What website can tell me about a Sony Handycam CCD-TR81?

you can't get info because it is a very old camera. it definitely did not come out in 2005, the Hi8 system was already obsolete by then. it is more like a 1990 model. it does not come close to miniDV in any measure of quality. The "hi" in Hi8 means it is better than Video8, which is not saying much because Video8 was the lowest resolution analog video system ever made.