Digital SLR sensors usually attract dust after a few months of usage. This article describes the options available for cleaning the sensor and their effectiveness.
Blowing
This method is useful to remove small dust particles that are not stuck to the sensor surface. It involves blowing on the sensor with a small handheld blower. Although this might reduce the dust to some extent, the method is not always effective. It can simply relocate or redistribute the dust on sensor or even introduce new dust particles. It is ineffective against dust particles that have moisture, or ones that are glued to sensor surface.
Using a Brush
There are commercially available sensor cleaning brushes to clean the surface. These brushes can be used to wipe the sensor surface to get rid of the dust. Since this is a contact based method, it is more effective in removing stubborn dust compared to blowing. Visible Dust and Coppehill manufacture sensor brushes. Photographic Solutions manufacture a brush - Brushoff - which also serves as antistatic, making dust removal more effective.
Liquid Based Cleaning Systems
This method uses easily evaporating liquids along with special swabs to clean the sensor surface. This involves wetting the swab and wiping the sensor surface with it. Being liquid based, this is the most effective solution for removing stubborn dust that would be glued to the sensor surface. But the fluids used, such as Eclipse Fluid and methanol, are usually inflammable and are not permitted in flights. Hence they can't be carried with you when you are travelling. Copperhill makes swab based cleaning systems.
Precautions for cleaning sensor
Whatever method you use, it involves keeping the shutter open and accessing the chamber where the sensor is located. It is important to be careful during the process, or you may end up damaging some sensitive parts of the camera. Ensure that you start the process with full battery. In case the battery drains in the middle of cleaning process, the shutter may attempt to close and get obstructed by your cleaning system. This could permanently damage the shutter and render your camera useless. If you are not confident of cleaning the sensor at home, it is always wise to take it to a service center.
Detecting digital SLR camera sensor dust and how to clean the image sensor
Dark spots on the image, created by dust on the camera sensor is a major problem with DSLR cameras. This article series is about detecting sensor dust, preventing accumulation, and cleaning the image sensor.