Originally Posted by mark haflich
On off contrast is just one of many factors and I really think its specious to state that is the only type of cotrast that makes a difference.
To clarify, I am speaking in terms of the numbers the Manufacturers give us to compare, not actual resulting intrascene contrast.
Sorry, I don't mean to sound argumentative, just clarfiying...
Some people forget that how well the IRIS works in real world viewing on a projector isn't related to the dynamic contrast that these MFR's claim, but its more related to the way it was programmed in how it senses the amount of light being output by a particular scene and the contrast of that scene.
If you have a projector capable of 5000:1 native, and say you were displaying a very bright scene in the sun, then you went to immediately an all black space scene, even if the IRIS truely closed down to create the effect of 100,000:1 very quickly, well under normal fL conditions (12-16), the white peaks / stars would suddenly look way too dim to our eyes. At some point the three types of measured / predictive contrast (Native, ANSI, and dynamic) do predict a MAXIMUM type scenario of what the capabilities are, and a low Native Contrast will directly conflict with a higher dynamic contrast in the sense that a projector with a lower Native Contrast cannot keep the white levels high enough in the resulting intrascene contrast. So while the dynamic contrast from the IRIS shifts the overall brightness of the image lower, the Native fails to keep the white levels at the proper intensity because the IRIS is reducing the total light output.
What I mean is, even if a projector were truely capable of some ridiculously high dynamic contrast and it could do it quickly, then it wouldn't matter if the native were low, there is a theoretical conflicting limit between the two numbers.
Now if you went from an already dark scene to an even DARKER scene, then you couldn't acheive that kind of contrast from an IRIS anyhow.
I'm not saying dynamic contrast itself is worthless, just that the numbers they give us are. It is a cheat measurement, 1 to 3 seconds might be a reasonable maximum to check maybe over scene transitions, but they leave it running for too long.
Also the garbage in/garbage out rule applies, some camera men don't give us enough contrast in a scene to even matter.
Regarding the IRIS issue, I am just saying that most IRIS's I have calibrated are not optimal at their maximum settings or most hardcore positions, it makes things like the stars look gray on some scenes when the IRIS closes down too much. I agree that the IRIS thing is subjective at least to a point.
Sorry, I seem to be extra wordy today, just can't spit out short sentences, I'll work on it