So what makes a good underwater camera? In addition to image and video quality, there are several other important factors to consider, like the overall quality of the camera's optics, including zoom range and maximum aperture. The latter is crucial for low-light photography, as larger aperture typically results in better photos since it allows more light in. It also minimizes motion blur, making larger apertures perfect for action shots. (Note: The smaller the number, the larger the aperture.)
What are the best GoPro accessories?