- Written by John E. Johnson, Jr.
- Published on 21 December 2009
On the Bench
Following are graphs for the Color Temperature, RGB Levels, and Gamma for the VF55 before calibration. Notice particularly that the gamma was very high, and the low IRE levels were crushed (too dark).
The VF55 has color controls for each of the primary colors at the high end of the IRE scale as well as the low end.
Following calibration, I obtained the graphs shown below. You can see that I was able to flatten the RGB levels, and I think the wildly fluctuating levels at IRE 10 simply represents data beyond the sensor's ability to detect. In older HDTVs, even when the computer is sending a signal of IRE 10 to the display, light leakage brings the total amount of light to a level within the sensor's ability to detect, so you can get some form of measurement.
I was also able to lower the gamma to a more acceptable figure, and I am sure that a professional calibrator would easily be able to do an even better job, since IRE 0 really is IRE 0, with no light at all coming from the panel.
The measured contrast ratio after calibration was 296,105:1 when IRE 100 was 30 foot-Lamberts. The spec sheet for this HDTV states a CR of 2,000,00:1. However, even the ~ 300,000:1 CR that we measured is probably just residual electrical noise in the sensor when the signal to the TV was IRE 0. I really don't think any calibration sensors out there are able to detect this kind of CR when the IRE 100 reading is 30 foot-Lamberts. Perhaps a very specialized laboratory sensor that is custom-made could do it, but not the standard professional test packages that TV calibration services have on hand. IRE 0 should have resulted in all the LEDs turned completely off, so the CR is theoretically infinite.
The smooth motion technology worked beautifully, with only an occasional glitch when the distance between a fast moving object in one frame vs. the next frame was too much for the TV to interpolate the additional frame. It took getting used to, because movies looked like live TV, but after awhile, it is enjoyable, because motion is so smooth, and it seems more involving. I felt closer to the action.