Is an interpolated frame tripping up the quality of LCD video?

[Rob J in WNY]

I have a Sony KDL-40XBR4 which I've owned for well over a year and a half. I've very much enjoyed this TV. It has a 120Hz refresh panel, and offers two modes for "frame interpolation" (Sony's "Motion Enhancer" in the menu).

There is also another control over video called "Cinemotion," which affects the manner of how pulldown is applied to various video sources. There are two modes for "Cinemotion" as well. The Cinemotion setting also determines how the Motion Enhancer will operate (interpolate).

My Blu-ray player is the Sony BDP-S350, connected to my TV via HDMI, passed through my Pioneer Elite SC-05 receiver. The TV does handle 24p.

Now, here is my question:

Does an "interpolated" frame have accurate image detail? More specifically, does it preserve, without compromise, the details of the surrounding frame as it "interpolates" the in-between point of motion? Although motion interpolation DOES smooth motion very nicely, the artifacts it also can produce on occasion can be a distraction, and affects picture quality at times. I've observed this on every brand of LCD with the function turned on in use with HD video (either Blu-ray 1080p or cable/satellite 720p/1080i sources).

I have found that, for Blu-ray viewing, turning the Motion Enhancer completely OFF, with a Cinemotion setting of Auto2 does a spectacular job of presenting the video. It looks truly genuine without the interpolated frames. I'm not sure if Auto2 provides the steadier 5:5 pulldown on 1080p source material, but the clarity of video appears to be better than without any of the motion enhancing "frames" added. I have to wonder if the interpolated frames are not derived accurately in all respects, not just the edges of motion as most noted being affected by the artifacts, and degrade the basic image quality as well. I would imagine that it would take a HEAVY amount of processing to create intermediate frames (even MULTIPLE intermediate frames) accurately to place in between native frames already running at 24 per second. When the Motion Enhancer is turned off, and Cinemotion set at Auto2, the image quality, even through motion, is strikingly better.

I have left it off for quite sometime now. I have all but forgotten the "novelty" of the smoother motion, which can be "smoothed" all the way into the "soap opera effect" at its maximum setting with my Sony XBR.

Anyone have any thoughts? Anyone also turn it completely? Anyone have anything to report on the actual quality of an interpolated frame? I would love to see an actual sample of an interpolated frame in comparison to a native frame. It would be interesting! Please feel free to discuss your thoughts!