At the office I've made different experimentation on spactator distance VS image size (with our commercial projector).


If your room is only 10' deep, a 120'' diag projection will be too large for your eye. The eyes/brain cannot concentrate on this large image if it moves. This is specially true during video game. YOU should a t least have a distance/size ratio of 2:1 or better 3:1.

Otherwise you will feel strange occular fatigue very soon,. Try this at the theather on take to front seat just for fun, would you watch 2 movies in row ?

So for a 120'' PJ you need a least 20' to avoid feeling occular fatigue. Closer you will be of the screen sooner you will feel it. If you plan to use your PJ only for watching movie (1h30 average) it's OK to have a large screen but for a full night of video game it's going to be very hard for your eyes.


SO before thinking going for a larger LCD than a 17'' just to have a larger screen you should think of that very carefully.

Alternatively if you're a searious doom3 adrenalin junky, hocked up on pro plus and a crate of coke, who likes having the absolute stuffing scared out of them at 3am with the sound turn up and all the lights out then all you really need is a gamming seat welded 5ft from the screen to really get the night going!!!

You're right on that point :-) But you gonna have to suffer with your "red eyes"....

No pain no gain!

[/QUOTE]YOU should a t least have a distance/size ratio of 2:1 or better 3:1

I have measured the width of the picture at my favoite cinema. Its 16 metres/52feet. My favorite seat is 13.6metres/44.6feet back from the screen which would be very close to centre of the room. The back row of the cinema might be a little over 16metres, certainly nowhere near 32metres(2:1)
This scenareo I think would be consistant with most modern cinema complexes.
I measured it up because I want to replicate the true cinema experience at home, so I will be sitting somewhere around 1:1

anakin,

You are correct, anywhere between 1.8-1.2:1 is a good distance. It depends on preference, some folks like fronting row style cinema, others like middle or back- row. I currently sit 1:1 and find it fine for 16x9, however a bit large for 4x3.

Cheers,
Lee

Amid scattered popcorn, chewing gum and orange peel underfoot ?

I love the cinema experience and each time I'm there I find my eyes needing to move a lot to take in the entire screen once the movie starts. But I'm sure you'll all agree that you don't really notice it after very long. I always try to pick a center seat forward of the middle row and have watched double features without any adverse effects One of my favorites is to sit in the front row of the Boeing IMAX Theater to feel fully submersed in the experience. That's the point of the theater, to put yourself fully into the movie using a large scale. To say you need atleast 2:1, 3:1 preferred, ratio to avoid occular fatigue is a bit much. You don't sit 4+ feet back from a 17" monitor do you? It's all to personal taste, so don't be scared off from the giant screens if you've been dreaming about them like I have been since I signed up.

...only thing worrying me with sitting around 1:1 is screen door effect and other visual anomolies becoming visable.

Screen door won't be but compression artifacting might be.

I guess i might depend on the physical of the person. Me and my girlfriend went to theater yesterday and got only 7-8 row seat, after 1 hour I was baely able to keep my eye open, not because movie (its was cap'n sky...) but just fatigue.

It would be interesting to see difference with/without ambient light if it does matter....

Sorry CBR_MAN I have logged over 230 hours on my PJ with over 16 straight for 3 consecutive days and I did not feel any fatigue... other than passing out at 5am every one of those days but i had run out of iced tea by then currently just finished a 28hr run (watched all last exile, flcl, some naruto, prince of tennis, full metal alchamist, gundam seed and some full metal panic) I feel fine today and look foward to spendig some quality time with my girlfiend watching some movies she wants to see....

Ezra

Hi Guys,

Watched back-to-back flicks last night on my pj sitting at 10' with the project just behind me. Flick number one "The Punisher" Flick number two "Man on Fire"

I had no problem at all sitting and watching both movies back to back... I loved every moment. What I have noticed now that I have logged many, many hours of movies on my projector, both with a Viewsonic N6 and a HTPC.

As suspected many DVD movies have less then great source. Some DVD's are captured from a source that is less then great for expanding to the size we are watching. Others, mostly Animophic have stunning picture quality. I really noticed this last night watching "The Punisher" nice, sharp, but less then it could have been. The moment I tossed in "Man on Fire" I looked at my other half (Cathy) and said "wow, this film looks way better", I could not believe the sharp detail in the distant shots and text.

All DVD are not created equal, if anyone has more knowledge about source for DVD and why some DVD movies look so good and others don't, feel free to chime in, I don't have a ton of time to research.

Cheers,
Lee

I just started a thread earlier today in the General Discusion category entitled DVD image quality.

Tons of those old movies were converted to video a long time ago (beta). When they dust them off to release them they start with those old beta masters and (surprise) upscan them. The target audience is TV viewers (interlacing, VHS type bandwidth).

SWEET someone who knows about LAST Exile!!! I love that series. Anime junkies unite. Anywho... I have watched my projector for a maxium of 8 hours of normal tv, playstation playing and movies all at once and loved every second. So knowing this and looking at some of the other responses, I have concluded that your hypothesis is incorrect (to say it nicely).

GO LAST EXILE!!

P.S. The Punisher was filmed with High def cameras, it looked awesome on my projector. I'm not sure why it didn't look good for you. Btw the dvd isn't HD so nobody bite my head off for thinking I'm mistaken . I d/l a clip of the HD version at 720p and it was awesome. I don't remember where though. Maybe you could run a search. It was like 160MB for 2:30 mins!

-Jeremy

Jeremy,

Don't mistake less quality for poor quality. The punisher did in fact look great (Better then some) on my projector, however, Man on Fire looked at least 2x better.

Why? I am guess better media + source.

Give er a try some time and really look at the distant figures, like faces in the far distance and so on, you will notice that Man on Fire is more detailed and sharp on small details.

Cheers,
Lee

Yes, but don't forget that the original source, style, lighting and lens (as well as film stock) is a chosen as part of a consious design and plan by the films original cinematogpher working with his creative team (director & production designer).
My point being that what your seeing could be be design and not flaw...

[QUOTE] Screen door won't be but compression artifacting might be.

OK, what is it? and how do I lose it?

there's another factor about quality, the problem with mpeg2 is that it do not deal very well with fast moving image (sport, action movie, porn , etc) this create compression artifacts.Veriable bit rate often can improove the quality b ut I dont know if it is used on commercial DVD.

Back to screen size and viewing distance: I read somewhere that THX spec show a ratio between the WIDTH of the screen versus distrance from the screen. The optimal ratio was 1.6

There's an old thread I was looking for where JonesRush was discussing this very topic. I can't find the link that showed the calculator for viewing distance, however.

There was this site on the internet that had a few different home theater calculators on it and one of them had to do with standard viewing distance versus THX viewing distance. Anybody remember what I'm talking about?

OK, I found the specs for THX. THX says that the last row of seating must have a 26 degree viewing angle or better. THX also recommends an optimum viewing angle of 36 degrees.

So, the width of the screen for a 120 inch 4:3 diagonal is 96 inches.

The optimum viewing distance = Width/(2* Tan(36/2)) = 96/(2 * Tan(18))) = 147.7 inches (12.3 feet) from the screen.
Roughly a ratio of 1.5:1 distance to screen width.

The maxiumum viewing distance = width/(2* Tan(26/2)) = 96/(2 * Tan(13)) = 207.9 inches (17.3 feet) from the screen.
Roughly a ratio of 2.2:1 distance to screen width.


So, lets turn this around. Let's say you know how far you can be from your screen based on your room size. And you want to calculate the screen size based on the above.

For 36 viewing angle:
Width = VDistance * 2 * Tan(36/2)

For 26 viewing angle (minumum):
Width = VDistance * 2 * Tan(26/2)

Example:

I sit 10 feet from the screen. That's 120 inches.
For 36 viewing angle:
Width = 120 * 2 * Tan(18) = 78 inches optimum screen width.

For 26 viewing angle:
Width = 120 * 2 * Tan(13) = 55 inches minimum screen width.

For a 4:3 screen using 3:4:5 rule on right triangle yields:

78 / 4 = 19.5 , 19.5 * 5 = 97.5 inches diagonal screen size for optimum

55 / 4 = 13.75, 13.75 * 5 = 68.75 inches diagonal minimum screen size.


If you take these numbers I just came up with and plug them into the LumenLab calculator, you find out the projector using the original plans and the original lens must end up between you and the screen for you to view an optimum screen size. In any case where you are in front of the projector, the screen is too big.

This shows the real need for the pro lenses Brain has created.


Thanks,
Zendance