For the price, the Sony EX640 puts in a good performance. While the Vizio M3D0KD is a better TV overall, the Sony delivers a tidy picture with better-than-average black levels. Color depth and saturation are excellent, even if some others are able to deliver more vivid tones. Shadow detail isn't as fine as on other TVs we compared, but the trade-off of an inkier background is worth some loss of fidelity in murkier areas. The TV also showed some issues in the uniformity department, where I detected some uneven backlighting and dirty-screen effect, but it wasn't terrible.
Click the image at right to see the picture settings used in the review and to read more about how this TV's picture controls worked during calibration.
|Comparison models (details)|
|Sony KDL-55HX750||55 inch, edge-lit LCD|
|Vizio M3D550KD||55-inch, edge-lit with local dimming|
|Sony KDL-55HX750||55-inch, edge-lit LCD|
|60-inch, edge-lit LCD|
|Sharp LC-60LE640U||60-inch, edge-lit LCD|
|Panasonic TC-P55ST50||65-inch plasma|
Black level: In bright scenes, it's hard to tell the difference between most well-set-up TVs, but give them a challenging dark scene like "Creation" (chapter 4) from "The Tree of Life," and differences leap to the eye. This scene is quite difficult for LCDs in particular because it involves colored wisps moving against a black background. The EX640 was no exception, showing lighter black levels than the Vizio and the ST50, but it outdid the Samsung ES6500 and the HX750 and looked very similar to the Sharp.
One strike against the Sony was its slightly less-than-perfect rendering of shadows. After the Romulan spaceship passes at the start of chapter 8 in "Star Trek," you see the antagonist, Nero, lying on a green surface. On the other TVs you could see more of the green pattern in Nero's shadow, but on the Sony EX640 it was a little smudged, though at least it was darker.
Color accuracy: While it's not possible to dial in color on a Sony to the extent you can on an LG or Samsung, the color reproduction of the EX640 was quite respectable. Whether it was the deep greens of the trees and baby nursery in "The Tree of Life" or the child's subtle blue jumpsuit, the colors of the Sony seemed more natural than most of its competitors', with the exception of skin tones, which looked a little bluer than on the other sets. The Samsung E6500 was better in terms of skin tone, with a much rosier, healthier-looking -- though still emotionally depressed -- Brad Pitt. Overall, I found that while it didn't show the most accurate color, the Sony was better than most in the more important area of color saturation.
Video processing: Sony has built itself a fine reputation on its video processing and the EX640 continues the company's good work. The TV was able to play back our 24p test scene from "I Am Legend" without any trace of judder, and it also passed our synthetic 1080i deinterlacing test as well.
As I'd expect from a 120Hz TV, the EX640 achieved around 600 lines of moving resolution. As usual to get it to do so meant activating one of itssettings, but I preferred to leave those off.
Uniformity: Perched between the Samsung ES6500 and the Sony HX750, the EX640 was the best of the three in terms of uniformity. The other two TVs had some real issues with backlight clouding and spotlighting in the corners, and while the EX640 was better, it wasn't immune to these problems. There was some spotlighting of the backlight, but it wasn't as noticeable as on the other two. If you want immunity from these problems, look to the Panasonic ST50 plasma or the Vizio M3D0KD with their gorgeous black screens.
One issue that the TV did exhibit was "dirty-screen effect," whereby the backlight structure was visible as darker vertical lines on gray or white screens. If you watch a lot of ice hockey, you might find this distracting.
Off-axis viewing of the EX640 showed a desaturation of color and an even greater blueness to blacks, but this is a common problem of LCDs -- especially at this price.
Bright lighting: Tradionally LCDs perform at their best when in a lit room, but the Sony did have some issues. In a lit room, a black scene looked off-blue in the corners, but the EX640 wasn't alone here: it was the same with the HX750 and Samsung 6500. If you want true black, then you need to go for the Vizio M3D. The Sony has a semimatte finish and wasn't particularly reflective -- about the same level as the other TVs.
|Geek Box: Test||Result||Score|
|Black luminance (0%)||0.0139||Average|
|Near-black x/y (5%)||0.2705/0.2679||Poor|
|Dark gray x/y (20%)||0.3141/0.3315||Good|
|Bright gray x/y (70%)||0.3125/0.327||Good|
|Before avg. color temp.||10034.9337||Poor|
|After avg. color temp.||6479.0542||Good|
|Red lum. error (de94_L)||2.9833||Average|
|Green lum. error (de94_L)||1.2529||Good|
|Blue lum. error (de94_L)||5.8093||Poor|
|Cyan hue x/y||0.2308/0.3366||Average|
|Magenta hue x/y||0.321/0.1439||Good|
|Yellow hue x/y||0.4322/0.4954||Poor|
|1080p/24 Cadence (IAL)||Pass||Good|
|1080i Deinterlacing (film)||Pass||Good|
|Motion resolution (max)||600||Average|
|Motion resolution (dejudder off)||320||Poor|
|PC input resolution (VGA)||1,920x1,080||Good|