you will also notice that peter and mikael change guitars depending on the song. this is partially due to tunings, or needing of re-tuning, or for specific instruments used for specific songs due to various preferences.
same goes for bass player. and some bands due this just to showcase what a wide guitar collection they have. Opeth arent one of those bands though. go see Rush if you want to see a lot of guitars.
i think all the songs in lamentations are in standard E tuning... it's just that some songs/parts suit a certain bass/guitar sound better than others.
the need for re-tuning may be right, too... from what i've heard from bootlegs, they tune between songs quite a bit; but it wouldn't have looked cool on the dvd
One of my friends performed a song starting off soloing with a distorted acoustic guitar. It didn't sound completely right, but I didn't realise he was playing an acoustic until he appeared, as he was behind the audience using a wireless receiver thing.
he only does in windowpane, right? great song, but i guess it would sound great without capo as well. i dislike them. every time i meet with other ppl i forgot my capo - and also it slightly detunes my guitar...
he also uses a capo on hope leaves, which is pointless, i know how to play the bass parts without a capo....that noob. Windowpane is an exception though, he follows the guitar a lot, so it would be hard to play it without one, but thats just the way he recorded it.