Generally this blog's been aimed at beginners, but I found this Google TechTalk series on photography on YouTube and I had to share it. It's definitely advanced stuff, talking about exactly how lenses work, how a digital camera sensor works down to the atomic level at times. There's also some stuff on printing, HDR, and other topics as well (even one about eyesight).
There are 26 videos in all, each about an hour long, so if you watch all of them (like I've been doing), it'll take you awhile. Some presenters are good, others are quite boring, but all-in-all I've found it very interesting and I thought I'd share. I even rolled them into a playlist for you so you don' t have to hunt through them to watch them in order like I did ;-).