We shoot a specially designed chart in carefully controlled conditions and the resulting images are analysed using the DXO Analyzer software.
A high signal to noise ratio (SNR) indicates a cleaner, better quality image.
JPEG images from the Canon PowerShot S100 have a good signal to noise ratio, beating those produced by the Nikon Coolpix P7100, Olympus XZ-1 and the Canon PowerShot G12. This graph shows that even at the top end of the sensitivity range noise is kept under control.
This chart indicates that the Canon PowerShot S100's JPEGs compare well against the Nikon Coolpix P7100, Olympus XZ-1 and Canon PowerShot G12 at the lowest and highest sensitivity settings. However, it isn't quite so good between ISO 200 and 800. The graph illustrates a similar jump in dynamic range at around ISO 800 to the Canon PowerShot G12 which shares the same sensor.
For more more details on how to interpret our test data, check out our full explanation of our noise and dynamic range tests.