How many megapixels do our eyes have?

BBC Focus Magazine has a regular Q&A section, which, unfortunately, they do not publish on the Internet. The March 2007 edition has a reader's question - "How many megapixels do our eyes have?"

Their answer approaches the question from multiple angles. I won't quote the entire response here, but some of the interesting "factoids" are:

• comparing the number of sensing elements - the eye has 5 million cones (the color receptors) and 100 million rods (the monochrome contrast receptors) which give a human the equivalent of two 105MP (MegaPixel) video cameras (because we have two eyes).
• comparing spatial resolution over the eye's field of view - we have the equivalent of 576MP.

(Source: BBC Focus Magazine)