OK short version.
Colour on film VS video.
HD, DVD and DV all compress the hell out of colour. In the PAL world they are 4:2:0 instead of 4:4:4 (in NTSC they are the same except DV which is 4:1:1, so if you take NTSC DV and make a DVD from it you end up with 4:1:0!!), *and* are only effectively a little less than 8bit colour (256 shades of Red Green and Blue).
To wrap one's head around this, do the following. Create a 720x480 image in photoshop. Let's say it is a pattern of 720 x 480 individually coloured pixels, with the first pixel being red, the next green, then next blue and then repeated.). If you looked at a black and white version of the image you created, you could see each individual pixel. If you looked at just the colour information you would also see each discrete pixel clearly.
Now convert that image to DV or DVD. In B&W you can still see each pixel clearly (mpeg2 compression notwithstanding) but suddenly there is not a pixel for each piece of colour information - there might be as little as one piece of colour information for every *four* pixels of black and shite information. If you looked at just the colour information it would look really blocky and low rez. (Studio cameras may be 4:4:4 or 4:2:2, but nothing in the consumer realm is.)
Now even if DVD etc. were 4:4:4, (i.e. keeping the colour and luminance informatio at the same resolution) film hold a lot more than 8bit colour can. To capture film properly you need at least 12bit colour, and many prefer to work in 16bit.
This is why CG effects that look great in the cinema often look hokey on DVD - a lot of the detailed colour information that fooled your brain into seeing the CG as real has been thrown away in the transfer to DVD.
As for exposure/latitude/dynamic range, the sensor in your video camera cannot handle the wide range that film can. So you either end up crushing the blacks or blowing out the whites.
This means that in a scene like the trash compactor you may lose a lot of the detail as that scen is dark, or that you end up with lost detail on the white stormtroopers armour. it is especially bad in scenes where you have a mixture of dark and light parts of the one image.
To get around this, you can make multiple captures - in layman's terms one dark capture, one middle of the range capture and one bright capture.
You can then merge them together intelligently into a single HDR file that keeps all of the information from the really dark detail to the fine lighter details.
Thankfully there is an open source way to store this, the openexr format. You can do more reading here. http://www.openexr.com/samples.html
Take a look at the stained glass image on that page , if doing a single pass to capture that from film, you would have to choose one of those three outcomes, by using HDR you can map it all down to keep the dark and light details, retaining as much information from the film as possible.
Below the left image is Paul Debevec's shot of a Stanford cathedral interior, by doing multiple exposures you can get all of the information and tone map it down to 8bit like the image on the right. It works the same for transferring film to video.
There are some more examples here http://www.hdrsoft.com/examples.html
and a nice introduction to HDR here.
http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm