ISO Speed Question...

[starlipermom]

 My DD is going on a Field Trip to some local Caverns.  I've been trying to decide which ISO speed I should use and also, should I use a flash or not (they may not even let you use a flash, I don' t know).

I'll probably be taking the Digital ONLY...

If anyone has experience with this, please share. 

Thanks,

[MOM2SNOX]

 My neighbor recently returned from Arizona and now has about a dozen pictures of bats on his wall.  I tried calling him to see what spped he used but he's not home.  Found this article from a caving magazine with some interesting information about shooting inside a cave! Hope it helps!