Noise, Resolution and Sensitivity
Canon’s claims about the low level of noise from the new 12.1-million-pixel sensor are accurate, with the camera performing well up to ISO 400. Very slight image noise is visible, but it is easily dealt with by the in-camera noise-reduction.
As expected, there is an increase in noise as the sensitivity increases, but the S100 handles it well and keeps it to a minimum. Sensitivities up to ISO 800 are still usable, with ISO 3200 and 6400 being relatively noise free, although there is a loss of detail in JPEG files.
Generally, I found the default noise-reduction feature a little too harsh, but interestingly for a compact camera, the level of noise reduction can be reduced.
There is obviously far more control over image noise and sharpness when shooting raw images. Photos shot at the lower ISO 80-200 sensitivities can have quite a lot of sharpening applied to reveal small details, and virtually all colour noise can be removed. I tended just to take the edge off luminance noise, preferring a slight speckling to a smudged appearance and loss of detail.
Resolution, Noise & Dynamic Range: These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using the zoom lens set to a 50mm equivalent. We show the section of the resolution chart where the camera starts to fail to reproduce the lines separately. The higher the number visible in these images, the better the camera’s detail resolution at the specified sensitivity setting.
