The Nexus 5 is very different. It is the first device to come pre-loaded with the latest version of Android, now up to version 4.4 and called "Kit Kat". Most of the changes to the software are pretty significant, though the underlying structure and the way the operating system works hasn't changed too much.
Many new features are immediately visible on the Nexus 5's home screen. The biggest addition is the fact users can now swipe from left to right to immediately launch Google Now. There's also heavy integration with Google search (the Google search bar is permanently fixed to every available home screen), larger app icons, a translucent status bar, and white folder backgrounds. The default messaging app has also been replaced by Google Hangouts, which now handles SMS messages alongside regular hangout chats.
The Galaxy S4 has a 13-megapixel rear-facing camera, an upgrade from the Galaxy S III's 8-megapixel snapper. The most significant camera upgrades are all software related. 'Dual Shot' allows users to take a photo with the front and rear cameras simultaneously using selected templates, 'Drama Shot' takes 100 shots in four seconds and 'Cinema Photo' is similar to Nokia's Cinemagram feature picking one part of the photo to move while the others stay still -- somewhat like an animated GIF.
Overall, the camera on the Samsung Galaxy S4 is outstanding. In our experience, it's the best camera on any Android phone we've ever reviewed. When used on the standard "auto mode" it produces excellent photos with outstanding levels of detail and good colour.
The Nexus 5 has an 8-megapixel sensor with optical image stabilsation (OIS). It also introduces a new feature called HDR+, which uses a burst mode to take a number of photos and then stitch them together. The new mode aims to capture clear and sharp photos even with both dark and bright areas in the shot, such as light entering through a window, for example.
The results are mixed. While the Nexus 5 is certainly capable of capturing a quality photo, the camera's software is slower to focus than most of its competitors. This becomes an issue when trying to capture fast moving objects. In these cases, by the time the camera focuses and captures, the shot you want to capture is often lost.
For photos without any moving objects the Nexus 5 can certainly produce some impressive photos. It offers an excellent amount of detail, good colour reproduction and little image noise. Macro shots are the clear highlight: in almost every instance, we were able to capture an excellent close up shot with excellent colours and detail, and a blurred background.
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