So what projector do we need to buy?

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Comments

  • rkundlarkundla Member, Moderator, Backers, Ultimate Backer
    According to the ProjectorCentral calculators, there is no difference in the throw distances between the PJD7822HDL and the PJD7820HD. So at these short focus distances to the vat, there is probably no difference as well.
    Ron
  • Yes the calculators show them as being the same, apparently there is a discrepancy.
    Here is the page I'm looking at: http://www.projectorcentral.com/ViewSonic-PJD7820HD.htm

    in the lower right      Throw Dist (feet):  6.0 - 25.0

    the other page: http://www.projectorcentral.com/ViewSonic-PJD7822HDL.htm
                  Throw Dist (feet):  3.3 - 25.1

    They have a disclaimer about the accuracy of the numbers, but wouldn't this mean, one projector you can focus as little as 3.3 feet from a screen and the other needs to be at least 6 feet away?
    Whether that would translate into being able to move the projector closer to the vat, I have no idea.  One being close to half the min. distance of the other.
  • rkundlarkundla Member, Moderator, Backers, Ultimate Backer
    It might be a short throw lens, but the purpose is to magnify the image at short distances. Applying that to the printer, a short throw lens at the same distance to the vat as a standard lens, would have a larger projected image.

    So if you can get it closer to the vat and the focus elements can handle it, that may work. But I think mechanically, you'd have the lens so close that it would have other undesirable effects such as heat build up on the vat and excessive light bleed over the whole projection area.

    That is why projectors with a larger throw ratio will allow you to project a smaller image from further back (assuming again that the focus elements can handle it). My 3 mm lens offset modification to the Acer allows me to get 41 micron XY from the second slot versus the 47 micron that 3DFacture documented in their CW profiles.
    Ron
  • AD001AD001 Member, Backers
    I've got a PJD7822HDL purchased for another printer (self designed) and have it focused at 4 inches (lens to build plate) with about at 49/50um xy resolution. We might be able to cut down on that if desired as our unit has a mobile projector plate but we haven't bothered since it suits our needs. I can't access the machine at the moment, but for some purely anecdotal evidence I think we had been able to get it to focus down to ~3in from the build vat in the past.
  • kbvprokbvpro Member, Backers
    everyone is forgetting that there is enough room in the Draken to fit a small Projector. I have Benq and the projector is rubbing against the wall of the Draken and it is ofset to the left and not in the center
  • rkundlarkundla Member, Moderator, Backers, Ultimate Backer
    Hey @AD001 how is your ViewSonic projector working for you?

    As I was doing some reading about DLP technology, I was looking at a review of the ViewSonic PJD7822HD and saw that it was one of the projectors that was rated to actually give off the 3000 lumens at full power versus the Acer H6510BD.

    My biggest question is on how well the light uniformity is across all corners. The Acer definitely has some issues with light uniformity on the left side, so in looking for a new projector, I wanted to know if you have had good experiences with yours.

    Ron

    Ron
  • skaadskaad Member, Backers
    Now that a little time has past and more backers have their printers, what is the best projector to buy? Is the Acer H6510BD still the best choice? Has anyone had better experience with the ViewSonic PJD7820HD or its newer cousin? Has anyone had better luck with a different projector? My Draken finally arrived from its long journey and I will order the projector Friday (payday).
  • Joseph_OsbornJoseph_Osborn Member, Backers
    skaad said:

    Now that a little time has past and more backers have their printers, what is the best projector to buy? Is the Acer H6510BD still the best choice? Has anyone had better experience with the ViewSonic PJD7820HD or its newer cousin? Has anyone had better luck with a different projector? My Draken finally arrived from its long journey and I will order the projector Friday (payday).

    I'm using a Viewsonic PJD7820HD and it works as well as can be expected for what it is.  It's virtually the same projector as the Acer.  As a home theater projecter, it's really awesome.  As a DLP printer light engine, its UV uniformity across the build area and focus in the corners are not that great.  I have not attempted to re-position the lens.  I will use this printer until hopefully an inexpensive high resolution UV LED projector becomes available.
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