To maintain a standard across our review units, we calibrated the BRAVIA EX520 with Datacolor's Spyder3TV Home Theater Color Calibration kit prior to our visual tests. This is to ensure we assess the HDTV based on optimal display settings, and not purely on visual estimation alone. Using the TV's Standard preset, we've also disabled all the necessary boosters such as color and edge enhancement features. After calibration, optimized values were as recorded as:- Brightness at 50, Contrast at 96, Color at 54 and Tint at 0. Since our Spyder kit does not allow us to calibrate the TV's backlights, we've set the EX520's backlight to 5, or its neutral value. Black and white luminance yielded 0.112 and 249.686 cd/m2 respectively. While the calibrated results were satisfactory without any semblance of inconsistencies, rival models such as Panasonic's D25S or Philips' PFL6605D were noted to yield better contrast levels based on our previous tests.
DisplayMate is an application which generates a sequence of test patterns to determine the capabilities of imaging devices, like color and gray-scale accuracies for example. For our tests, we've hooked up the BRAVIA EX520 to our display test-bed PC using an HDMI connection. To be fair across the board, we have also disabled all visual enhancements on the TV in order to reduce the variables involved. Here are some findings based on the relevant and critical test patterns:-
We assessed the BRAVIA's screen uniformity using a white, gray, and red test pattern. While the display was fairly even on the white pattern, subtle changes in tint were discerned on a gray screen, and especially so around the corners. Also, a patchy and uneven texture was evident on a dark red pattern compared to the rest, no thanks to its edge-lit lighting.
Dark Gray Scale
Corresponding gray blocks showed good consistency with little tint variations. Blacks were nicely retained although a brightness level of "62" is required to discern the darker gray boxes. To add, black level performance worsened when the viewing angle was varied, a niggling problem which seems to plague most edge-lit LED sets.
Despite the minor kinks gathered from the Uniformity tests, Sony's EX520 managed to excel in the Color Scales evaluation with progressive scales and healthy color accuracies validated on the 10 principal colors.
256-Intensity Level Color Ramp
Similar to results derived from the Color Scales test, the BRAVIA performed splendidly on the Color Ramp pattern, given its linear gradients and almost compression-free conclusion. As such, displaying photographic images on the EX520 would be pretty much ideal. On the down side, darker tints can be subjected to contrast shifts at wider viewing angles.
IDT's HQV Tests are designed to assess image quality of digital displays through a variety of video signal processing tasks which includes decoding, de-interlacing, motion correction, noise reduction and film cadence detection. We've programmed the Blu-ray player to playback in 1080i in order to stress the TV's video processor. This compels the TV's processor to convert interlaced signals into progressive to accommodate the HDTV's panel. Here are the results we noted on a few of the more crucial tests:-
Digital Noise Filtering
The EX520 comes with three noise filters - a general noise filter, plus MPEG and Dot Noise options (the latter two are more for up-converted SD sources). Given the test disc's HD nature, it was the TV's fundamental noise filter which worked best in combating mosquito noise grains. Details were well preserved without sacrificing too much on image quality. It's apparent Sony has improved on their noise reduction capabilities since the NX810 we've last reviewed.
Diagonal Filter Test
Most modern tellies have little trouble with de-interlacing processes, and the EX520 reiterates that point yet again in the Diagonal Filter Test. With the rotating bar showing clean and solid lines throughout, we have little reason to doubt the BRAVIA's reconstruction techniques from an interlaced source.
Film Resolution Loss Test
Unfortunately, the EX520 either lacks cadence detection or poor inverse telecine conversion properties despite Sony's True Cinema claim. Either way, the SMPTE boxed pattern continued to strobe, with and without the Cinema Drive feature enabled. You might want to take note of this shortfall if you happen to prefer native 24p playback, an encoding found on most Blu-ray discs.