Projector position question

Glenzippy,

Thank's so much for the quick response, but I think you got me slightly more confused:


You indicated that 14' should work fine for both projectors, but the pani calc, says the throw should be 24.3' ?


May I ask you how big your screen is? and How far your projector is from the screen?


And thanks for helping get things thru the budget coordinator, it's not the "just buy it" it's more of does the BenQ kick so much more then the Pani that it's work ~2k more. Having not seen either projector it's very hard for me =(. I am really basing my oppionions on what I read, and that's leaning me hard towards the Pani.


Also, could I use the Pani on a 104'" 16:9 screen? PC says that the image would be to bright, I guess that is what causes the screen door effect?


Sorry, for any stupid questions, I am trying to learn and at the same time get this right the first time =).


Thanks!

The Panny can shoot a 120" diagonal pic in a range of distances from 12.1' to 24.3'. !!! I didn't look at the BenQ.


I'm assuming you're using the projectorcentral calculator...


If you know your desired diagonal picture size:


In the "zoom box", click "throw range" button. This will anchor the pic size (at 120" diag or whatever size you want). The green range in the "throw distance" linear graph underneath (and also in the "zoom box") is the range of mounting distances you can use for a 120" diag pic.


Just "grab" the blue slider in the zoom box with your mouse and slide it up and down, the diagonal size won't change, but the throw distance and zoom amount will.


Also useful if you only know ONE dimension of screen size (say the max height or max width). Just set it, and the calculator will figure the rest out for you.



If you already have (or desire) a certain fixed mounting distance (aka:"throw"):


Leave the zoom box in "diagonal range". This anchors the "throw distance" to whatever you want, and then you can see what range of picture sizes you can project from that distance (for that particular PJ).

Glennzippy,

How far is your projector from the screen roughly?


And thanks for the "future proof" advice I will definately be doing that, I think

what I am gonna do is run component, dvi/hdmi, cat5e and then run a conduit in addition that for anything else that might come up.


Thanks !

Quote:
Glenn,


My understanding is that it is better to have the projector further away (given it is in the throw distance). The further away, the less distortion from having the PJ try to fill the screen at a steeper angle (I'm sure I'm not saying this right). In an extreme example, let's say that a PJ could fill a 100" screen from 1' to 20'. If the PJ was at the minimum (1'), it would have to throw the image at some pretty wild angles to fill that space, creating distortion. Take it to it's other extreme - there's less distortion. Or at least that's what I understand.


Of course that's extreme and it might not matter if the PJ is 14' or 20' away. At that range of distance (speaking for the Panny), perhaps the distortion is minimal. However the reason I'm currently leaning towards the Panny is it's long throw distance - it will be further from the seating area (noise/heat) and it was much easier for me to run conduit & electricity to a rear mounted PJ area. Plus sound control is important to me - I use wall sconces, no ceiling cans or other holes in the ceiling. And if my understanding is correct, I may have a sharper image.


By the way, I like your projector niche - that gives me some ideas!


Bob

Common all you experts out here.... Clear this up for us less than expert newbies.


Closer to the screen = brighter picture?

Closer to the screen = keyhole / distortion possible



further away = less bright picture

further away = little to no distortion or keyhole correction



Is this correct? For me I have a 21' room and will most likely project onto a 112" 1.85 Carada. I want the best of both worlds but am concerned about the brightness factor if I opt to get the high contrast grey screen (.8 gain). I willl have fully controlled lighting. I have concidered placing it at 15.5' or all the way in the back in its own little bubby hole like glenzippy.

Quote:
Again, I'm no expert, but my understanding is that being close does not mean the image will be brighter (especially with a projector screen). The reasoning is that the surface of a screen is not flat, it is textured. Now if you place a projector close to the screen (lets say right in the middle of the screen), to fill the whole screen the lens has to throw it's image at an extreme angle. So when the light hits the area of the screen not in the middle, it is not hitting the textured surface straight on. The further the light has to go to the edges, the more this is true.


Now take that projector and move it back. The light hitting the screen is more 'dead on', meaning the the reflection of the image back is going to be brighter, as it is hitting the screen at a better angle. So (given the lumens of the projector and it's throw distance), the further away, the better.


This comes from someone who doesn't currently own a PJ, so take it for what it's worth. I'm going with a long-throw projector (Panasonic AE-700 - w/ a $200 rebate just announced - http://www.avsforum.com/avs-vb/showt...hreadid=515072 ). For the reason mentioned above and for convenience, I am shelf mounting it at the back of my HT - about 19' away.


Bob

Lawerence,


You're probably right. And can someone see the brightness difference by moving the PJ a few feet? Probably not, at least with most newer PJs.


That being said, I wanted to find the source for my understanding of brightness & screen distance. After some digging, I found it - it was from a ProjectorCentral.com review of the AE 700 vs. the Sanyo PLV-Z3. Here's what they said:


"For those whose rooms allow options on projector placement, a longer throw distance is the better choice. That is because you want to create a narrow cone of projected light so that the light strikes the screen from edge to edge as close to perpendicular as possible. This will produce a more even reflection of light from the screen. Ideally, we like to avoid the extreme ends of the zoom range also since lenses tend to be less optically efficient at their extremes." ( http://www.projectorcentral.com/pana...0_sanyo_z3.htm )


Whether or not this is true or noticable, I can't say. However after reading this several months ago, my decision was made as to where I place my PJ. Having it at the rear made it so much simplier (in terms of conduit, etc.), plus I save on the expense/hassle of the ceiling mount. My ceiling has no cans or other breaks, keeping the ceiling intact (for sound purposes) also played into my PJ positioning.


Bob