HDR FAQ:I am getting noisy tone mapping results. Is there a way to avoid this?
HDRI Tutorial:The Tone Mapping method “Details Enhancer” enhances local details a lot. If the local details of your HDR image are noisy (you can easily see that in the HDR viewer), then the noise will be enhanced as well, unfortunately.
If you have generated the HDR image directly from RAW files, then the noise may be avoided by converting your RAW files to TIFFs or JPEGs in your favorite RAW converter first. Then, process the converted files in Photomatix.
If you still get noise when using JPEG or TIFF as source files, then you will have to apply a noise removal tool to the source images.
If your scene is motionless (i.e. without moving objects), you should still be able to avoid having to use noise removal tools if you follow the two rules given below:
Rule 1: Set a low ISO setting (ISO 100 or lower)
Rule 2: Overexpose sufficiently, ensuring that the lightest image of your exposure sequence has its shadows in the mid-tones.
If you are using Photomatix with a single RAW image instead of differently exposed photos, then the chance of getting noisy results is higher, unfortunately. In this case, you should expose for the shadows by slightly overexposing your shot.
Photomatix also offers Exposure Fusion. Combining your photos with the Exposure Fusion methods is an effective way of reducing noise. The resulting combined image will show less noise that the individual source images taken under different exposures. We recommend in particular the “Adjust” fusion method.