Originally Posted by *Mori*
Thank you for your offer. What we disagree is not the native contrast (on /off ) but what the dynamic dimming does. You say that it does very little (about 30%, right ?) and I say it is far more than that (rather 300%). It is clear to me that this discrepancy is mainly due to the methodology applied (how to measure that figure) and potentially to some degree about the proper equipment.
In order to quantify this properly you must prevent the laser from going off. In order to do that you must provide basically a black picture with just a tiny white square. Then you measure the black part with dynamic dimming on or off, respetively. To do that reliably you need a sensitive and suitable meter which is ideally in a tube so that you measure no light coming from the white area.
That's NOT how you accurately measure the peak ON/OFF contrast. You should be using a test pattern that comprises a singular white pixel in one of the corners against full field black. This prevents light engine shutoff. NOT a "white square"
. That's what I (and other AV professionals who know what they are doing) use. You can typically simply blank/mask off the singular white pixel such that it does not contaminate the measurements or prevent the ability to accurately measure what is the luminance of the black. You are creating a problem that should not exist, and by as a result of this making use of a "tube" there exists the potential for inaccuracy due to failing to capture 100% of what is the luminance of the black. So you are very likely ending up with an inaccurate black level reading as a result, hence the discrepancy as compared with everyone else who is going about things in the correct manner.
I use the most accurate method.
All of my measurements are taken within a fully 100% blacked out laboratory environment.
The equipment that I use includes:
• Konica Minolta T-10A Illuminance Meter
• Colorimetry Research CR-300 0.8nm Optical Resolution Spectroradiometer
• Klein K10-A Tristimulus Colorimeter
These are amongst the most accurate meters in the world.
All meters are sent back to the respective factories to be recalibrated annually and certified accordingly.
In short, there is absolutely nothing wrong with my measuring methods, nor my equipment. But thank you for the implication. Somewhat ironic when it's clearly the other way around...
The peak ON/OFF contrast performance with dynamic dimming set to FULL and with the projector properly and accurately calibrated including the white balance to D65 white point measures peak circa 23,000:1
I am by no means only person reporting such measurements. I know of at least 5 other AV professionals who concur, including
who is a very well respected AV professional reviewer for the likes of Sound & Vision magazine.
So, you claim to be measuring 60,000 - 70,000:1 ON/OFF contrast are you? My challenge stands. So, am I flying to visit you or are you coming to visit me. Either way I will have the £1,000 cash ready and waiting