I just got an e-mail from Brian with a long reply to the above comparison between ID and ACR/LR, and the go ahead to post it here. Like Vladimirovich, Brian prefers to have it posted directly, split up in several posts, and so be it. Below however a zip in addition for those who prefer that.
Kind regards - Hening.
From: Iridient Digital Tech Support <firstname.lastname@example.org
Date: 13. March 2013 20:37:03 GMT+01:00
[Comparing Iridient Developer and ACR/LR] part 1 of 3
I have no idea what Adobe really does in their software and how various versions of ACR/Lightroom may or may not match up with what they do in the DNG SDK. My quick tests with ACR version 6.7 and the Adobe 2010 process selected under the Camera Calibration tab seemed to show similar behavior with the DNG SDK and the "Blacks" slider adjustment found there, but I haven't done a real thorough investigation yet...
I read the notes on Shadows Fine Tune. Based on my quick tests this should be working as expected under the following circumstances.
1) When using "DNG Camera Profile..." options in Input Profile menu AND when the "Use embedded..." checkbox is checked on the Camera Curve pane the Shadows Fine Tune Slider will adjust the DNG SDKs exposure curves "shadows" variable which adjusts the contrast of the dark shadows region.
Where SFT = shadow fine tune control
Setting SFT to +100 in Iridient Developer will pass a value of 0 to the DNG SDK and lightens the dark shadows region compared to larger values.
Setting SFT to 0 in Iridient Developer will pass a value of 5 (the default used by DNG SDK v1.4 which also just happens to match up with the default "Blacks" slider available in ACR 6.7 when using the Adobe 2010 process under Camera Calibration pane. Not sure about other versions of ACR or Lightroom. Lightroom anyway seems to act differently when choosing the 2010 process and doesn't completely switch its controls at least not in my very brief investigation so far... the result here should be slightly darker shadows.
Setting SFT to -100 will pass a value of 20 and again this should go even darker with the shadow tones.
Old versions of ACR/Lightroom had a "Blacks" slider with a range of 0-100 and a default value of 5. This OLD control seems to act much like the "Shadows" variable available with the exposure curves in the DNG SDK v1.4. This is based on VERY quick visual tests of a couple images.