Finally a thread I know quite a bit about
I'm a video enthusiast and take a lot of videos and pictures and have edited them over the years for home videos shared with family
I am familar with the GoPro. I don't own one, but I do own the Contour which is basically the equivalent competition. I think the Contour offers a better form factor as well, but I wouldn't recommend that unless you want it for something where your hands can't be free. Skiing and snowmobiling are what I've used mine for. Sky diving
, bike riding and stuff like that are other great uses since you can't have your hands free. Diving
or snorkeling I find not so much as it is really helpful to have a viewfinder.
In regards to using a DSLR for video - I wouldn't recommend this either. The reason we have so many choices, is because each device is really good at one thing and ok at the others. I've seen some great video from DSLR's, but usually it is on very stable ground (i.e. not on a boat) or with a tri-pod.
So, what I can highly recommend (and I was a Sony camcorder owner nearly 10 years before going Hi-Def) is a Canon HD video camera. The current
model series that I'd recommend is the M5X Series. I'd probably go with the M50 myself if I was buying
today (I have the M30 and love it). The difference between the 3 models is the built in memory and the M50 has built in, plus an SD card. You can take stills with it and they do come out decent, so I always record
video to the SD Card and stills to the built in memory.
Another big plus is that Canon makes its own under water
housing. It's nearly half the price
of any 3rd party options. In the end, you'll still spend $1000, but that alone is the cost of many of the 3rd party underwater housings alone.
I have the housing for my M30 and love it. The camera also has an underwater mode which helps correct the colors. Take a look at some videos I've taken in the past. You can see when I am close to the surface it gets red and that's due to the color correction. If its really bright, it isn't really needed. I often just correct after the fact when its like that. The camera also has very good stability options so even on a moving boat or walking around, its not hard to keep it steady.
See some videos here maytrix007's channel - YouTube
While I think they look decent, they really aren't done justice until you watch them on a 1080P TV.
I've had my M30 2 years. I'll probably look to upgrade next year perhaps just because the optics do improve. The M50 has a larger sensor so it does well in lower light.
Hope this helps, you really can't go wrong with this camera.
EDIT - I should also add - one of the benefits to the built in memory and card is that since you likely won't take a ton of pictures, you'll never fill the internal memory and with the card, you can swap it out as needed. In a week long trip in the carribean, I might swap a 32GB card once. And today, you can use a 64GB card. I'm not a fan of the hard drives as I think the cards are faster and more reliably.