I know there is an awful lot of discussion on the sparkle issue in this thread, and mostly by prospective buyers (such as myself). I think the current owners would rather not worry about it seeing as they've already spent the money and it's not an issue to them. However this is a fairly big deal for us nitpickers and hopefully we can use the collective power of the forum, and especially the z4100 owners to prove/disprove theories about it.
Perhaps this deserves a separate thread, but the more owners we have to help diagnose the problem the better, and this thread gets a lot of traffic.
In my professional experience, leaving these things up to the manufacturer to fix will likely not yield any results as they likely don't see it as a problem because people will still buy the product without knowing of the problems (initially). But if we make a big enough stink about it, hopefully we'll catch the ear of some Sony management who can get the ball rolling on a fix, or at least make a statement about the issue.
I think there are three things we can do to help fix this issue:
1. Contact Sony and tell them about the issue. Here's a link to their technical support page
2. Try to determine possible causes or solutions (see below)
3. Try to quantify the issue so we can see if the issue diminishes over time or on different settings.
Now, I'm just thinking out loud here... someone mentioned earlier about seeing a sparkle at the beginning of the Planet Earth BD. I remember seeing that as well on a W4100 at a local store. It was when the earth was shown from space and there was a lot of black in the scene. I noticed a fairly large sparkle on the top, just right of center area in what appeared to be inside the black bars (not in the image portion of the display).
If this is repeatable, and if we can prove it by finding the exact minutes/seconds in the movie that the sparkle appears, then I would say it's more than likely a processing issue, which could hopefully be resolved with firmware updates. Of course finding more occurances will better prove the theory and could even help Sony figure out the problem.
If this does not appear to be repeatable or localized to specific media/signals/inputs/color modes/etc. and the phenomenon is perfectly random, then we know that it is likely not software/firmware related, but most likely a hardware/design flaw that would need to be fixed.
So, does anyone want to give that a shot? Who has Planet Earth on BD and can notice sparkles and note the minutes/seconds?
And for everyone who's noticed the sparkling problem, please contact Sony and tell them about it! Especially the owners!
Thanks for reading this far,