Samsung UN65JS8500 4K LED TV Review
With great contrast, color, and HDR capability in tow, this one's worth howlin' about.
As a member of Samsung's SUHD line, we had high expectations for the Samsung UN65JS8500, the company's upper-tier, flat 4K with quantum dots and edge-dimming software. Naturally, it doesn't perform to the standards of the flagship JS9500, but it's also a lot more affordable.
Overall, the JS8500 is a terrific performer, though it suffers from similar kinds of drawbacks inherent to very flat, edge-lit LED TVs. The screen's backlight uniformity leaves a bit to be desired due to all of the light eminating from the vertical edges of the screen, and likewise this makes for somewhat limited dimming, as well as a narrow viewing cone.
Make no mistake, however, the JS8500 is still one of the better edge-lit 4K options you can buy, and flourishes in brighter rooms, delivering a ton of color and brightness.
Calibrating the UN65JS8500 was a very familiar process, and because the TV is quite accurate out of the box in Movie mode, also quite quick. We calibrate each TV for two reasons: to ascertain the efficacy of the calibration controls, and to get the best idea of how its performance compares to dark-room/home theater calibration standards.
To that end, I used the TV's backlight control, gamma slider, and 2/10 point white balance controls to set a reference brightness of about 40 fL (or about 140 cd/m2 ) and a dark room 2.4 gamma curve. Fortunately, the TV's natural RGB balance and grayscale production was so accurate that calibrating to these standards was a quick and relatively painless process.
Below, you'll find Samsung's defaults in the Movie mode preset (left) alongside my final calibration settings (right).
For an edge-lit LED TV, the JS8500 actually boasts very good contrast. Using the standard ANSI checkerboard pattern (6x6), I measured a black level of 0.05 cd/m2 and a reference brightness of 168.50 cd/m2 , giving the JS8500 a static contrast ratio of 3,370:1. This is quite good, though the TV is neither as dark nor as bright as Samsung's flagship JS9500—but that's to be expected, considering the backlight and dimming technology present.
Viewing angle is one area where the JS8500 underperforms a bit, especially compared with the huge viewing angles you'll find on plasma, OLED, and LCD sets using IPS style LCD panels. I measured a total viewing angle of 34°, or ±17° from the center to either side of the screen. This is a little lower than the average edge-lit LED (compared to both the JS9000 and Sony X850C UHD TVs).
Many TVs adhere to a standard 2.2 gamma out of the box, but Samsung has confided in the past that they aim for a slightly more dim-room friendly 2.3 curve, which the JS8500 follows quite naturally, though it tested with a 2.28 sum. Moving the gamma slider from the "0" default to "-1" pushed gamma down from 2.28 to 2.4 after calibration, making for good luminance allocation for a very dim or dark viewing environment.
Grayscale & RGB Balance
TVs produce grayscale elements (neutral tones, like gray/white) by combining red, green, and blue colored sub-pixels—this is called "additive color." The aim for current HDTVs is to produce grayscale tones that adhere to a specific spot on the CIE color space chart, specifically D65. The exact location is that x = 0.313, y = 0.329, with a correlated color temperature of 6500K (6504K, most specifically).
When grayscale elements exhibit visible error, this is measured in a collective/max sum called deltaE (or dE), where a dE of 3 or less is considered ideal (no visible error, though some technical error is acceptable). Out of the box, the JS8500 tested with a grayscale dE of 3.15—just barely over the ideal limit, which is a great result. After calibration, the adjustments I made reduced the error further, down to 2.16, within ideal limits.
The before/after RGB emphasis (x/y considered, Y not considered) reveal that most of the reduced error is from a reduction of the backlight, as the general RGB emphasis is almost identical. This is often the case with edge-lit LED TVs, where the edge diodes are driven a little too high in default settings for ideal dark room performance.
A color gamut is a visual illustration of a display's hue and saturation for its primary colors (red/green/blue), secondary colors (cyan/magenta/yellow) and gray/white point. While the standard color gamut model does not display step luminance for the produced colors (which would require a three-dimensional space), the luminance allocation can be roughly figured the gamma and RGB balance charts.
Compared to the standard rec.709 color gamut (which is used by everything except Wide Color Gamut/Adobe RGB content), the JS8500 is very accurate, you could even call it spot on. Each of the primary and secondary colors are within visible error ranges, so much that almost no adjustments were made during the calibration process.
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