I found the same issues with the (3) different 650's that I had. The motion blur on slow pans especially. Keep in mind that noise on the grass of any sports is more likely due to the feed quality, or the cameras that are being used. Not all cameras in any given game are high def, so different angles may be using different cameras, that are not high def. Also, cable companies are trying to cram in so many high def channels that they are having to really compress them due to limited bandwith, and compression usually leads to loss of quality. I'm not saying this is the problem, but it's a definite possiblity. If you can ever find ANY Channel that just comes in perfect (aside from the blurring) than you know the tv is not the issue. Certain channels that claim to be high def, also commonly upconvert non high def content to 1080i or 720p, so any flaws will most likely be magnified.
I can't really address the black crush, and some of your other issues, but I did have a 750 after my 1st 2 650's, and although some blurring is inherent with lcd's, I found the 750 to not have the same quality issues of the 650. I found it to be a much better picture overall, and it seemed to handle SD progamming better as well. I just could not deal with the halo, so I tried the 650 for a third time and really found that with 3 different sets, and having the 750 for a month, that, to me, the 650 was lacking in some areas.
Bottom line is, if you are not happy with it, you should exchange it.
I purchased an LN52A650 a few weeks ago, and I have been seeing issues with the TV from the get go. Here is what I see:
1. Black Crush. I have tried to tune around this, but when I do it makes the overall picture way to bright and washed out looking.
2. Motion blur. I see this mostly when watching hi-def content, but I also see it in SD content as well. Usually, it is most prevalent when a scene is panned from one side of the room to another, or when arms are moved up and down very quickly. I dunno if this matters or not, but it also seems much more prevalent in darker scenes than brighter scenes.
3. When watching football, I see noise in the grass on the field. It looks like its cycling from clear to blurry. Its not so much of an issue when they are upclose, but when the cameras pan back from the filed and show a large portion of the field.
Here is what i have done to try and tune around this:
1. Tried the CNET optimal settings, this just made the picture way way to dark for our liking and the black crush was terrible. I ended up switching back to the "normal" settings, but none of this seemed to matter.
2. MOved the HDMI cables around betwene inputs to isolate bad cables( per samsung support), changed inputs from HDMI to component when that did not help, and there was no change on the above issues.
3. Upgraded to the latest firmware from the samsung website.
The cable box, DVD player, blue-ray player, etc all seem to show the same problem on different inputs and input types.
I called Samsung, and they blamed the cable box, the hdmi cables, the way the content was recorded, etc (basically said it couldn't be the TV casuing this issue). However, my last TV was a 55" rear projection (HD capable) and it had none of these issues. All using the same components (minus the blu-ray player).
I wonder if there is something wrong with the image processing on this TV(maybe just mine). My in-laws have an XBR it is way more fluid, but I think that the picture on this TV is much better when it seems to work. I want to keep the TV, but I don't think I can live with this and I am thinking of returning it. Does anyone else have these issues? I have 9 days left to return it, but dunno if I want to try another LN52A650 to see if this is an isolated problem with my TV or give a plasma a shot. Since this is my first LCD, I don;t know what to expect, is all this normal?