Long exposure at Lake Balaton
One of the most interesting and fascinating photography techniques is the long exposure. Many are drawn to it as with its use we can create unusual images and scenes that are impossible to see with our own eyes.
A long exposure technique can help to simplify a scene by blurring water and making it smooth, same with the moving clouds. It can also help to remove people as long as they are moving and the exposure is long enough. A long exposure can emphasise the movement of water in a waterfall, a stream or fallen leaves in a river. My favourite effect is when the sky colours with the clouds are combined at sunrise or sunset. This usually creates a very interesting and painterly looking combination of colours and shapes.
Long exposures tend to work great when combining moving and non moving objects. In the photo above, the pier and the boats are static while everything else: the water and the clouds are moving and end up blurred by this long exposure.
The duration of a long exposure can be anything from 1/2 second to a few minutes. It all depends on the subject, how much movement there is in the scene and the desired effect.
This photo from Lake Balaton in Hungary was taken at sunrise just when the sun started rising and shining some golden light. There were some clouds on the horizon which made it easier to not overexpose. This was a 30 seconds exposure at f13.
When capturing a long exposure it is essential to have a good sturdy tripod to avoid any camera vibrations. It’s a good idea to also protect the camera and the tripod from strong wind and stay still around the camera while the exposure is being made.
To achieve long exposure times there are two ways: first is to reduce the aperture (high f number) e.g. f13, f16, f22. However going above f16 is not recommended because the quality of the image will be reduced. To increase the exposure time even more we can also use a Neutral Density (ND) filter. These filters are just like sunglasses for your lens, they darken the image and force the exposure to be longer.
The most common ND filters I use are ND with 3 stops or 6 stops, meaning that they can increase the exposure by doubling it three or six times. For example if your exposure without any filters is 1/2 second then with a 3 stop ND it will be 4 seconds and with 6 stops: 32s.
As for what ND filters to use, there are several brands on the market and most of them are very good. The ones I use are NiSi and Kase.