galaxy Note 2, so the 5in Galaxy S4 comes as no surprise.

Thanks to a slight reduction in thickness you will be hard-pressed to notice the extra 0.2in of screen real estate, although for anyone making the jump for a 3.5in iPhone or similar it'll take some getting used to.

Once you have, the S4 has a full HD 1080 x 1920 resolution and a pixel density of 441 pixels per inch (ppi), significantly higher than the 720 x 1280 resolution and 306ppi of the Galaxy S3.

Above the 5in screen the Galaxy S4 has a 2.1-megapixel front-facing camera which builds on facial recognition technology first used in the S3 to offer 'Smart screen' features.

With these turned on the S4 monitors your eye movement so closely that pages can be scrolled up when you reach the bottom of a paragraph, and video is paused when you look away.

When reviewing the Galaxy S3 I turned off Smart Stay - keeping the screen unlocked until you look away - because it seemed pointless and even got in the way, but I read a lot on my phone, so if the screen can scroll automatically I can see me using the feature - and it means you can use the phone one-handed without fear of dropping it by stretching your thumb up to reach the display.

As for overall size and weight, the S4 measures 136.6 x 69.8 x 7.9mm, compared to the Galaxy S3 at 136.6 x 70.6 x 8.6; the Galaxy S4 is slightly lighter than the S3, weighing in at 130g compared to 133g.

Processor

Powered by an Exynos 5 Octa chip, the Galaxy S4 is technically a quad-core smartphone with eight cores at its disposal. Dubbed big.LITTLE, the phone can make use of a 1.6 GHz quad-core processor for heavy work like 3D gaming and HD video, but can also rely on a 1.2GHz quad-core processor for less intensive tasks, like text messaging and Twitter. This way, the Galaxy S4 can save on battery life while still having huge power when it's needed.

This compares favourably to the Galaxy S3, which has a 1.4GHz quad-core processor with 2GB of RAM (same as S4) and none of the fancy octa-core trickery of the S4.

Numbers aren't everything when it comes to smartphone processors though, and we're most interested in finding out if the S4 can save enough on battery power to see two full days of average use, something most smartphones - S3 included - struggle with.

Operating System

Samsung gained as many fans as it did critics with its TouchWiz Android skin and the 'created for humans, inspired by nature' theme for the S3 and all subsequent smartphones and tablets.

Once the annoying bleeps and bloops accompanying almost every tap are turned off I quite like TouchWiz, and including it with the S4 means that anyone who's used a Galaxy device in the last year will feel right at home.

That being said, consumers looking for a pure Android experience may want to look elsewhere, such as the excellently-priced LG Nexus 4, which we recently claimed to be the world's best smartphone.

Camera

When Samsung announced the Galaxy S3 we were slightly disappointed by its camera because, although an improvement over the S2, it shared the same 8-megapixel resolution.

Thankfully, Samsung has taken the game on this year and fitted a 13-megapixel camera to the Galaxy S4.

Visually, the S4's camera looks almost identical to that of the S3, save for the LED flash now located underneath it (when viewed in portrait) instead of the left side, as with the S3.

Samsung has also updated the Galaxy's front-facing camera from 1.2 to 2-megapixel, and it can now record full 1080p HD video.

The Galaxy S4 is definitely a case of evolution rather than revolution for Samsung, which means, although the South Korean has produced another excellent smartphone, customers may feel disappointed that the update isn't on the same scale as when the S3 replaced the S2 last year.

This could well be Samsung's 'iPhone 4S moment', where a lack of external change leads some to assume a lack of improvement overall, but there's no way of saying for sure until we get our hands on an S4 for a full review and set of comparisons soon.