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Join Date: Dec 2006
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On LCD and LCOS projectors, convergence luck-of-the-draw matters 1000x more than the quality of the lens these days. You cannot compare one LCD to one other LCD and declare one a winner in sharpness unless you have some certainty that it fits within the mold of some consensus (since convergence luck varies on a unit-to-unit basis of the same model).
Other than a couple of Sharp DLP's, I haven't seen any manufacturers really skimp on the lens too much, although I'm sure there is some exception. You could take a $900 Epson 8350 with perfect convergence and it'd be sharper than a $50,000 Sony with imperfect convergence. I am not saying Sony would approve a QC on a $50,000 projector with imperfect convergence and allow it to ship out the door, but I am just saying in general. We do know that $5000+ projectors come off the assembly line with sharpness issues sometimes though. Sure an expensive lens could add that extra touch of sharpness beyond the default max, but the maximum achievable sharpness from lenses these days is so high that it would be a non-issue for the most part, the problem is the MFR's in most cases are not able to even get the convergence nearly good enough on most units to be able to exploit the sharpness of a better lens in most cases.
I've seen even extremely cheap projectors with a cheap lens have better sharpness and focus uniformity than much more expensive projectors with better lens's, even in a DLP vs. DLP comparison. According to Texas Instruments, the main added cost on the more expensive lens's isn't really to add sharpness, it is because the more expensive units need all the extra contrast they can get and the more expensive lens's (according to TI) preserve contrast better to squeeze that last extra bit of contrast out. Apparently it is much more expensive to make the lens preserve contrast than to make the lens preserve sharpness. Also, when there are often trade-offs, it is likely harder to manufacture a lens with higher contrast and higher sharpness, the two attributes sound like they are conflicting when I was reading the TI PDF's. That may explain why many higher contrast projectors are not as sharp even beyond the convergence issue.
Take the cheap Viewsonic Pro 8200 DLP as an example ($800 new, $500 refurb), the sharpness is bordering on superb. It is sharper than most Optomas and Acers, and about equal to the Mits hc4000 overall in sharpness.The Mits hc4000 and Viewsonic Pro8200 are so close to being almost as sharp as say a Benq w6000 that I would easily say that sharpness is a zero-sum issue at this level for 99.9% of content. I can tell you there is no way they put an expensive lens in it, they just used the correct throw sweet spots for the type of lens they bought and the correct assembly process (not aligned, because there is no alignment in DLP).
The reason the Benq w6000 and w7000 are slightly sharper than other DLP projectors is probably not the lens, but it appears to be related to the higher throw ratio and the decision making process in the manufacturing related to figuring out the best way to "build around" a given lens weakness or strengths, hence because of the longer throw ratio it allowed them to set the focal point differently (1.6 min vs. most others have 1.4). The Benq w6000 having a farther throw ratio is most likely the main reason for it's extra sharpness beyond all other DLP's in this price range. This makes it harder for some people to mount, but the trade-off was a sharper image overall. Benq made the decision to focus on sharpness in exchange for a less flexible throw ratio and probably not quite as good of contrast as they could have achieved with a different lens setup.