Getting back to the magic trick of a Dynamic iris, the ON number is very impressive in the real world of peak white and black contrast ratios! This test implies nearly a doubling in contrast ratio yet this is not the perceptual experience you will have.
All an iris can change is the light output to the imager, not the native dynamic range of the technology. What really puts this in perspective is switching the iris on and off with paused images. With the right image you can see a difference in light output yet with most the difference is quite subtle. Ultimately the biggest difference you see with this test is a change of the gamma response within the image rather than simple light output.
If the end user does not know what the image should look like, no references, they likely will not detect that it is wrong either hence the acceptance and popularity in the mass market.No matter what, it will never provide an accurate image due to the artifacts of an incorrect gamma response. The first two gamma plots of a window and full field pattern represent the calibrated response with iris turned off as the light output changes from 0-100 IRE in 10 IRE steps. The dotted line presents the desired response curve so please ignore the average gamma calculation.