I used a GoPro HD. Originally I did a lot of shooting using the head mount, but you move your head too much
So I found this PERFECT setup called a RadPole - it's made by the guys at http://www.kayalu.com
- truly a perfect device for me because I use the RAM Tube rod holder for my central holder on the spine of the yak in front of me.
The RadPole is a perfect mount and comes setup for a light and/or camera insert at the top and fits onto a RAM 1.5" ball. It also has adapters to work on a Scotty mount that convert Scotty to a RAM ball. The Radpole itself goes from a 1.5" RAM ball up a composite shaft anywhere from 18-31" depending on the one you want. At the top the shaft has another RAM coupler which accomodates either their Kayaklu LED light or a camera mount with the screw etc.
The beauty of the RadPole (the pics are on their site) is that with the GoPro or any camera mounted on it you can easily articulate the camera position by leaving the upper ball joint somewhat loose, so you can point it in any direction quickly as needed. The only downside is that since the radpole is connected to the kayak body it really conducts hull slap sound to the camera, but most of my video will have music ultimately anyway.
I usually shoot with the GoPro HD at 720p (1080p is just too fat and 720p looks good enough) and the fisheye lens gives you a huge POV range compared to a traditional lens.
While I have toyed with various DIY solutions I found the Radpole to be supremely engineered and worth every penny. Now I need another GoPro and another camera mount to get some other views