SJCAM SJ7 Star

If the GoPro Hero5 Black is the current undisputed heavyweight champion of the 4K action camera world, the scores of cheaper rivals that are currently coming through the ranks are the young and feisty contenders for its crown.But so far none of them has managed to topple GoPro's relatively expensive offering, even if cheaper rivals claim to boast similar spec-for-spec attributes, proven sensors and comparable technology.Cameras from Yi Technology (notably the YI 4K Action Camera), Olfi and Veho