Nikon 300mm f/4 AF-S?

I'm doing photo journalism and wondering if this lens is good for taking candid photos of people hanging out at the beach? Or is the focal length too close (I have a DX body). I want to be able to get them from head to toe.

Added (1). Yeah I don't want to be far from them to achieve candids. But I don't want to be like two football fields away or the framing would be difficult.

Added (2). OOPS I men I want to be far not don't urghhh.

Sure you can.

It is also a great lens for shooting sports

To shoot from head to toe, you will have to stand off quite a bit.

Here is a shot the sort of fits the head to toe criteria. I was about 30 m from the action

Well you do have to stay away quite a distance. Remember that on a DX body you will have the field of view of a 450mm lens. But you don't wanna be too close anyway when shooting candids of people… Especially when it's a big lens like that. It can freak some people out. You wanna remain unnoticed. You can check out Nikons lens simulator to get an idea:

http://imaging.nikon.com/...simulator/

For people in general, a 35mm would be best. Photojournalists prefer a wide angle lens. That would be around 18mm to 24mm for your camera. If you already have the 18-55mm kit lens, that should be enough. The 300mm is for sleuthing (spy, paparazzi, etc.) but if that is what you had in mind in the first place then so be it.