What is this? Why am I seeing it?

I've noticed something a tad odd in my video footage recently. If you look at my shots, the parts that are light tend to create funny looking rings. The colors then get darker as you look farther from the center.


Look at the color of the sky next to the skier, then at the color of the sky near the edges.



More funky circles....



and another skier with a godlike glow.

Does anyone know why this happens? Has anyone had the same funny effect themselves? If it matters, I'm using a t2i and an old nikon 24mm lens.

Thanks