This is a completely manual lens. This means you need to set the focus before using it every time. Its also a lot heavier than most general use skydiving lens are. I looked at one for a while and passed. I had a Canon 14mm briefly and it was on a 60D but it was WAY too heavy for me to jump on a regular basis and I sold it (Lazlo bought it and turned out GREAT photos on it).
If you are fine going manual and don't mind a lot of weight on your head look at it.