DxOMark Mobile, who we regularly collaborate with to share their in-depth scientific testing of smartphones as part of our comprehensive product reviews, have recently put the GoPro HERO3 Black Edition through their thorough laboratory exercises — and drawn some interesting comparisons between the sturdy action cam and Apple's flagship iPhone 5.
The Hero3 finished with an overall score of 70, ranking at number 7 on DxOMark's list of mobile cameras. It came in just two points below the Apple iPhone 4S, which was for a long time the most popular camera on Flickr, having only recently been outpaced by the newer iPhone 5. DxOMark Mobile experts analyze 14 aspects of mobile imaging including detailed image quality assessment, flash performance, autofocus reliability and more to produce a final score of the mobile devices it examines.
One of the most interesting aspects of DxOMark's assessment of the Hero3 was their comparison between the video performance of the action cam and that of the iPhone 5. Whereas both are commonly used for capturing video footage, the Hero3 came in on top.
DxOMark awarded the Hero3 a video score of 75, whereas Apple’s iPhone 5 scores 70, despite the fact that the smartphone has the advantage of autofocus and image stabilization. However, DxOMark also points out that the Hero3 is a specialized product focused only on one task as opposed to all the functions the smartphone fulfills. Rugged cases with lens accessories like the Hitcase can help make iPhones more like an action cam, but DxOMark put the Hero3 and iPhone 5 toe-to-toe without the aid of an accessories.
The Hero3 also sports a 12MP sensor compared to the iPhone 5's 8MP sensor, which is also bound to be a factor in the testing results, nonetheless, some of DxOMark's report focuses primarily on the lens and we found the observations worth sharing here.
They found the Hero3's extremely wide angle (170 degree) lens offers it significant advantages over the typical 70 degree smartphone camera lens. DxOMark concluded such a super wide angle lens makes some specifications easier to achieve, and some much more difficult.
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.
You can see more of DxOMark's comparison of the video performance of the Hero3 and the iPhone 5 on their website, along with their full review of the Hero3.