大夫，樓主師兄，
I just read an interesting comment made by AVforums UK.
Seems they have different views about the black level measurement.
There has always been a large dependence by some forum members and enthusiasts on cd/m2 black level figures within reviews and trying to compare these on forums, where the measuring equipment, method and surroundings have always made these types of measurements useless in any kind of comparable manner. The results really are based on certain factors that for us are never as repeatable or properly measurable to make them a useful tool for readers to use. You cannot take measurements we make here with a K-10 meter and then compare them to readings taken by say a Spyder III in a different country. There are just too many factors that make that approach bad practice in terms of imaging science and that’s before we take into account that doing these measurements on, say, an LCD that switches it’s backlight off at 0IRE, makes the measurements pointless. Mind you that hasn’t stopped a few from complaining about the lack of such measurements in our reviews and while we will start to mention our results, they will not be used for marking purposes or any other evaluation process. We do not recommend trying to compare black level readings with any other source, be that another review elsewhere or measures taken by forum members. The only real comparable difference you could take as being minimally accurate is by the same reviewer using the same equipment, method and conditions.
So, with that important disclaimer out of the way, the VT30 measured with our Klein K-10 in dark surroundings and calibrated mode we got 0.02 cd/m2 at 0IRE and 79.35 cd/m2 at 100IRE (approx. 3,967:1 on/off) using standard window patterns from our Sencore VP401. Our 8 month old VT20 measured 0.04 cd/m2 at 0IRE and 75.12 cd/m2 at 100IRE calibrated (1878:1 approx on/off). Our 2 year old Pioneer LX5090 Kuro measured 0.03 cd/m2 at 0IRE and 110.1 cd/m2 at 100IRE calibrated (3,670:1 approx). Ansi-contrast measurements on the Pioneer were 0.04 cd/m2 black and 85.4 cd/m2 white averaged results, with the VT30 managing 0.03 cd/m2 black and 72.4 cd/m2 white averaged results.
As we have said take what you will from those measurements for the three TVs we have set up here side by side and calibrated in the same room. Looking at those results there should be a big difference between the VT20 and VT30 by almost double the on/off contrast figures but in actual content viewing (watching the same Blu-ray clip on all three screens together at the same time), it is very difficult to put those numbers into definite visual differences with moving content. The VT30 is blacker than the VT20 by a small margin in real-life viewing (and in ideal conditions) with not a lot to separate the VT30 and LX5090, not just in terms of black level, but with general calibrated image quality. Some will ask why we haven’t pushed the brightness of the sets to higher levels (some claim 120 cd/m2 as a standard), but another important point that is always forgotten with calibrated results is that the image has to be easy on the eye for long term viewing and complimentary to the viewing room conditions. We have gone for what we determine the ideal viewing circumstances based on industry standards and as close to perfect as you can get on a consumer TV. This means a dimly lit viewing room with suitable placement of ambient lighting. These conditions won’t match some reader’s environments and we recommend that you take this in to account when making your purchasing decision.
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發表於 2011-6-1 00:20
樓主
PIONEER BDP-LX55 
