Usually we try to avoid motion blurring but
when used to the extreme (with long time exposure) the resulting pictures
are often great. Just have a look at the image below. It was exposed with
about 20 seconds so the cars on the highway transform to lines of light.
The "Bridalveil" effect is typically used
with waterfalls. It's finally nothing else than a simple long-time exposure
so you need a tripod here. The effect starts to get obvious with exposure
from 1/2 second and up. The surrounding environment remains the same while
the falling water produces stripes of bright light on the film. The longer
you expose the more enhanced is the Bridalveil. The optimal exposure time
is also dependent on the height of the waterfall but I would suggest about
4-8secs as a rough rule.
This effect is achieved by choosing a relatively
long exposure time and zooming just after the shutter is released. The
picture below shows a sort of coma effect because the zooming was finished
well before the shutter was closed. There numerous variations possible