In rec.photo.digital R R wrote:
What feautures separate a very expensive digital movie camera to a
relatively affordable one? The
price differences are significant and I assume there are several reasons for
it.

Typically, image quality and image size drive digital camera prices up the
most. Take a look at the reviews on http://www.dpreview.com and you can see
for yourself what differentiates expensive digital cameras from less expensive
models.