The thing is that I really don't get the latter.

Dynamic range means the range of different luminosity levels the sensor (or film or some other media) can show, without black or white clipping, right? In other words, you could have dynamic range of, say, 1/1000, meaning that the sensor can show 1000 different levels of luminosity without clipping. So, if you have two pictures, one with DR of 1/1000 and another with 1/10 000, the latter will look a lot "smoother", because the brightness steps are smaller by a factor of ten.

So what's the tonal range, then? As far as I can tell, it means basically the same thing, because, again, it defines how fine the gradation of color luminosity is.

Can anyone help me to get some sleep once again? :D

There's a discussion on the subject here (http://flickr.com/groups/hdr/discuss/72157594586681094/) - I don't even want to think about summarising it :)

Thanks for the link, mugley!

So let me get this straight: A picture that has even only to levels of luminosity can have a huge DR, as long as those two brightness levels are very far from each other in the spectrum, and not clipped?

And the tonal range is what defines the number of steps of luminosity, such as 1/1000?

Did I got that correct?