Samsung LN-T5281F LCD 1080p HDTV Measurements

Measurements

Resolution
With a 1080i HDMI input and the aspect ratio set to Just Scan, the sharpness test pattern was flawless, with a crisply-defined, 1-pixel width line. No edge enhancement was visible at any setting of the Sharpness control (the control position shown in "Settings" above was my first, pre-setup best estimate, and though moving it produced no visible change one way or another, I left it there). The luminance multiburst at the maximum 37.1MHz was also beyond criticism, and the color burst very nearly as good.

At 720p HDMI, in Just Scan, the results were nearly as good as with 1080i, with only a small rolloff visible in the maximum frequency luma and color burst. The results at both 480i and 480p were good for those formats.

The component results were a significant step down from HDMI. In 1080i, the luma resolution was gone by 37.1MHz. At 720p, the resolution was a bit better than that, though satisfactory. The 480i/p results were also satisfactory. HDMI is definitely the preferred connection for this set.

Color
In theWarm2 color temperature setting, the Samsung's pre-calibration color temperature was good but a little higher than the desired 6500K through much of the brightness range (Fig.1). Calibration brought this closer (Fig.2). It might be argued that both results are slightly compromised based on the numbers alone, but Figs.3 and 4 show that the color balance was significantly better after calibration. Out of the box (Fig.3), the set was minus red across the full brightness range with respect to the D6500 standard. Ideally, red, green, and blue should all overalap in a single horizontal line at the center of this chart. The larger, post-calibration result in Fig.4 shows a much better match.

Fig.1

Fig.2

Fig.3

Fig.4

The primary red and blue color points on the Samsung were exceptionally close to the correct values with the Color Space set to Auto (Fig.5). (The white triangle outlines the Samsung's color space, with the primaries at the peaks of the triangle; the black triangle encloses the standard REC 709 color space.)

Fig.5

Contrast and Overscan
Measuring the peak contrast ratio of the Samsung proved challenging. When set up so that the LED backlights shut off with a full screen, video black image, the light output was 0.00. With 0.00 in the denominator, you get an infinite peak contrast ratio. But that is not a reasonable result. To get any number at all, I used 0.001 as the black level (the lowest number that my Minolta light meter will read!). Using that technique, the peak contrast ratio measured 46,000:1 (46 foot-Lamberts peak white, 0.001fL video black)!

That isn't really a very meaningful figure. And while I don't know how Samsung arrived at its spec of 500,000:1 (!), the peak contrast ratio of this set is still very impressive, whatever the number.

The ANSI contrast ratio measurements produced a more realistic result. Using a 16 square checkerboard pattern of alternating white and black squares, I measured an impressive ANSI contrast ratio of 2,340:1 (38.84fl white, 0.0166fL black)

Overscan in both component and HDMI averaged under 0.5% in 720p and 1080i with the aspect ratio set to Just Scan, and between 3% and 3.5% in 480i/p. I suspect the 0.5% readings were the result of masking by the screen frame rather than a circuit design limitation.

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