Slow shutter speed photography is an art, a classic and easy technique of how to utilize your DSLR camera with creativity. Even though these pictures can be taken by a Digital camera if there is an option of controlling the shutter speed. However a DSLR Camera has always the option to control shutter speed.
The technique behind this type of photography is very simple. First let me tell you about a normal photo, in normal photography, once you press the button to take picture, it takes a split second and two sounds normally come in to hearing; click click, one is for shutter open, other for shutter close. These two sounds have so less time between them that you think mostly its a single sound. However if you go to a shutter mode in camera and then select shutter speed to be lets say 10 seconds, you will see these sounds will be 10 seconds apart; click 10 seconds click. The camera will capture everything happening in those 10 seconds and merge them into a single picture, that’s why you will see light trails on roads and water falls like a smoke/cloud effect.
For this type of photography your camera should be on a tripod or placed somewhere and you should take picture with either a shutter release cable/wireless or with timer, so that the camera doesn’t move when you take a picture.
This is ideal mode, when you are capturing waterfalls, roads at night, night photography and fireworks. Many people use creativity with an LED light as well. If you select shutter speed to lets say 30 seconds and move a light in a patters, like LED on sides of a Car, you will see the end result; an image of car with light stripes on its corners.