On my first shot of London's monstrous Shard building, the S4 Zoom displayed a more even overall exposure than the S4. At full screen though, I found that the detail on the windows of the Shard weren't particularly crisp on the Zoom and there was quite a bit of image noise visible in the darker parts of the blue sky -- something not as noticeable on the S4's image.
Image noise crept into the skies behind the Queen Victoria memorial in front of Buckingham Palace. Both the S4 and the Zoom suffered somewhat from noise here, although both cameras did a good job at exposing for the scene.
Getting up close with the subject is where the Zoom really plays its trump card though. There's really no competition between the Zoom's optical zooming against the S4's digital crop zoom. The S4 Zoom is able to maintain full image quality when zoomed in, giving some room to digitally crop further.
The image quality might not be hugely impressive compared to dedicated cameras, but the ability to zoom like this will no doubt be a huge draw to enthusiastic nature photographers among you.
It did quite well in low light too. The Zoom's effort in my low-light scene was not only brighter, but suffered less from image noise. It also has a xenon, rather than LED flash. It wasn't quite as bright as the S4's but it was less harsh, giving a more natural ambience to the dark scene.
It can shoot video in 1080p, and you're able to use the full length of the zoom while recording. As previously mentioned though, it can be fiddly and does make a racket that the camera will pick up. Video quality was generally quite good. Certainly comparable to the S4, but with the bonus of being able to sneak closer to your subject.
The S4 Zoom as a phone
The S4 Zoom is running Android 4.2.2 Jelly Bean, of Google's mobile operating system. The interface is basically the same that you'll find on any of the other phones in the S4 range. There are multiple homescreens to fill up with apps and widgets, while other apps are kept in a separate app list.
Some features from the S4, such as S Health, aren't here, nor is the ability to show two apps on screen at once -- the screen is probably a little too small for this. Even with fewer added features, there's still a whole heap of bundled bits which can be confusing. There are multiple app stores, email clients and web browsers, while the settings menu is so vast it's had to be split into four categories. If you're new to the world of Android, it'll take some getting used to.
The 4.3-inch screen has a disappointing 960x540-pixel resolution, for a density of 256 pixels per inch. That's a major step down from the 440ppi Full HD display found on the S4 and particularly irritating given the phone's imaging focus, where more pixels will help show off a clearer image. It's sharp enough to keep fine text looking clear though, so don't expect a fuzzy display.
It's quite bright, and has satisfyingly deep black levels and rich colours. It might not have the pixel density to square up to its bigger brothers, but it will at least make your photos look lovely and colourful.
There's 8GB of internal storage as standard, of which 5GB is available for use. That's not going to last long once you start snapping away at full resolution, so you'll need to make use of the microSD card slot. You can set all photos and videos to save to the card and, thanks to a software update from Samsung, you're able to install some apps to the card too.
Processor and performance
Stuffed inside the body is a 1.5GHz dual-core processor -- again, a precipitous downgrade from the monstrous quad-core brute (octo-core in some places) in the true S4. Perhaps unsurprisingly, it didn't perform well in my benchmark tests.
It achieved 1,176 in the Geekbench test. By comparison, the similarly specced Galaxy S4 Mini did better at 1,875, while the standard S4 racked up a blistering 3,087. Similarly, on the Quadrant test, the Zoom achieved 4,420, putting it alongside older phones such as the HTC One X.
It's a real shame that Samsung hasn't packed in more potent hardware, as editing high-resolution snaps can be quite demanding of the mediocre processor. Editing photos in Snapseed was doable, but I've certainly had a more snappy experience on other, more powerful phones.
It was just about able to cope with playing Grand Theft Auto: Vice City, although the gameplay often became quite stuttery -- something of a problem when you're trying to hightail it away from pursuing police. The even more demanding N.O.V.A 3 was too much to even load properly.
It does have enough power for the everyday essentials, though. Navigating around the Android interface was fairly responsive and you won't notice its lack of power when posting updates to Twitter or Facebook.
With a chunky 2,330mAh battery stuffed inside, the S4 Zoom should be able to keep going for a decent amount of time away from a plug. Indeed, I found it to be pretty long-lasting when using it primarily as a phone. If you're fairly cautious, you shouldn't struggle to eke out a day of use.
As with all phones though, actual times will depend entirely on how you use it. Taking lots of photos with the flash on and zooming in and out will quickly deplete your precious power. Spend the morning snapping away and you'll almost certainly need to top it up at lunchtime.
If you want to maximise your shooting time away from the power, keep screen brightness turned down, avoid streaming music over 3G and turn off Bluetooth. Even so, if you're heading out to a bar after a full day of use, you'd be wise to keep an external battery pack such as the Mophie Juice Pack Duo if you want power for Spotify on your way home.
With its massive sensor, impressive megapixel count and 10x optical zoom, the Galaxy S4 Zoom may seem like the shutterbug's phone of choice. It's certainly the only phone to opt for right now if you value zooming in on things above anything else, although its image quality in general isn't significantly better than other high-end smart phones.
Its significantly increased size over the standard Galaxy S4, together with its pared-down specs, means it's definitely not a good choice for an everyday phone.