USE LONG EXPOSURES
By using very long exposure times, you can achieve virtually grain-free images
Much like using a 10+ stop neutral density filter in the daytime, blocking out the majority of the light getting through to the camera’s sensor, working at night means that you can utilise very long exposures. In turn, you can create star trails, smooth out the motion of the sea, or ‘paint’ elements into the scene using creative lighting techniques.
It’s difficult to know exactly what settings to use straight away, but there are ways around this. By using 30s exposures at very high ISOs, you can quickly gauge light levels, then work your way backwards. A 30s exposure at 6400 ISO would equate to a oneminute exposure at 3200 ISO. Stepping backwards, doubling the exposure time and halving the sensitivity each time means that, if you have the time, you could get a similar image at 100 ISO with a 32-minute exposure.
For these longer exposures, you will most likely need to invest in a remote timer, which will fire a signal to open the shutter when the camera is in Bulb (B) mode. Without this remote timer, you are likely to be restricted to a maximum of 30 seconds of exposure time, but this varies from camera to camera. Some have a function where the mirror can be locked up until the shutter button is pressed again.
Many cameras will have a long exposure noise reduction (LENR) mode. As the exposure time builds up, the camera’s digital sensor chip heats up and generates noise, or hot pixels. By turning on LENR, once the camera has exposed the shot, it will shut the mirror and exposure for an amount of time equal to the previous exposure, in order to build up a ‘map’ of the hot pixels. It then merges the two images together, averaging out the hot pixels.
There are two ways of creating star trails. You can commit yourself to one very long exposure, risking something going wrong during that time (the tripod falling over, someone walking through your shot shining a torch at the camera, and so forth), or capture a series of shorter exposures and combine them with editing afterwards.
“You will most likely need to invest in a remote timer”