Originally Posted by aab1
Thanks for the explanation, but if DLP is limited to 2500:1 why is my Sharp DT-510 rated at 4000:1 without a dynamic iris? How does BenQ fake their contrast specs without using an iris? In any case the BenQ is certainly closer to its claimed 10 000:1 than the Mits is to its absurdly claimed 150 000:1.
Isn't DLP still better than LCD in terms of contrast? Why have I seen LCDs rated at things like 600 000:1, is that just as fraudulent as the Mitsubishi's 150 000:1? Would an LCD rated at 600 000:1 look much better than the HC7900DW?
I think LCOS is out of my price range, at what price do 1080p LCOS projectors start at?
I think another issue is that by projecting on a wall the not-so-black bars above and below wide movies are clearly brighter than above and below the projection which is real black, my DT-510 shoots on a screen with a black border around the image which hides the not so black bars, I think once I have a proper screen with black borders the blacks won't bother me as much. It's mostly the projectors blacks against the "real" black outside of the projected image on the wall that bother me, the contrast within the image is pretty good.
About the image going blank every few minutes for a few seconds, it has never done it when sending a 720p signal for hours, I thought it was my super cheap HDMI adjustable angle connector behind the PC degrading the signal too much so I removed it and put it back to 1080p and the image has gone blank at least once so far without the adapter. I definitely think the image going blank is a signal transmission issue and not a problem with the projector, it seems like the 1080p signal is getting some corruption every now and then causing the projector to "reset". What can I do about this?
I am sorry for you misfortunes with the Mits HC7900. As others have mentioned, I believe that something is wrong with your unit or it is simply not setup/calibrated correctly.
In regard to your question about native contrast and the Sharp unit: The Sharp unit has the Dark Chip 2+, which gives it a native contrast of 2500:1. However, it also has a fixed iris installed that reduces stray light in the light path, giving it increased on screen contrast. The Mitsubishi has two contrast advantages compared to the Sharp. It has a Dark Chip 3, which should inherently increase the contrast on screen. Also, while having a fixed iris in the light path (like your Sharp DT-510) it also has a variable iris in the light path as well. This, for all intensive purposes, should increase contrast to a noticeable degree. See this source for iris information
Now, you said that you projected the images at two different sizes, not a good idea for accurate comparison. For a fair comparison, you have to calibrate them to the same max output with a full white signal, calibrate brightness and contrast (at least), and then project them onto the same material of the same size. Only then will you observe an accurate comparison. Of course
the Sharp will at least have some advantage to the Mits when the Sharp is projected much bigger and therefore it lowers its overall brightness and therefore the black level as well.
I am not positive on how BenQ obtains it contrast spec but I suspect that it is via yet another mechanism, different from the ones mentioned, namely, lamp dimming (which is effectively the same as a dynamic iris in front of the lamp but differs from any other type of iris, dynamic or static, that is further down in the light path).
Your question about "what is better" is simply too broad to answer accurately. LCDs are usually superior to DLPs (in the same price range) when full on/full off contrast is the criterion for picture quality. The LCDs may have a more aggressive iris or greater native contrast inherent in the panels for this criterion. However, intra-image contrast is a completely different story as well as different types of other contrast measurements. As most know, a contrast spec of 600,000:1 is exaggerated and only obtainable on "torch modes" with all dynamic contrast options enabled. Torch modes are extremely contrasty and extremely unwatchable. Calibrated contrast will be much lower but still superb (especially on the Epson Ultra Black models). As a member said above, the Epson, while better in some respects to the Mits, actually falls short in his opinion to the overall look of the Mits. Surely this difference is down to an issue of preference rather than absolute differences (wherein everyone would agree with), nonetheless, I would agree with him.