Audio is another issue. While a DSLR is capable of recording good audio, the tiny microphone built into the camera has some serious short comings. First, because it's in the camera, it's very susceptible to all kinds of noise generated by simply using the camera. In addition, it's quality is dubious because of it's size and location. These shortcomings have spawned a plethora of aftermarket audio devices intended to be attached, mechanically and electrically, to a DSLR. Being the gearhead that I am and, also wanting to venture into the video end of things (I did lots of high end video years ago, with dedicated video gear, long before it became in vogue), I purchased some of these cool accessories. Among them are a Beachtek DXA-SLR Pro audio adapter, which allows me to connect high (broadcast) quality mics, wired and wireless to my DSLRs. This is a huge improvement over the built in mic and offers a good deal of flexibility and features like audio monitoring and mixing of two channels.
I could go on for a bit, but suffice it to say that learning the ins and outs of video with a DSLR will be a fun road, filled with errors to learn from. Last weekend, I shot some video of the annual Gilford Old Home Day Woodsmen's competition. This is really my first "serious" experiment with video, so don't be too harsh. It was shot with a Nikon D3s DSLR, the Beachtek audio adapter coupled to a shoe mounted Sennheiser microphone and I used my 80-200mm f/2.8 lens.
And, I've also been playing with a GoPro Hero3HD Black Edition action video/still camera. Really a cool device and I have a mount for it on the inside of my windshield. Coming back from a shoot last week, I recorded a couple of interesting clips: