Photographic technique: photograph with the times long

To begin we need to have a clear idea of what we want from a picture with long exposition, for this I mean from 1’’, even if in some cases you can have wonderful results with even less time, for example, a landscape with flowing water.
It is very important to consider the instruments you use, in this case you may need a trestle proportional to your camera (if you use a reflex with a tele, you