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Discussion Starter · #1 ·
It’s true. Let me explain how in my experimentation I arrived at this conclusion.


My home theater has recently been treated so that the walls reflect hardly any light. It is in a word BLACK. The matte white screen is 8’ horizontal. The normal viewing distance is 12’. From this it is easy to derive that the projected picture takes up 40 degrees of my visions approximately 180 degree range.


Question: How large of an angle is necessary or desirable for home theater? I believe that at least 30 degrees is required to simulate us appropriately.


One of my most pleasurable viewing experiences has been to watch (HD) movies in this type of room. The lack of light entering the eye from the sides, and yet the great volumes entering through the front (in a controlled manner) is ideal. We might consider naming this (measurable) effect the “contrast ratio of the roomâ€.


The greater this contrast ratio is, the easier it becomes for the eye-brain system to seamlessly and effortlessly integrate the central focus area with the eyes (normally ignored and irritating) peripheral vision area. The visually stimulating effect is just wonderful for home theater. Astronomers get a similar effect when viewing the sky far away from any earthly (side) light. Or sportsmen with their side-light blocking sunglasses.


But what does this have to do with glasses? Simple: they physically break the link between the central and peripheral areas of your vision. The glass itself also reduces the contrast, further degrading the enjoyment. The effect is at its worst during dimly lit scenes as the pupil reaches its maximum aperture.


As a non-perfect analogy consider:

1) drive in a car on a darkened road

2) turn on the interior light

3) stop the car get out

Under what conditions can we observe most accurately?


Note1: For the standard TV viewer in the standard room this discussion has no bearing, as the image only takes up a few degrees of the eyes vision area.

Note2: For some the topics here are basic. I raise them because 1) they are important to home theater and 2) they are hardly ever discussed and 3) it helps explain the considerable variation of opinions.
 

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Lenses with a good substrate-matched anti-reflective coating and minimal vertex distance (distance Rx from eyes) will reduce aberrations. Also single vision lenses will be better than progressive.


Or just try contact lenses.
 

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For those whose eyes aren't "contact friendly", I suppose that not being able to properly focus on the screen is of no relevance :D


Which is the worse experience? Hmmm..


Uncorrected:

"Well, I think it looked about as good as every other movie, ie a big amorphous blob".


Corrected:

"Ohh the details".


Cheers,
 

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I guess it's kind of similar to the discussion of 'film-like' vs. video in other threads. When watching HD without my glasses the picture looks great but slightly out of focus (I'm getting old!). When I wear my glasses (with anti-reflective coating) the picture 'pops' and is more vibrant. Depending on what I am watching I'll wear my glasses (HD sports) because it makes the picture more 3-D like. So when I want a softer film-like picture I don't wear them (aka built in film quality filter!) Too bad you're not in Atlanta Eyedoc, I need to get my eyes checked.
 

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Quote:
Originally posted by rogo
One word: lasik.
yeah great suggestion, i did it and now i see ghosting and oter problems whem it is dark.

I see every lamp twice. If i could turn it back lasik i would.


but its only a one way ticket.
 

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Discussion Starter · #12 ·
To calculate your images horizontal field-of-view (FOV) use the following equation:


FOV = 2*ArcTan(0.5*screen width/viewing distance)


Example: 8' horizontal screen being viewed at 12' the FOV is:

FOV = 2.0*ArcTan(0.5*8.0/12.0) = 36.87 degrees
 

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Quote:
Originally posted by John Kotches
For those whose eyes aren't "contact friendly", I suppose that not being able to properly focus on the screen is of no relevance :D


Which is the worse experience? Hmmm..


Uncorrected:

"Well, I think it looked about as good as every other movie, ie a big amorphous blob".


Corrected:

"Ohh the details".


Cheers,
Funny you mention that - one time I went to the cinema and forgot my glasses! The movie started in 5 minutes - but my eyes were not as bad back then so I decided to see it.


Oh, and it was pretty awful. The projector in the cinema was out of focus, so everything was blurry.
 

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Well, I thought I had something. Based on the feedback from this thread, I had found my new upgrade. I didn't need 1080P, I didn't need 10000:1 contrast, I didn't need Blu-ray or HD-DVD. What I needed was to just take off my damn glasses and I would improve the picture.


So last night I fired up the projector, sat back and un-donned my 4 eyes to install my 2 eyes upgrade. And indeed, all those other upgrades were pointless--not because I was overwhelmed with a new sense of realism...no because, I could no longer see the screen well enough to see if it was 1080P or 1P, if it was 10000:1 or 1:1, if it was Blu-ray or VHS in SP mode!


Well, it took me about 5 minutes to fumble around the theater, but I finally retrieved my spectacles. All I have to say is bring on the upgrades, cause this one is going back to the shop...
 

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Discussion Starter · #16 ·
The point of this thread is that even if a home theater viewer has 20/10 eye-glass corrected vision, they are still at a disadvantage as compared to a viewer (with similar vision capability) without eye glasses.


Ever wonder why many motorcyclists prefer not to wear helmets in spite of the safety benefits provided? Why do IMAX theaters exist? Why do theater viewers prefer stadium seating? Why did HDTV change to a wide-screen format? In fact is gets very basic: Why does home theater even exist (and all-of-a-sudden is growing so rapidly)?


Answer: People enjoy being immersed by their surroundings (simulated or not). For maximum effect this requires two good/corrected eyes and an unobstructed 180 degree field-of-veiw on the receiving end.


At least there is hope of a work-around for eye glass wearers. See your eye doctor for advice.


As for myself, I wear daily soft contacts and wash my eyes with Johnson's baby shampoo before insertion. Long term, this combination is very comfortable. Just as the doctor recommended too.
 

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If you put up a fine, perfectly converged white grid, some people will see perfectly converged.

Others with thick lenses, especially negative lenses, will see mis-converged red, green and blue lines.

The farther away they are from the screen, the worse it is.


Steve
 

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"Ever wonder why many motorcyclists prefer not to wear helmets in spite of the safety benefits provided?"


Yes I did and after doing a documentary on motorcyclists I had my answer.

90% said they love the freedom of feeling their hair blowing in the wind. 10% said they didn't like others telling them they had to wear a helmet if they decided to just choose to not wear one.


Not one motorcyclist ever stated:

"your images horizontal field-of-view (FOV) use the following equation:


FOV = 2*ArcTan(0.5*screen width/viewing distance)


Example: 8' horizontal screen being viewed at 12' the FOV is:

FOV = 2.0*ArcTan(0.5*8.0/12.0) = 36.87 degrees"
or any other BS similar to that.


:D



Can you edit your first post to dump or correct the ascii extended characters? None of that made sense.

"naming this (measurable) effect the “contrast ratio of the roomâ€.


"







Personally- I don't wear glasses so none of this applies to me. My wife does and she prefers to watch movies and anything in a darkened room with her contacts as it(according to her) reduces the distraction of glare especially driving at night. I'm sure a set of welding goggles with corrective lenses would work but she just prefers contacts.
 
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