Film-Tech Forum ARCHIVE: Consumer DLP vs 3chip LCD or LCos

This is topic Consumer DLP vs 3chip LCD or LCos in forum The Afterlife at Film-Tech Forum ARCHIVE.

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Posted by Frank Angel (Member # 248) on 10-04-2007, 05:17 AM:

They want to buy a video projector for REAR SCREEN presentation which EVERYONE knows is possibly the WORST method of projection ever invented as opposed to front projection (and is why you see SOOOO many rear screen theatres across the country). ESPECIALLY in our theatre which is huge and WIDE, so hotspotting, which is always there even ON-axis, is horrendous at even small off-axis angles. I say front projection is the only way to go; it makes me ill that I even have to explain this to them.

AND, seems they have also set their hearts on getting some $3000 DLP unit to do the dirty deed -- I can tell they have been enchanted by the magic of the "DLP" letters -- gotta be good if it is DLP (shows IT knew how much getting that technology into theatres was going to impact consumer's minds). But if I am going to get them to use this thing for front projection, my thinking is, DLP won't get me there in terms of light output compared to a triple chip LCD or LCos projector, will it? Hasn't that 3 chip technology surpassed DLP in terms of light output and rez? Thing is, I want them to get a projector that can be used as a front screen projector and to abandon that rear screen folly. For that I need some hefty lumen power.

My question is, am I wrong to dismiss DLPs? How about stacking two? Are there any manufactures out there making DLP units with the same kind of light output as can be gotten with the 3 chip LCDs? And of course, LCDs projects without moving parts instead of that damn DLP spinning wheel which is just zipping along waiting to crash and burn.

Anyone have any suggestions about which would be more advantageous to look into -- some of the newer DLPs or the 3 chip LCDs? If you had any particularly good luck with either and a particular brand or model, I'd be happy to hear it.

Posted by Steve Guttag (Member # 268) on 10-04-2007, 10:19 AM:

You can go brighter with DLP actually, than LCD...LCD merely wins on cost. I personally can't stand single-chip DLP...it is downright annoying to watch.

LCD is not without its flaws...color stability is not its strong suit and the brighter LCD projectors generally have miserable color uniformity too. The DLP will normally have a much snappier picture too. There is just a lot of bang for the buck in LCD.

For instance, you can get a 5500 lumen 2K LCD projector (1920x1080p) with a lens for the low to mid $30K (not the $3K you mention). You'll need to add another 20-30K to do that with DLP. Probably the best bang for the buck DLP projector is the Panasonic 7000....it is a 6000 lumen 1366x768 projector using 3-chip DLP that can do HDTV quality video as well as power-point type shows and with a lens is typically under $20K. Once you go lower than that in price...you are often in single-chip DLP land so the LCD offerings look better (to me). For well under $10K you can get something like the Sanyo PLV-WF10 that is 4000-4700 lumens (depending lens) and I suppose twin stacking is possible to up the lumens and remain less expensive than a 3-chip DLP.

If 4:3 is all you are after then yes, LCDs are going to yield the most bang for the buck.

Steve

Posted by David Stambaugh (Member # 1102) on 10-04-2007, 10:30 AM:

Any projection source that uses a "color wheel" [Eek!]

should be categorically rejected. [Big Grin]

Posted by Frank Angel (Member # 248) on 10-09-2007, 06:57 AM:

OK, so I am grasping for straws here, but why exactly wouldn't this work: aside from the problems with convergence that are always problematic when stacking vid projectors for brighter output, why couldn't you take three of the high-end consumer DLP units, ones with native 16:9 - get rid of the color wheel (what do they use in those anyway -- chromatic filters for pure light....prisms?). And use a single color signal for each projector. Then you need to feed only the right color signal to each projector, which should be easy with component outputs/inputs.

Wouldn't this give you pretty much all the advantages of the 3 chip LCD projectors (greater lumen throughput) but with the DLP advantage of those deep blacks, much faster lag time and better contrast? But without the silly toy wheel spinning round and round. And they do stacking all the time, so that's not novel and they seem to deal pretty well with convergence issues.

This should work, no? How easy you think it would be to rip out the color wheels? And what would be the best way to "colorize" the three encoded b&w picture? I am thinking, use whatever they use in the color wheel, cept nail them down at the right color so they don't move. Or, if that would burn them, then take all the same color and transfer it to each wheel so you could let them spin away, but each would be one and the same color in each segment.

For convergence purposes, you could do like Kloss did in his Video Beam -- create a triangle....like the War of the Worlds Martian eye -- one on top and two below. You could invert one of the ones on the bottom so the lenses could be closer to each other and then just flip the image so it's upside down as well.

I see it as a piece of cake that should work pretty easily. But that's what things always look like before you get down to the nitty gritty of it.

Anyone have any ideas?

Posted by Brad Miller (Member # 2) on 10-09-2007, 10:02 AM:

I use Panasonic single chip PDT-3500 units for preshow advertising and they work fine for the purpose. (It's just trivia and ads!) On a screen bigger than 40' I simply stack two of them. They are near effortless to stack, even though they were never truly intended to be stacked. Just make sure your horizontal lens shift is centered and that your front feet on the top unit have about a one turn from zero on them. Align as close as you can with the electronic vertical lens shift (and physically move the top machine to match the bottom one horizontally), then fine tweek with up to a half of a turn on the top machine's feet. (Obviously this becomes a bit harder if you don't have your lenses fully zoomed in or out, as that has to be dead on the money for it to work.)

Posted by Mark Gulbrandsen (Member # 72) on 10-09-2007, 07:39 PM:

Boy I donno... stacking projectors for pre-show.... talk about eating up pre-show profits in replacement lamps! Hopefully they are pulling off alot more than pre-show with those things.

Posted by Brad Miller (Member # 2) on 10-10-2007, 12:49 AM:

Do the math Mark, it's still cheaper to get that kind of brightness AND it keeps all of the preshow projectors the same in the building. (It is only needed for the big screen in the complex.)

Posted by Steve Guttag (Member # 268) on 10-10-2007, 02:14 AM:

As one gets into bigger projectors, one is often getting into units with 2 or more lamps so double stacking has its advantages. Generally brighness in projectors will cost geometrically more...versus double stacking, which keeps costs linear with brightness. Then there is the whole redundancy thing too.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 10-10-2007, 07:40 AM:

Brightness wasn't my arguemant nor was it that you need it! Its the cost to run those two lamps. Eating up any pre-show profits yet faster. We have alot of those Panasonic and other model Panasonic pre-show projectors around here and lamp life even with the blbower on high rarely makes the rated life of the lamp. Now the iffy lamp life that may have to do with other factors such as the altitude but running two lamps simply costs more no matter how you look at it.

Mark

Posted by Steve Guttag (Member # 268) on 10-10-2007, 05:30 PM:

It might not have been your argument but it was the driving force. The feeling being that a properly presented advertisment (good focus, bright, well done) is more apt to convey its message than a drab under-lit "just thrown out there" sort of display that reminds one of the crappy slide shows that used to be there.

Pre-shows need not look amaturish and in fact such "Quality" takes away from the movie theatre going experience.

Steve

Posted by Frank Angel (Member # 248) on 10-30-2007, 04:12 AM:

I am still wondering about 3 DLPs, one for each color. Any reason why this wouldn't work? It would be a hellofalot cheaper than getting up into the really big ticket projectors.

The only problem with the cheaper units, they all have very short focal length lenses and if I am going to get up into the booth with this, I am going to need longer throw lenes. All of these things are made for conference rooms and class rooms and such and they want big pictures at short distances; I need just the opposite. And none of the projectors I am looking at have changeable lenses.

I may have to tell them to start saving up because we are going to be looking at $20K - 30K units.