@WXM:
Same settings in all images. But yeah, I see where you’re getting at. Those settings aren’t quite there yet, still just an experiment I did.
The BluRay is bad in that sense that it has far too much grain and actually heavy artefacting in some of the effect shots, because the CGI/VFX stuff had been done in 480p (SD-quality) and was never rendered in HD. So for the BluRay-release they upscaled those. Also, the live-action scenes were filmed with HD-ready equipment, but not native HD.
This was the case for both seasons 1 and 2.
Season 3 was sort of a transition (HD-ready being used for the effects as well) and the live action had better quality.
Only season 4 was shot in native HD.

It’s a shame that Trek-sources always have quality-issues.