Axiom Home Page Forums General Discussion Home Theater 235:1 screen size input

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Yes Bruce, 14.8 is correct. Based on your screen size, you could place the projector anywhere from about 7.4ft upto 14.6ft or so Throw distance. So you would be placing the projector at the very MAXIMUM throw and you would have to leave the ZOOM at a minimum to fill the screen. Sometimes it is better to place the projector at a location so you have a little more flexibility and can adjust the zoom if needed.

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So I should place the projector further back to use a bit of the zoom?

Just want to make sure your doing this right, ok if your wall is 12ft wide and you want to leave 2ft on each side, that leave 96" for the screen.

So your 2.35 screen will be 96" wide and 40.8" tall (96/2.35). So when you say you penciled in the screen, I assume your saying you drew a 2.35 screen?

Your native projected image will be more like 40.8" x 72.6wide (40.8 x 1.78).

The best thing to do is try to place the projector where you think it will be, and fire up an image on your wall, just to make sure things look right, at least in 16:9 mode, maybe you've already done this....

I think the S97S is a great DVD player, I assume your going to feed the projector via HDMI connection? If your projector will allow you to stretch the image over HDMI you should be good to go. On my Z2, it would only let me stretch the Component signal, not over HDMI.

I bought my S97S back in mid 2005 and it isn't even broken in yet. hmmmm maybe we should talk......since I took the HTPC route. If I had the Z4 I would keep the S97S, great picture and sound in my opinion.

The only two brands I'm aware of that make Horizontal designs are:

http://prismasonic.com/english/

and I believe www.panamorph.com just came out with a Horizontal stretch design, they used to be all vertical.

I got my Prismasonic H600M back on AVS when they had a power buy, I think I payed around $700 or so bucks...not cheap.

If you place the projector any further back than 14.6ft, you can't achieve the screen size your wanting. If you go to the calculator and adjust the bottom numbers to show your desired screen size for 16:9, then look over to the left above that, it will show you the min/max throw distance you can place the projector to achieve that screen size. 14.6ft is the furthest back with no zoom, if you increased the zoom the picture would not fit on your screen.

If your set on that screen size, you might want to move the projector a little closer if possible, just so you have a little more comfort zone, in case you do have to play with the zoom ever.

Hope this makes sense.

On my Z2 at about a 13ft throw distance my 16:9 image is 51" x 90", and that is with the zoom not really being used much.

I would say if you can keep it closer to 14ft or a little less, that would be better.

Ok, another thing you guys need to consider in order to be a good candidate for a constant height setup, is that your DISTANCE to WIDTH (16:9) image, has to be at least 1.3 or greater to give you decent performance. Once you start getting 1.3 or below, you will start to introduce the pin cusion effect and barroling. By my calculations both of you should be better than my results, and I love my results.

http://prismasonic.com/english/compatibility.shtml

First, lets look at Mr. Drew:

He said his back wall was 12ft wide, and he wants to allow 2ft on each side for speakers and whatever. So that gives him 8ft(96") for the screen width of his 2.35 screen.

41" x 96" would be his 2.35 screen size.
41" x 73" would be his 16:9 native image from the projector.

Lets see if he is a candidate for a Prismasonic Lens. (note: I think Panamorph follows the same guidelines?)

1. Calculate or measure the throw distance (D) and the screen width (W). (note:use the width of the non-stretched 16:9 image for calculation)

D=12ft (144") and W=71.2"



2. Count the ratio between the distance (D) and the image width (W) Ratio = D/W

(Again, the ratio is defined from the original, unstretched image)

so we have 144" / 71.2" = 2.02 ratio

3. Long throw optics gives best result, see the picture below.


So you can see that Mr. Drew, having a 2.02 reading is well into the Green area, which should give good results.


Lets look at Bruce now:

His screen results are as follows....

35.75" x 84" would be his 2.35 screen size.
35.75" x 63.6" would be his 16:9 native image from the projector.

Lets see if he is a candidate for a Prismasonic Lens. (note: I think Panamorph follows the same guidelines?)

1. Calculate or measure the throw distance (D) and the screen width (W). (note:use the width of the non-stretched 16:9 image for calculation)

D=14ft (168") and W=63.6"



2. Count the ratio between the distance (D) and the image width (W) Ratio = D/W

(Again, the ratio is defined from the original, unstretched image)

so we have 168" / 63.6" = 2.64 ratio

3. Long throw optics gives best result, see the picture below.


So you can see that Brucey Boy, having a 2.64 reading, will also most likely have great results.

The longer the throw distance the better. Having a bigger screen is also nice if your room will accomodate one.

Hope this all makes sense.

ps: Just to let you two know, my Z2 is a little over 13ft back from my screen which is:

51" x 120" 2.35 screen size
51" x 90.7" for a 16:9 image

So my ratio is 1.78, a little below both of you and mine works great. I love my HUGE screen.

Thanks ever so much Randy. The ceiling is the last bit I will be installing so I have time to play with the end projector mounting location. I will look into this further. The one thing that I do know so far is that I will be going with a LCD projector over the DLP. There seems to be better pricing and a little more flexibility.

I've heard some poeple say that HDMI was yielding a "better" picture than component connectors. I find that difficult to believe (have not seen any demo examples). There is also other information that seems to indicate degredation in signal quality with longer HDMI runs (typical of a front projector system). Have you come across anything to confirm of deny this?

I see I screwed up on Drews measurements a bit, his width would actually be 73", so 144" / 73" = 1.97 which is still pretty good, and a little bit higher than my 1.78 outcome...

Another key to help reduce any problems is to mount the Anamorphic lens as close as possible to the projector lens. Keeping in mind you want to leave enough room if you have to reach any adjustments on the projector.

Bruce, well I do think that HDMI does provide a sharper image overall, but Component is still very good. If you run your cabling, it might not be a bad idea to run both, like I did...I purchased both my 25ft DVI/HDMI and 25ft Component cables from Monoprice.com very cheap and they work great.

If your going to use an upconverting DVD player, most of them won't upconvert via component, only over HDMI. With the Panny S97S and my Z2, the picture was nicer via 720p or 1080i versus component. With HDMI the signal is digital from point A to B, component goes through conversion from digital to analog and analog back to digital, I believe.

My runs are 25ft long, and I have not had any issues with signal loss or picture degregation.

If I recall correctly from some AVSr's, the Z4 will do the stretch of component and HDMI signals, that is cool, all you need to do is find a good upconverting DVD player. My Z2 will not stretch HDMI signals, so I was only able to use component, until now, now that I have my HTPC.

Thanks for the very helpful responses Randy. Very much appreciated.

No, I don’t have the projector mounted yet, so I just measured and drew the screen size with a perm marker. I will play around with it some more when I get the walls painted with primer and projector mounted.

Bruce,

You should look at the Optima HD 72. It is supposed to be one of the few projectors that work very well with a 2.35 screen and actually has menu options for setting it up for this screen size (I’m fuzzy with the details). Some very positive posts about this projector on AVS. I would have bought this model, but I got my Panny for $1400 after the rebate. Hard deal to pass up.

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You should look at the Optima HD 72

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Thanks for the info. I will check it out as well.

I guess I will aim for a throw distance of 13-14 feet max. I figured that I just did not want to have the project directly over where we sit (approx 10 ft). Seems some of the new projectors have a very low noise factor so it may not be an issue.

I have always run my Z2 in Low-Lamp mode, and you don't even know it is above you. The projector is actually above the people in the first row, and in front of the people in the second row. Since my ceilings are 9ft, it is a none issue.

If you have light control of your room, I would also consider running your projectors in the low-lamp modes. Besides, they will last much longer if you do, in high lamp mode the fans have to run faster to keep the bulb cool, creating more noise.

Yaha 9ft, eh?

Unfortunately my ceiling will be about 6.7 ft

Definitely will have control of light. Do you have any ambient light in the space while watching or complete black? I've heard that it is recommended to have some light behind the screen to ease eye fatigue. I thought this would only be applicable to big screen and wall TVs.

Low lamp mode makes sense. Likely it would negate any need (if any) for any light in the room.