I'm trying to understand the basics of 4:3 vs. 16:9 screens... Please read. - AVS Forum
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post #1 of 15 Old 08-09-2001, 04:14 AM - Thread Starter
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*NOTE* If any of my calculations are wrong (e.g., length x width, etc.), please let me know. *NOTE*

I'm trying to decide in between a 16:9 or 4:3 screen. I'm looking for a screen that is 92" wide. So, I believe my options are either:

A) a 52" (vertical/length) x 92" (horizontal/width) 16:9 screen; or

B) a 69" (vertical/length) x 92" (horizontal/width) 4:3 screen

I plan on watching primarily DVDs on it but will watch some television on it as well.

Since the width of the screen stays the same, whether 4:3 or 16:9, won't widescreen movies be the same size regardless of the aspect ratio of the screen? (Please answer this question!!!)

The only difference would be that, when watching widescreen material on a 4:3 screen, I would have excess screen space on top and bottom, no? Does this excess space have any downside (I keep hearing people talking about masking so I assume it's a big deal)?

Thanks everyone. I'm just a little confused right now.
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post #2 of 15 Old 08-09-2001, 08:03 AM
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Quote:
Since the width of the screen stays the same, whether 4:3 or 16:9, won't widescreen movies be the same size regardless of the aspect ratio of the screen? (Please answer this question!!!)
Short answer is yes, they will remain the same width.

Since you use a LT150 projector which has a native ratio of 4:3, then your best bet is to use a 4:3 screen. Your projector cannot place a 4:3 image in the middle of a 16:9 screen, so again a 4:3 screen is your best bet.

Quote:
The only difference would be that, when watching widescreen material on a 4:3 screen, I would have excess screen space on top and bottom, no? Does this excess space have any downside (I keep hearing people talking about masking so I assume it's a big deal)?
Yes, you will have some small unused space(letterbox bars) on your 4:3 screen when watching 1.85:1 DVDs and much larger letterbox bars when viewing 2.35:1 DVDs.

And regarding masking...once you have seen the benefits (especially with digital projectors) you will not want to live without it. The stray light makes the unused area above and below the image look gray and diminishes the image. Try using some black velvet or black velour in these areas and you will see a significant improvement in the image quality.

FWIW, I use a Stewart screen that has horizontal motorized masking for this exact reason. This screen is very expensive, but the results are stellar.

Enjoy,

DMan

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post #3 of 15 Old 08-09-2001, 12:59 PM
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But, using a $1400+ screen and a $2500 projector doesn't seem the norm. People normally spend much less ratio-wise on the screen than the projector.
Such as myself, 10HT for 5k, Stewart 100" Luxus Delux for $1200.

I plan on wathing only DVD's and HDTV and possibly some gaming on my system, it also has 16x9 panels so I bought the 16x9 screen. I just got the projector and straight out of the box, you really see the need for masking, but with my projector I can minimize the non-black areas with calibration. If the LT150 can be calibrated and tweaked, maybe the masking would not be a huge deal, since the masking is not cheap.

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post #4 of 15 Old 08-09-2001, 03:56 PM - Thread Starter
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DMAN:

Quote:
Short answer is yes, they will remain the same width.
What about length for widescreen movies? Both width and length, for widescreen material, will be the same size, no?

Quote:
Since you use a LT150 projector which has a native ratio of 4:3, then your best bet is to use a 4:3 screen. Your projector cannot place a 4:3 image in the middle of a 16:9 screen, so again a 4:3 screen is your best bet.
Some DVD players (RP91) and all scalers have the ability to center a 4:3 image on a 16:9 screen though, right?

SVonhof:

Given that you only watch 16:9 material, had you had a projector with only 4:3 panels, like the LT150, would you have bought a 4:3 screen? Or would you still have stuck to your 16:9 screen (with a 4:3 projector)?

Thanks guys!
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post #5 of 15 Old 08-09-2001, 08:15 PM
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Quote:
What about length for widescreen movies? Both width and length, for widescreen material, will be the same size, no?
A picture is worth a thousand words. Here's some examples of 4:3, 1.85:1, and 2.35:1 on a 4:3 screen.

http://www.thedigitalbits.com/articl...wizardofoz.jpg
4:3 image on 4:3 screen


http://www.thedigitalbits.com/articl...3tvlbx16x9.jpg
1.85:1 Widescreen image on 4:3 screen


http://www.thedigitalbits.com/articl...3tvlbx16x9.jpg
2.35:1 Widescreen image on 4:3 screen



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post #6 of 15 Old 08-09-2001, 08:17 PM - Thread Starter
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Dman: Thanks! Any chance you could do a similar listing of pictures w/ a 16:9 screen?
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post #7 of 15 Old 08-09-2001, 10:41 PM
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Ask and you will receive....

http://personal.atl.bellsouth.net/at...wizardofoz.jpg
4:3 image on a 16:9 screen


http://personal.atl.bellsouth.net/at...illhunting.jpg
1.85:1 image on a 16:9 screen


http://personal.atl.bellsouth.net/at...n/rushmore.jpg
2.35:1 image on a 16:9 screen



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post #8 of 15 Old 08-10-2001, 12:03 AM - Thread Starter
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Thanks Dman. Are these Photoshop pics?

Am I correct in concluding that:

If I get a 4:3 screen, I will have the ability to have a large 4:3 image and the same size 16:9 image as on a 16:9 screen but with black borders above and below the picture.

However, if I get a 16:9 screen, I will have a much smaller 4:3 image and the same size 16:9 image as on a 4:3 screen but without black borders above and below the picture (on 1.85:1 material).

Thanks!
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post #9 of 15 Old 08-10-2001, 07:18 AM
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Quote:
If I get a 4:3 screen, I will have the ability to have a large 4:3 image and the same size 16:9 image as on a 16:9 screen but with black borders above and below the picture.
Yes.

Quote:
However, if I get a 16:9 screen, I will have a much smaller 4:3 image and the same size 16:9 image as on a 4:3 screen but without black borders above and below the picture (on 1.85:1 material).
Yes.

One reason many people go with a 16:9 screen is because in a lot of setups, the ceiling height can get in the way. For example, if you only have enough wall height for a 54" high screen, would you select a 72"x54" 4:3 screen or a 96"x54" 16:9 screen? Also, since the highest resolution sources are HDTV and DVD which are both 16:9 formats, 16:9 screens make a lot of sense for most folks.

The main problem you run into with a projector like the LT150 is, if you use a 16:9 screen you will end up with 25% unused pixels when in 16:9 mode, which the projector will have to remain in. Here's a chart to see the pixel resolution used when using a 4:3 or 16:9 screen for the LT150.

4:3 screen
4:3 image= 1024x768
16:9 image= 1024x576
2.35:1 image= 1024x436

16:9 screen
4:3 image= 768x576
16:9 image= 1024x576
2.35:1 image= 1024x436




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post #10 of 15 Old 08-11-2001, 02:26 PM - Thread Starter
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Dman:

You mentioned that with a 16:9 screen, the LT150 would always have to be in 16:9 mode (thereby wasting 25% of the available pixels). Does this also apply to when watching 4:3 material on a 16:9 screen? Or just 16:9 material on a 16:9 screen? Thanks!
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post #11 of 15 Old 08-11-2001, 04:02 PM
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I realize that the LT150's bargain price might make spending big bucks on an anamorphic lens seem disproportionate, but it's one more idea to consider, I think.

With an anamorphic lens and an external scaler or HTPC to squeeze the input signal, you can take advantage of all of the 1024x768 DLP pixels for 16:9 images. 4:3 images will then use only 768x768 pixels. But since most of the material that is in 16:9 is higher resolution than the material that originates in 4:3, this seems like the right compromise to me.

In comparison to DMan's tables above:

Anamorphic lens with 16:9 screen (not square pixels)
4:3 image= 768x768
16:9 image= 1024x768
2.35:1 image= 1024x576

I understand that some anamorphic lenses may even be movable, so you could also get full resolution in 4:3, but I don't have experience with how tricky it is to remove and replace the lens.

I bought a CRT projector just days before learning of the LT150 deal at Dell. If I keep the LT150, I plan to spring for an anamorphic lens myself.

Edit:
One more thing to consider with an anamorphic lens is that the throw distance to image size relationship changes. For an ISCO style anamorphic lens, the width is increased 33% at a given throw distance. For a Panamorph II style lens, the height is decreased 33% at a given throw distance. This can be either a benefit or a curse, depending on your room.

-yogaman

[This message has been edited by yogaman (edited 08-11-2001).]
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post #12 of 15 Old 08-11-2001, 04:32 PM
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seems like i'm the only one with a new LT150 who wants his HT to be like a real theater
that means:
4:3 movies are smallest
16:9 movies are medium sized
and 2.35 movies are HUGE!

when i put in Gladiator, or Superman or Alien, i want it to be an epic-sized picture in relation to something like a pre-50's classic or TV show. those will still be big, but the widescreen movies will be enormous.

yes, you will have to physically move and re-orientate the projector everytime you change aspect ratios (unless, possibly if you have a panamorph), but honestly, is it that so difficult a procedure with a 3.3 lb device?
i'm a seriously lazy fellow, but i know if i spend a few hours doing dry runs, taking measurements, building a box that can acommodate 3 different fixed heights...i will have a streamlined system in place for accomplishing this.
why everybody doesn't want to go fixed height/variable width...especially with a mobile prestentation projector like this one, is a head scratcher to me.
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post #13 of 15 Old 08-11-2001, 06:20 PM
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Ckolchak:

I admire your reasoning. I like the fixed-height idea.

Unfortunately, though, your suggestion to move the projector doesn't do anything to prevent you from getting the lowest resolution on the biggest image.

So, inserting tongue partway into cheek, I propose that you could get full resolution on every image size by using 0, 1 or 2 ISCO-style anamorphic lenses for 4:3, 16:9, or 64:27 (2.35:1), respectively. (This assumes it's not too difficult to remove and replace anamorphic lenses, and that the refocusing required is not too troublesome.)

The major drawback to anamorphic lenses is that the suggested retail price for each ISCO-II is more than the Dell LT150 price.

One other drawback to constant height is that the biggest image will be the dimmest image. I don't see any easy way around this, but at least the anamorphic lens(es) approach prevents a double loss due the larger image compounded by the reduced DMD area.

(OK, one easy way to even out the brightness would be to also insert one or two 33% neutral density filters in the optical path for 16:9 or 4:3, respectively. Another would be to scale the video signal with your HTPC so that only 3/4 of the maximum light is used for 16:9 and only 9/16 of the maximum light is used for 4:3. But I consider throwing away light like this to be a sin against nature.)

Still, I like your fixed height idea. I'm going to have to think more about this.
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post #14 of 15 Old 08-11-2001, 06:58 PM
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i would love to use an ISCO or panamorph, but price is the prohibitive in my current fiscal situation.

as far as dimness goes- i'm already doing the CH/VW, albeit a little half-a$$ed. i've taken some measurements and will build the variable height box as soon as i get the chance.
yes, i would say 4:3 movies seem a bit brighter, but
i haven't really noticed THAT much of the dimming of the pic. or rather, i'm not conscious of it being that much of a detriment to my enjoying the pic.
usually, to help with placement i set the 4:3 to native, and the 2.35 to auto.
as far as resolution goes-at the moment i cna't really evaluate this well enough. with my s-vid connection, i think i have other PQ concerns http://www.avsforum.com/ubb/wink.gif.
i know a dim picture on the widescreen stuff, isn't one of them at this point.
most people here have far more experience with projectors than i do so i'm sure for this MMV, but for me this doesn't seem to be a problem.

[This message has been edited by ckolchak (edited 08-11-2001).]
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post #15 of 15 Old 08-12-2001, 09:55 PM
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Quote:
You mentioned that with a 16:9 screen, the LT150 would always have to be in 16:9 mode (thereby wasting 25% of the available pixels). Does this also apply to when watching 4:3 material on a 16:9 screen? Or just 16:9 material on a 16:9 screen? Thanks!
Putting the anamorphic lens issue aside for the moment, to use a 16:9 screen with the LT150, yes you will have to leave the projector in 16:9 mode. I think they refer to it as "Cinema" mode. Then, the only way to get a 4:3 image inside the 16:9 area is to use a video processor that has this function or a HTPC.

An anamorphic lens does allow you to use the entire 4:3 panel with a 16:9 screen because the lens stretches the image to fit a 16:9 screen. Again, a video processor or HTPC will need to be employed here as well to use the anamorphic lens.



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