To slow down the shutter speed, switch the Nikon D3000 to manual exposure or shutter priority mode, and then use the command dial to adjust the shutter speed to a lower setting. Various automatic settings also have slower shutter speeds.Know More
Roll the exposure mode dial to the "S" for "Shutter Priority" or to the "M" for "Manual." "Shutter Priority" allows the user to set the shutter speed, but the camera selects the best F-stop for good exposure. "Manual" allows the user to set both the shutter speed and the F-stop.
Use the command dial on the Nikon camera to scroll through the available shutter speeds to the level that you want. The Nikon D3000 adjusts from 30 seconds to 1/4000 of a second, and both settings allow you to choose from the entire latitude.
Test the new shutter speed setting to ensure that the photo quality is what you want. Try testing it on objects that are moving as quickly as the target for the best effect. Keep in mind that shooting at lower speeds is harder to do in low light. However, Nikon displays a "Lo" warning when lighting is too low to make the shot.