2013 is still young but has been an interesting year so far in terms of mobile image capture. At the Consumer Electronics Show in Las Vegas and at the Mobile World Congress in Barcelona a number of devices, all of them running the Android operating system and boasting 13MP camera modules, were announced. This includes the Sony Xperia Z, the ZTE Grand S, Huawei Ascend D2 and Lenovo K900. In March Samsung followed with their new flagship device, the Galaxy S4.

While Samsung is betting on a 13MP horse, HTC, the second largest manufacturer of Android devices, is going the opposite way, equipping its HTC One top-end phone with an unusually low resolution 4MP sensor with large photosites (which HTC calls "ultrapixels") and optical image stabilization (OIS) which, in theory, should result in improved low light capabilities.

However, Google's Android OS is of course not your only option if you are currently in the market for a smartphone with good imaging capabilities. Apple's iPhone 5 and the Nokia Lumia 920 have been on the market for a while and successors are no doubt in the pipeline, but for now these devices are more than valid options for iOS and Windows Phone users, respectively.

Arguably the most interesting new Android devices, the Samsung Galaxy S4 and HTC One are finally available for purchase - and crucially at last in our office - so we put them head-to-head with the established competition from Apple and Nokia. Here is an overview of our competitors in this shootout and their key photographic specifications:

PhoneSensorApertureOptical IS Focal length*Aspect ratio
 Samsung Galaxy S4  13MP CMOS  F2.2  no  31mm  4:3
 HTC One  4MP CMOS  F2.0  yes  28mm  16:9
 Apple iPhone 5  8MP CMOS  F2.4  no  33mm  4:3
 Nokia Lumia 920  8MP CMOS  F2.0  yes  26mm  16:9

*35mm equivalent

For the purpose of this shootout we have taken sample images in a variety of "real-life" situations and in our controlled studio environment. This article comprises of four pages with the following content:

Landscape

This shot was taken in bright sunlight with all cameras in Auto ISO and White Balance modes. The phones were mounted on a tripod using an iStabilizer smartphone holder and all images where shot from the same position.

Samsung Galaxy S4, ISO 50
Apple iPhone 5, ISO 50
HTC One, ISO 107
Nokia Lumia 920, ISO 100

Looking at the four samples above there are some obvious differences in terms of contrast and saturation. The Samsung, HTC and Nokia all produce very saturated and contrasty images, with the Nokia almost going slightly over the top. The iPhone captures a more natural image, with less saturated colors and visibly lower contrast.

Samsung Galaxy S4, 100% crop
Apple iPhone 5, 100% crop
HTC One, 100% crop
Nokia Lumia 920, 100% crop

Looking at the 100% crops, the difference in pixel count between the cameras becomes very obvious. The HTC One looks the sharpest at a pixel-level but this is due to a combination of the low pixel count and pretty strong sharpening. However, with its 13MP sensor the Samsung, at least in good light, simply captures more detail.

All the cameras here struggle with low-contrast detail, even at low ISOs and in good light. This is very visible on all the trees and foliage in the scene. However, the Nokia's mix of heavy noise reduction and sharpening looks worse than the rest up close. The Apple and Samsung arguably offer the best balance between noise reduction and sharpening here. The S4's sharpening is still quite strong but in good light its 13MP CMOS captures the most detail in this comparison (by a whisker).

Portrait (Shade)

This outdoor portrait was shot hand-held in the shade, with consistent camera-subject distance. Again, all cameras were set to Auto ISO and White Balance and as you can below, the light was bright enough for all devices to select base ISO (or close to it in the case of the HTC One).

 Samsung Galaxy S4, ISO 50
Apple iPhone 5, ISO 50
HTC One, ISO 102
 Nokia Lumia 920, ISO 100

In these portraits we can see the same differences in saturation and contrast as in the landscape shot above, but there is also some exposure variance. The HTC has produced a darker image than the rest while the iPhone's image is the brightest. In this light situation Auto White Balance has produced a slightly blue cast on all images.

 Samsung Galaxy S4, 100% crop
Apple iPhone 5, 100% crop
HTC One, 100% crop
Nokia Lumia 920, 100% crop

Despite all devices keeping the sensitivity low in this low contrast situation, all images suffer from a loss of fine detail through noise reduction. The sharpening on both the Nokia and HTC is very strong, resulting in a punchy but slightly unnatural look. Again, the iPhone and Samsung show a better balance of noise reduction and sharpening, but ultimately the Samsung captures slightly more image information than the Apple device.

Portrait (Sunlight)

This is another portrait shot, taken hand-held in bright sunlight, to see how the cameras deal with skin tones in contrasty lighting conditions. Again, all cameras were set to Auto modes.

 Samsung Galaxy S4, ISO 50
Apple iPhone 5, ISO 50
HTC One, ISO 114
 Nokia Lumia 920, ISO 100

Again, the HTC captures a slightly darker image than the iPhone with the Samsung and Nokia falling in between, but overall exposure is within acceptable limits on all devices.

Samsung Galaxy S4, 100% crop
Apple iPhone 5, 100% crop
HTC One, 100% crop
Nokia Lumia 920, 100% crop

All cameras struggle with the bright highlights caused by the reflection of the sun on the subject's skin. On the Samsung, Apple and Nokia the red channel is clipping, resulting in blown out areas on the skin. The Apple iPhone is the worst offender here. The HTC One, on the other hand, is the only camera here to capture most of the highlight detail which indicates that its large photosites can capture an additional amount of highlight range over the higher resolution competition.