PM sent, let us know how it goes.
Hi PnP,
I received your raw file. It is a Canon 5DII raw file shot art ISO 12800, but it is an sRAW1 file, not a full res raw file. There is some funkiness that goes into the sRAW files, including, obviously, changing the pixel dimensions of the resulting file. This also tends to change the nature of the noise in the file - it is "chunkier" than full res file noise. Here is a comparison of raw, sRAW1 and sRAW2 for the Canon 5DII from imaging-resource.com:
https://www.imaging-resource.com/PRODS/E5D2/E5D2SRAW.HTMI downloaded the three raw file types shot by them at ISO 12800 and took a look at the noise and then processed the raw and the sRAW1 file in AI Clear. The full res file contains the white speckly, wormy artifact, whereas the sRAW1 files does not, but there is noticeable lower frequency blotchiness in the sRAW1 file due to the chunkier noise in the original file. See attached images - the first image is a comparison of the noise in the raw and sRAW1 files - this is a screenshot of the two images in PS, with the zoom level of the two files matched so that the image features are roughly the same size. The second image is the result of applying AI Clear, using the default settings.
Both images were converted in Raw Photo Processor, which does no noise reduction or sharpening. The "Blur Chroma" option was disabled. The raw file was converted using VCDMF interpolation; the sRAW1 file is already interpolated in-camera. Both were converted to 16bit TIFF, sRGB.
The fact that your sample image did not show the high-frequency speckly, wormy artifact in the shadow areas is likely the result of the sRAW1 file used as input. Interpolation and reduction in pixel dimensions combined the high-frequency noise into a different, lower-frequency (chunkier) form that appears as blotches instead of speckles.
Also attached is the overall test scene that imaging-resource uses for all of its camera sample images. The area of interest is highlighted with a yellow box.
I have found that if you use the full res image treated with AI Clear and hit it with a couple of passes of the Despeckle filter in PS, and then use some gentle deconvolution to recover the original sharpness of the image, you get a decent result.
kirk