Pentax K-x High ISO Image Quality
The Pentax K-x offers four high-ISO noise-reduction settings, allowing you quite a bit of flexibility in choosing how you want to make the trade-off between subject detail and noise levels. Settings available are "Off ", "Low", "Medium" (default), and "High". Like the Pentax K-7, the K-x has unusually flexible noise reduction options, letting you program at what ISO High ISO Noise Reduction starts, in addition to the levels. Options are ISO 400, 800, 1600 and 3200. The default is ISO 800, which is what we used.
See for yourself how the noise reduction works under daylight lighting. Click on any of the crops below to see the corresponding full-sized image.
The above crops show the effects of the four levels of High ISO Noise Reduction available on the Pentax K-x. The default setting is "Medium", but to our eyes it's a bit strong (except at ISO 800, where it seems to be weak - firmware bug?), so we're glad Pentax included "Low" and "Off" settings. Note that while our Pentax K-x Operating manual says that noise reduction is performed at ISOs above the start ISO, it is clear from the ISO 800 crops that noise reduction is applied at the start ISO. Also note that some noise reduction is always performed at ISO 6,400 and above, even with the Off setting.