Sony A7S High ISO NR
Sony A7S High ISO Noise Reduction
The Sony A7S offers only three High ISO Noise Reduction settings: "Off", "Low" and "Normal" (default). The user manual doesn't say at what sensitivity High ISO Noise Reduction begins to be applied, so we've included crops from ISO 50 on up to find out.
See for yourself how the the default and lowest noise reduction settings compare to RAW files with no noise reduction or sharpening applied. Click on any of the crops below to see the corresponding full-sized image.
As you can see, the Sony A7S's default High ISO Noise Reduction already has a noticeable effect at sensitivities as low as ISO 50, and the "Off" setting really isn't off (which is almost always the case), as the A7S still applies fairly strong noise reduction with that setting at high ISOs.
Note that unlike the A7 and A7R, the Sony A7S's high ISO noise reduction does not suffer from the issue of blurring our red-leaf fabric more at the Off setting than the Normal setting at moderate to moderately high ISOs.