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Peter,


Just wanted to say thanks for your contributions to the projector forums here.


Your photos, graphs, etc. have really been insightful, even to a trigonometry challenged person like myself.
 

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nice find Peter
 

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Thank you Peter- I had an idea of these numbers, but it is very nice to see it all laid out in a concrete format. This should prove useful on future projects-
 

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Discussion Starter · #28 ·
I did think this thread could be fixed. Because these standards are not old. But I'm not a moderator to decide about it.


I'll be watching this thread and I'll trying to help as much as I can.


Peter
 

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This often comes up here and other places, and this diagram gives a good idea of what viewing angles certain seating distances will give:




Using image height is preferable to diagonal measurements since they're a lot easier to work with, and removes confusion with screen aspect ratio - many people here have 2.35 screens and using the height works for 16:9 and 2.35 when using an A lens.


THXs recommended viewing angle for HD 16:9 screens is 40 degrees, or 2.4 image heights. That also works for people with 2.35 screens who use an anamorphic lens, and may work with some pjs that zoom for scope. Sitting at 2.4 SH for 16:9 is 40 degrees and 52 degrees for 2.35 from the same seat.


The film industry used to recommend 3 x IH for seating distance based on the crossover point between immersion (closer is considered better) and where image artefacts like film grain and projector induced issues become visible. With digital and good HD content that limitation is reduced, and is probably why THX recommend 2.4 x IH (52 degrees) rather than 3 X IH. Sitting anywhere between 2 to 4 times the Image Height puts you within the usual range of a commercial theatre, and with 1080 displays, we're pretty much there with regards to resolution and image quality.


As Darin has pointed out, THX often gets misquoted so this video may be of interest:

http://www.youtube.com/watch?v=rBdmG...embedded#at=50


I also think it's worth pointing out that the graphs that say where certain resolutions become noticeable doesn't mean you should sit there. In fact you should probably sit closer because those distances are where the Human eye can start to resolve those resolutions, so sitting closer means those resolutions become more visible and detail visibly clearer. If you sit at the threshold of visibility of lets say 1080 and then comparing it to 720 from the same distance (all else being equal), you might not be able to tell the difference between the two until you get much closer.


Gary
 
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Discussion Starter · #30 ·
I really appreciated your post (contribution) to this thread.


I'll quote your post in the first page.


Thank you,


Peter
 

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Peter,


Thanks for all the great information. You need to convince the moderators to make this a sticky thread.


Cheers,

Scott
 

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These charts and tables for good starting points, but viewing distance is a very personal thing, with wide variation in preferences. E.g., with a 2.35 screen I have seen many people report liking to sit ~ 1 screen width away ((53 deg viewing angle). This is a bit too close for me; I sit ~ 12.5 ft from a 12 ft W 2.35 pic (51 deg angle). For a 16x9 pic, from this same viewing distance, my viewing angle is 46 deg, which I fine good. I.e., I like a very immersive pic, but others fine it better with smaller viewing angles.


And I agree with Darin, that viewing angle [2*arctan(.5/SW), where SW is the viewing distance divided by the screen width] is the more useful parameter to discuss.
 

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Discussion Starter · #35 ·

Quote:
Originally Posted by audionewer /forum/post/21882662


i am wondering which standard i shall go with? THX or SMPTE?

These standards help to start, but can not be used as definitive.


Make some tests with a white cloth, so you can increase or decrease the size of the image until you find the right size for you and your family.




Best regards,

Peter
 

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i got 100inches 1.3 gain screen. i have to shrink it a little bit ( 92inches). i sit about 11 ft from the screen right now. i hope that is okay.
 

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Discussion Starter · #37 ·

Quote:
Originally Posted by audionewer /forum/post/21883073


i got 100inches 1.3 gain screen. i have to shrink it a little bit ( 92inches). i sit about 11 ft from the screen right now. i hope that is okay.

I think it is ok.

it is inside the SMPTE Standard.

I prefer the SMPTE instead of THX.
 

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Bump with new info:

I was posting in this thread, Will I See Pixels? , and saw new chart with 4k added to Carlton Bale website.

Saw it was not in this thread, the "old" 1440p was posted, so posted here as well.
Quote:
Originally Posted by mtbdudex  /t/1433660/will-i-see-pixels#post_22489661


There is also this chart, when I was designing my home theater it was helpful, I overlaid my viewing distance on LH axis and intended screen size bottom axis.

Then you know what zone you fall into.

(yea, being an engineer we do this daily)


More info here Chart Distance x Screen Size - Standards SMPTE and THX



Ok; it's been so long since I used it (2007), I see chart has been updated for 4k, cool.
http://carltonbale.com/
 

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Quote:
Originally Posted by Peter_  /t/1004723/chart-distance-x-screen-size-standards-smpte-and-thx/30#post_22489777


Thank you, Mike.


Excellent Addition.
I try to point people to the info/data so they can grasp the "why things are they way they are" and reach their own conclusions instead of just telling them.

Your thread is a perfect example of that, give info and let them grasp.


Side note1;for those who took thermodynamics, remember your charts/tables used to explain the state of matter? (solid-liquid-gas)


and Pressure vs volume (lines of constant temp) ......or Temp vs Volume?(lines of constant pressure)



Now those took a while to use proficiently.....


Side note2: What is the only element that crystallizes from the top > down?

And why is that so important?
 
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