The camera has a DxOMark mobile video score of 75, whereas Apple's iPhone 5 scores 70, despite the fact that the smartphone has both autofocus and image stabilization.
The comparison with a smartphone is especially appropriate when you look at the way that smartphones are commonly being used now to capture video footage of events, and manufacturers are beginning to make accessories to feed this market, such as rugged housings with wide lenses built in. The GoPro HERO3 has a massive advantage here in that it does not have to fulfill all the other functions that a smartphone needs to. This specialization allows it to be much more focused on its principal task without the need for compromise.
The key to understanding the GoPro results is the extremely wide angle of its lens (170°) compared to that of a typical smartphone camera (70°).This wide angle is very important for an action camera that can be helmet-mounted. It may record an entire event before the user can look at the video. However, it makes some specifications easier to achieve, and some much more difficult, which explains some of the differences between the GoPro and the smartphone cameras we have tested:
Specifications which are helped by a wide angle:
Autofocus: the ultra-wide angle gives a fantastic "natural" autofocus with its very large depth of field; no need to adjust the lens to get sharp images between 30cm and infinity.
Stabilization: a measured amount of vibration will produce much smaller motion-blur in the image of a wider-field camera, achieving better results without stabilization than certain smartphone cameras.
Specifications which are much more challenging with a wide angle:
Distortion: it would be impossible to design a reasonably-sized lens with a 170° field of view without distortion.
Lateral chromatic aberration increases with field angle, so it would be very difficult to optically control on such a wide angle lens.
Exposure: the wider field usually means more sky, so the dynamic range in the scene is likely to be higher.
Flash: uniform and powerful flash illumination on such a wide angle would be a real challenge, way beyond the performance capacity of a typical mobile device camera flash.
There were two additional low scores recorded for things unrelated to the large depth of field:
Lack of color saturation
White balance yellow bias in photo
http://www.dxomark.com/index.php/Mobiles/GoPro-HERO3-Black-Edition-Super-Hero/GoPro-HERO3-versus-iPhone-5
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