The Gopro HD HERO2 is a very popular sports camera, revered for its exceptional video quality. The light weight, rugged body can take the abuse of extreme sports. It seems to be an almost perfect sports camera with the exception of one flaw. Take a Gopro underwater and you will have focus issues. Some describe it as a Best Underwater Cameras "slight loss of sharpness." Others say the image is blurry. The Gopro website has this to say about the problem, "Please note that due to the curved lens of the waterproof housing for the HD HERO camera and standard def Wide HERO cameras, you will notice a slight loss of sharpness with underwater images. We are developing a flat glass adapter/housing specifically for underwater use, thus allowing for the same image sharpness that you enjoy with your Gopro camera above water."

https://teachbesttech.org/best-underwater-cameras/