I posted the below in another 71 series thread and was asked to post it here as well...
I got to calibrate two Samsung 71 series LCD flat panels today; the LN-T5271F and the LN-T4671. I must say that I am really impressed with these after calibration and that they totally blew away my preconceived expectations. I really didn't think these sets would perform all that great, but boy was I wrong.Test Equipment Used:
PhotoResearch PR-650 Spectroradiometer
Sencore VP-403 Calibration Generator
ColorFacts 7.0 Pro Software SuitEvaluation Material Viewed:
Comcast HD cable
-Harry Potter (OOTP)
When I first saw the image on the LN-T4671F I was not impressed and I was a little doubtful that the set would calibrated out all that well, but I went ahead and started working...
The first thing I did was take pre-calibration readings of greyscale, gamma, black level, white level, and chromacity (color gamut). Once I was finished with that, I popped into the service menu and was quite happy to see that the parameters are almost identical to the LN-Txx81F service menu. At this point my expectations started to increase as I have had great results on the 81’s (LINK)
Here is the precalibration gamma response. As you can observe, the precal gamma does not follow the correct curve nor does it meet the industry standard of falling between 2.2 - 2.5. The out of box gamma will result in a washed out image that lacks depth and realism.
To begin the calibration, I roughly dialed in black and white level and then established a baseline gamma. It seems that the 71's really like to sit at a gamma of around 2.5, but that they will play nice anywhere between about 2.2 ~ 2.55.
I had heard that the 71 series Samsungs could not run a natural gamma response. So I was pleased to see that I was able to get an exquisite and natural gamma out of both units.
Next I proceeded to dial in saturation and chromacity. In all honesty, the color gamut wasn't really all that bad out of box and this can be observed in the first gamut plot. Phase (tint) for magenta, cyan, and yellow was off a little. With the state of manufacturers not adhering to the Rec 709 gamut and blatantly abusing it, I was rather pleased to see that none of the colors were well outside the gamut boundaries. However, after calibration, I was very happy to see that I was able to get the colors even better. Magenta, cyan, and yellow came out nearly perfectly and all with only a minor sacrifice to the position of blue.
Furthermore, color gamut is only one aspect that needs attention with respect to color. The luminance (brightness) of the colors also needs to be properly adjusted and not all displays have this ability. Below are two tables of color luminance; one is at 100% output and the other is at 80% output. In each table the "W" denotes the actual luminance of white in foot lamberts. The left column is the calculated ideal luminance with respect to the actual white luminance. The second column is the measured luminance for each color as seen by my PR
I have heard mentioned that the 71 series Samsung's are not capable of accurately displaying proper luminance for all colors. As can be observed this is not correct. The tables above are from the LN-T4671F, but both units performed similarly well. The data gathered shows that these sets do have excellent color luma response when compared to the ideal luma level.
Furthermore, I took readings at both 100% output and at 80% output to test for linearity in color with respect to brightness. The measurements prove that these sets do have linear saturation with respect to output so the amount of color does not change with brightness. It should also be noted that the color gamut did not change with respect to luma levels either… GREAT
After color, I moved to greyscale and the results can be seen below.
As is common these days, the LN-T4671F was extremely cool (blue) out of the box with an average color temperature of over 11,000 K. After calibration however, the greyscale came right into line with an average temp of right around 6,500 K, just where it should be.
And above are the results for delta "E" before and after calibration. DE is essentially a more precise way to measure error (RMS error), and in this case error to grey tracking.
As can be observed, before calibration the DE was running around 45 across the entire luminance range. DE of 10 or less is considered ideal for a digital display so obviously 45 is way too high. But after calibration the DE came out really well averaging less than 3 at all luminance levels. You may observe that at 10 IRE the DE was measured at 38.5, but the window looked grey to me and there was a little ambient light in the room. At 10 IRE it can be difficult to get a good reading with any ambient light because 10 IRE is just so dim. Therefore, the DE reading for 10 IRE should be taken with a grain of salt
because it probably isn't accurate anyway.
And finally for greyscale here are the plots for color tracking. As can be seen, out of box there was so much blue that it was off the chart. There was also not enough red in the grey. After calibration all three colors combined brilliantly to make D65 grey.
I went back and touched up grayscale, black level, white level, gamma, and color and found that there was some interactions between settings. This was pretty easy to take care of with just one more calibration iteration.
Finally we got to view some material. Both the LN-T5271F and the LN-T4671 looked pretty much the same, but I calibrated the 46” unit for a dark room environment and the 52” unit to a mixed ambient light environment. I did more watching on the 46”.
BluRay and HD cable looked phenomenal. Colors were realistic and very accurate looking. Black level was decent and acceptable though I’ve seen better. 480p DVD through component looked great too. I thought the display's scaling was really quite good for an internal scaler. I also didn’t see any deinterlacing errors when watching 1080i through Comcast cable. I did not watch any 480i as the cable box on hand could only output one resolution and was set to 1080i.
The dark scenes in Harry Potter OOTP were quite nice even in a dark room (ambient light can help hid glowing black levels). I always wish black level were better on most digital displays so… Colors, detail, and sharpness were also great in Casino Royal and Harry Potter.
Comparing the 71 series Samsungs to the 81 series… I think the 81’s have better black level and slightly better color. However, the 71’s have slightly better gamma and better grey tracking. Honestly, I’d be thrilled with either unit and the differences between the two are not great. For my money I’d choose the 71 series over the 81 because the 71’s cost less and both designs are capable of similarly excellent image quality.
If you have any questions feel free to email [email protected]
Please note, it is a well established fact that coping service menu values from any given unit into another will not provide an improved image. Every unit needs its own calibration so getting my service menu values and putting them into your service menu will not help your TV's picture and will probably hurt it. Therefore, any emails asking for service menu values will be deleted and not read.