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Question about my Sony VPL-PX21 Projector

5K views 7 replies 4 participants last post by  peterrow 
#1 ·
I have a Sony VPL-PX21 projector that I got for free. It is 1800 Lumens with a native display of 1024x768 and a max display of 1280x1024.

I would like to project onto a 16:9 screen, after some testing it appears that I can change my image from 4:3 to 16:9 but when in 16:9 mode I have the black bars at the top and bottom.

Does this mean that a 16:9 screen will not work for me and I should make a 4:3 screen instead? I can make the picture go to 16:9 but can't seem to get rid of the black bars so I am really projecting 4:3. I would rather make a 16:9screen but it doesn't appear to me that this can be done properly with the projector I have.

Any thoughts?
 
#2 ·
That's quite a projector to get for free.


If you take the ratio of your LCD panel (native), which is 1024 x 768, I think you will find that the aspect ratio of your projector is abot 1.33:1 (4x3), just like a regular tv set. Therefore, you cannot project a 16x9 image from it without black bars on the top and bottom, or the image will not be in the right aspect ratio. Without the black bars, the image will appear tall and skinny. You can set your projector to do this, but the only reason to do this would be to use an anamorphic lens to optically shrink the image back to its regular size--thereby projecting an image at its proper aspect ratio without the black bars.


Check out the following for a primer on anamorphic lenses:

http://www.projectorcentral.com/anamorphic_lenses.htm


There are projectors that have a fixed panel of 16x9 which would display 16x9 material without black bars (so-called anamorphic DVDs would allow the projector to eliminate the black bars so the entire LCD or DLP panel is used. However, with 2.35:1 ratio material, you would still have black bars. On these projectors, you could use an anamorphic lens to get a nice, wide cinescope picture without black bars.


(Incidentally, I have a 4x3 projector that I project onto a 16x9 screen, with an anamorphic lens--it looks great!)
 
#3 ·
That was a good little article, thanks. I went to panamorph and that is just way out of my price range.

What do people do in my situation? Do they build a 4:3 screen and just deal with the black bars? I guess the best thing for me to do then is to build a 4:3 screen correct? Thanks for your input.
 
#4 ·
You might consider building a 16:9 screen anyway. Then overscan the screen by either zoom or choice of throw distance, and force most or all of the no-picture bars off the screen above and below it. This wastes some pixels that are always black, but lets you watch widescreen material on a "full" screen (unless it's wider than 16:9, as Steve pointed out).


When we built our outdoor screen, it wound up as 16' wide (longest piece of 1X3 I could find) by 7'9" (tallest I could fit in the garage for storage!). That works out to about a 2.06:1 aspect ratio, sort of between 16:9 (1.78) and 2.35. We zoom to fill either the height or the width as needed using an InFocus 4805, native 16:9 PJ, and then live with any remaining black bars, which outdoors at night disappear if contrast et al are set right.


In any case the idea is to get out in the yard and have fun; the screen shape will never matter to your guests.


Mike
 
#6 ·

Quote:
Originally Posted by 1critter /forum/post/11591886


...if the black bars that are overscanned off the screen will end up lighting whatever is behind the screen?

If the brightness/contrast settings of the PJ are close to correct, the black bars outside the active picture will be just that-black, or maybe one or two units into grey just above black. Use one of the test DVDs or the THX optomizer found on some DVDs to help calibrate your PJ.


The bars may be just visible, depending on what the spill of the overscan hits, but it will be WAY darker than the active picture and IMO not objectionable if even noticable.


It would be easy to try some of this out before building your screen by hanging an old bedsheet or even projecting on the side of the house, just to get a feel for things.


This is a hobby; it's FUN to play with things until you are ready for a public opening!
 
#7 ·
Your absolutely right about it being a hobby and fun. I actually have already projected on to a off white bedsheet with a tarp behind it to help contain the light and it looked really good, I can just imagine how it will look projected onto a proper screen surface.

When I did the bed sheet test is when I noticed the black bars but then again, the video has not been properly calibrated. I have the Digital Video Essentials DVD so made I would benifit by using it on the projector.

I have been contemplating building a screen but then I see the 149" Gemmy that is really inexpensive, any thoughts on that one?

Honestly the screen i was going to build was not going to be as big as the Gemmy because of storage issues and the Gemmy seems like it would fit the bill in that aspect.
 
#8 ·
I also aquired this projector for free but would like to sell. I have not seen any projectors of the same model for resale on the internet and wondered if anyone knew the best site or way to resell it. Any info would be greatly appreciated. I love this projector and it is barely used but it is way more than I need.
 
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