I highly recommend the bophoto lens hood
 

Like the HD1 itself the lens hood seems much smaller in real life than one imagines looking at the photos below.

The 3mm aircraft grade plywood item is very light yet very robust and once it easily, securely clicks on the camera the effect is obvious. The image is much more well behaved! Not surprising, considering it hasn't got illegitimate light hitting it from 180 degrees anymore.

As Bo claims: "a hood is essential to controlling lens flare and, in the process of removing stray light from the lens element, it also increases the contrast in the image."

Definitely an oversight by Sanyo.

It also looks very, very cool.

http://www.bophoto.com/HDV

Watch out for termites, and roving bands of beavers ;)

Ha ha - I'll keep watch.