Runco LS-5 DLP Projector Review
Dear Gary:
Terry Paullin's glowing review (in Widescreen Review's Issue 149) of the Runco LS-5 DLP Projector really interested me.
I don't know Terry Paullin and don't want to trash him personally, but based on what he wrote about contrast ratio in a review of a Sony projector it is clear to me that he is pretty clueless about contrast ratio and the relevance of on/off contrast ratio and ANSI contrast ratio. I think it is really sad to see how far Widescreen Review has fallen. This is the publication that had what was likely the first good explanation of the relevance of on/off contrast ratio in a print publication explained by Bill Cushman in, I believe, his Sony HS10 review. This was where he explained that in order to maintain 100:1 intranet-image contrast ratio in images down to 10 percent video level on black it takes about 30,000:1 on/off contrast ratio with normal gamma.
Then the publication led the way with Greg Rogers explaining how higher on/off contrast ratio can support a higher gamma number and help images other than just those that people think of as being dominated by on/off contrast ratio (you basically can use more of the total range for the mid stuff instead of having to use it at the low end in order to maintain enough intranet-image in images like those 10 percent on black ones).
Now it seems they have devolved to what I consider the old and ignorant positions about ANSI mattering more than on/off contrast ratio because we have real rooms, when the reality is that in general it is easier to make a real room maintain the on/off contrast ratio of the projector than the ANSI contrast ratio of the projector (since it is generally easier to kill other light sources than reflections).
I don't think there is any way that Greg Rogers would have approved of some of the statements I saw from Terry in at least one article. Sorry for the rant, but I think it is sad for a publication to go so far backward in their comprehension of an important matter related to their subject matter, and I won't put much stock in what Terry Paullin says until he shows that he understands this subject matter and isn't making some of the same ignorant statements that have been shown to be wrong from others before. If Terry gets to read this and thinks I am wrong, then he is welcome to come here and discuss it (or just ask Greg Rogers, as it probably wouldn't take long for Greg to straighten him out). And I'll even apologize for being short, partially from tiring of fighting this ignorance on this subject matter from some people who are supposed to be experts in this field and don't even get some of the simpler physics.
All that said, as far as the projector is concerned, from what I have seen and owned (Planar 8150 and JVC RS20 for a couple), I would take a JVC RS40 over an LS-5 even if price wasn't taken into consideration. Not sure how much of a premium I would be willing to pay for the RS40, but it would be worth more to me. Fortunately, it doesn't look like I would have to pay a premium for the RS40 between those two choices.
Darin, AV Science Forum
Contributing Editor Terry Paullin Comments:
While you stated "you didn?t want to trash me," it seems you did a pretty good job of it without having any additional facts. I have (just) read a few of your posts and it is clear you have a good understanding of the subject. It's a shame you felt the need to launch an attack without at least contacting me to allow me to better explain my position (or to get more ammunition). My e-mail address has been at the bottom of my column for more than nine years now. You should also know that for nearly as many years I have taught Imaging Science classes for the ISF, AVAD, ADI, Panasonic, and most recently calibration software provider, SpectraCal. I have consulted to the industry on the topic of Imaging Science for many companies including Pioneer, Panasonic, DVDO, Optima, Dolby Labs, and others under non-disclosure.
I promise you I am not "clueless" about contrast ratio. Also, at a different time in my life, I ran a Standards Lab for General Radio (now GENRAD), where I gained a full appreciation for the notions of accuracy, repeatability, and potential measurement errors, which, as you?ll see, play a part in my aversion to some contrast ratio measurements.
Since you evoked Greg's name, let me first be clear about this. Greg is a friend of mine. Long ago we both worked at a company called Tektronix, a leading supplier of test instrumentation. We worked there at different times and in quite different capacities. Greg worked for a Division of Tektronix, which was the primary supplier of test equipment to nearly all the major broadcast studios. There is no one better at video than Greg. He can go toe-to-toe with anyone in our industry. I'm guessing we can agree on that. A few years back Greg and I had a conversation about the full-on, full off (FO/FO) contrast metric. At the time I thought it was nearly useless since the conditions could never be replicated on screen simultaneously. He convinced me that FO/FO DID have merit since it said something about the display device's ultimate ability to perform at the extremes of the luminance range. I get it. That does not mean I support it as a metric that should necessarily influence the purchase of "Display A" over "Display B" in the current product offering environment. And yes, you are correct, Greg would probably not side with me on this point. Stay with me, and I?ll try to explain why I take this position.
Not all that long ago, when the "best" FO/FO numbers hovered around 10,000:1, this metric made some sense to me in A/B comparisons. Today, and largely because of the new display technologies involved, we are seeing FO/FO contrast ratio numbers completely off the chart. I have seen advertised numbers of 5,000,000:1 and 10,000,000:1. No instrumentation we have, this side of NASA can measure those extremes accurately or with any repeatability. Even if they could, a 2X difference in results could be achieved by a one-click error in the least significant digit of even a very expensive luminance meter.
If you believe, as some of our best pundits do, that our (display) world will soon be ruled by LED backlit devices, the whole notion of FO/FO will be a non-issue. The LED boys have already stopped posting numbers. They simply say "Infinite" when it comes to contrast ratio, because an LED can quickly turn on and off completely, putting the contrast ratio denominator at zero.
Then there is also the issue of what the big numbers mean to a human being anyway. A recent paper from Hewlett Packard (another highly respected instrumentation manufacturer) talks about the inability of the human eye to perceive a real contrast ratio of anything greater than 800:1 to 1000:1 tops in a perfect specimen. One of the conclusions in the paper stated: "A higher contrast ratio is certainly better than a lower one, but the higher the contrast is, the less perceivable difference an additional increase will make--and there will come a point at which no continued increase (in absolute, objective terms) will be perceived by the viewer." Part of what I?m saying, Darin, is that I think our technologies have got us there.
Finally, it is worth mentioning that in an article about eight years ago, authored by Editor Gary Reber, where Runco was trying to establish a "new" metric for light output and "real" contrast ratio called CSMS, they concluded "The FO/FO method yields exaggerated contrast ratio measurements and is not representative of home theatre performance... Runco does not use the FO/FO method, but rather the more suitable and useful checkerboard method."
Look, contrary to popular belief, I don't think that everything Runco writes is gospel. Nor do I think that everyone else who is "on my side" is there for the right reasons. Most probably never got the real usefulness part of FO/FO that Greg explained to me some time ago.
Darin, you can make what you will of this debate, but I see it as simply an expressed opinion about the merit of one contrast ratio metric. I know you are an intelligent guy, and as such, I think you should allow for the possibility that reasonable people can disagree. Joel Silver likes perforated screens in some applications, I don't. Most of my videophile friends don't want to see anything on screen brighter than 25 footLamberts, post calibration. I like 30+. Some of these same guys insist on 2.2 gamma in their dedicated theatres, while I prefer 2.4. It seems to me we can all hold these views without someone needing to be proclaimed "ignorant."
Two final thoughts. First, primarily for continuity with the past, in future reviews I will measure and report FO/FO numbers in accordance with whatever procedure Greg used. Second, I will not get dragged into an endless public back-and-forth as I have seen many of these dialogues end up in, with the only apparent motive to get the last word in. If you would like to e-mail me to continue a discussion on this topic (or any other), I promise to be civil and open minded. I suspect if we could get past this, we could have several positive exchanges in the future.
You can E-mail Widescreen Review @ editorgary@widescreenreview.com