Projector Question

[stevehookem]

Looks like I am getting an Optoma ep709 projector from a colleague for free. It's never been used, just sitting on a shelf in the box. Woo Hoo.

This is a XGA DLP projector that is 1800 lumens, 2000:1 contrast and DVI inputs for HD. I've been reading the manual online and it looks like the minimum diagonal image at 5' is 35", max is 38". This doesn't seem to good to me. However, I am going to put the sim in an empty bedroom so the projector can either be on the ceiling or on the wall behind. I would like it on the front of the sim if possible.

Question: how close to the screen should I be with the pit? My screen is 63" x 63 (85" diagonal) and I can get the projector about 10' back from it. If I put the projector in front of the MIP (on the shelf where my monitor would go) I would then push the simpit back to allow for the largest image. However, I am thinking that this might not look right--shouldn't the outside view be fairly close to the simpit?

[beaky]

That's a real good question.
You'll probably want to experiment: with different distances, and with different view magnification settings in the sim.

If I were you, I'd start by getting your setup as close as possible to the largest possible projected image (before you start casting a shadow on it), then take it from there.

[stevehookem]

If I mount the projector on the ceiling, any idea (approx) how close I could get before the image hits me? The screen will be up some off the floor. I'm planning to make the bottom of the screen just below the height of the MIP.

I know for HT you usually sit back 1.5X the screen size. That can't be the same here. I would think you would want to be pretty close in to the screen.

[beaky]

It depends on the angle the light path is making. I have no way of even guesstimating without knowing the characteristics of the projector (Short-throw lens? Zoom? Offeset image center, or centered with lens? Image size over a given distance?)

You can experiment (move your chair closer to the screen until your head casts a shadow), or make a diagram based on the known image size at a given distance, draw a line from the bottom of the lens to the bottom of the screen, measure your height while seated, and place yourself and your controls at some point just beyond where that height "bottoms out" on the light path.

The first method is much easier...

If you're lucky, you'll be able to get an image the size you want, but not end up sitting too far away for your liking. As far as what that distance is goes: forget any rules you may have heard, and just experiment. It's very hard to tell if it will be sharp enough yet panoramic enough, etc. until you sit there looking at it.

[JBaymore]

Steve,

Tohelp you out... maybe try here:

http://www.projectorcentral.com/Sanyo-P ... or-pro.htm


best,

.....................john

[stevehookem]

John,

I'm not trying to find out how big I can get the image in my space. I know that I can put the projector in the back of the room and fill a wall if I want.

What I am trying to figure out is how close I should be in the simpit to the screen. For home theater, they same sit back 1.5X the screen size. However, in this situation, I would think you would want to be much closer to the "outside" view through the windscreen. Right?

[JBaymore]

Steve,

Nope.  If you have the space, you want your eyes to have to focus far away when looking "outside" and then to change to close range to look at the cockpit instruments.  This is the way it happens in the real world....and why a flat computer screen with both outside view and panels is so "fake" looking.

This is part of what collimated displays do so well and what makes them feel so real.

I have seen people post discussions on the web about geting the real world objects to be the exact same size from the pit views as they are in the real world from the cockpit........ but to me that kind of stuff is in the "obsessive - compulsive" trange of behaviors  ;D .  It gets involved in a lot of math stuff.

best,

.................john

[stevehookem]

Well good! That makes it easier. I'll project for the largest image I can get from about 12' back and move the simpit back as well. Cool!