Image size

We've shot our sample images at the maximum available image sizes on our test devices. However, those are not necessarily the image sizes you would use to share images on social networks or on the web in general. This is especially true for the 38MP images of the Nokia Lumia 1020. Part of the reason why the phone captures images with such high resolution is to improve the performance of the digital zoom and to reduce image noise by downsampling high-ISO images. Therefore you can configure the Nokia to only save a smaller 5MP version of your images or both a 5MP version along with the original 38MP file. 

The Sony Xperia Z1 follows a similar concept. The 20.7 MP maximum resolution is only available in the so-called manual mode which allows you to set some shooting parameters manually. Maximum ISO in this mode is 800. In Auto mode the file size is 8MP. Like on the Nokia, the surplus pixels are being used to facilitate a better quality digital zoom and average out noise through downsampling. Below we're showing some of the lower resolution samples next to the hi-res versions to give you an idea what image quality you can expect when shooting at 5 and 8MP respectively.

Sony Xperia Z1, 20.7MP, 100% crop
Sony Xperia Z1, 8MP, 100% crop
Nokia Lumia 1020, 38MP, 100% crop
Nokia Lumia 1020, 5MP, 100% crop
Sony Xperia Z1, 20.7MP, 100% crop
Sony Xperia Z1, 8MP, 100% crop
Nokia Lumia 1020, ISO 320, 38MP, 100% crop
Nokia Lumia 1020,ISO 320, 5MP, 100% crop

Conclusion

Looking at the samples on the previous pages it's fair to say image quality on smartphone cameras is getting better and better with every device generation. In our tests the Nokia Lumia 1020 arguably offers the best all-around image quality. It captures great detail in good light and its Xenon flash provides excellent performance in very dim light situations. There is a lot of luminance noise in its high-ISO output but chroma noise is well under control and the very large 38MP image files mean that at normal viewing and printing sizes noise becomes much less visible.

If you only want to share your pictures online you can also set the device to only save 5MP images and conserve space in the phone's internal memory.  Thanks to Nokia's clever downsampling algorithms the lower resolution images are comparatively clean even at higher ISOs and still show good detail. They might look a little oversharpened for some people's taste though.

The 1020 only struggled in our night shot. We took 30 shots with the Nokia but the shutter speed in such a dark environment was just too slow to get even a single 100% sharp image. In those situations we recommend upping the ISO manually in order to achieve a faster shutter speed. As we've already pointed out in our full review, the Nokia's performance can occasionally feel a little sluggish.

The Sony Xperia Z1 also offers very high resolution results, but suffers from noise and artifacts at all ISO settings. This is only really visible at large magnifications though and the Sony's good exposure and usually pleasant color response make it a good alternative for those who only share their pictures online at smaller resolutions. Another advantage of the Sony is that thanks to its responsiveness and dedicated shutter button, in terms of operations it comes as close to a compact camera as a smartphone can get.

The LG G2's image quality is not quite on the same level as the Nokia's and Sony's. Its efficient optical image stabilization helps keep things very steady in low light but very strong noise reduction is applied at all ISO levels and its auto white balance tends to capture slightly cool colors. Like the Sony, its LED flash cannot compete with the much more powerful units on the Nokia and Samsung. There's nothing wrong with the LG's camera but its image quality is simply not up there with the best of the 2013 smartphone generation.

Despite its 1/2.3 sensor the Samsung Galaxy S4 Zoom doesn't capture any more detail than the current generation of smartphones. In fact, the lens of our test unit appeared to be slightly soft at its wide angle setting. However, the Samsung is worth a look for those mobile photographer who want a powerful flash and an optical zoom.

Arguably most users would not choose their smartphone based on the camera alone. Nevertheless those who want a decent camera in their mobile device have more choice than ever. In terms of image quality smartphones are quickly catching up with traditional compact cameras and we're already looking forward to seeing what the smartphone cameras in our next shootouts and reviews will be capable of.