long exposures

[danir]

I've noticed that many of the posted pictures here are taken with long exposures even when the light isn't that low. I know that long exposures mean closed aperture and more depth of field, but I wondered - is there any other reason to use long exposures?

 

[Torus34]

One is to blur motion. Converting headlight/taillight images into streaks, eg.

 

[Alex_B]

or to get that special impression when taking shots of moving water ....
... or ultra long exposures to get rid of people and cars in images (e.g. when you shoot architecture / cityscapes )