Pioneer lined up its newest plasma display next to top-of-line TVs from Panasonic, Samsung, Sony and Sharp today. An interesting experiment, for sure. And it got everyone in the room talking about the same thing: contrast ratios. You can see why just by looking at the image above, which shows three plasma screens with power on but no image (the Pioneer is on the lower right, the Samsung HP-T5064 is on top and the Panasonic PZ700U is on the left). None of the screens were calibrated, which would make a difference. But the reason Pioneer's screen looks so much darker has to do with a lot more than calibration, or contrast ratio.