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post #1 of 24 Old 10-10-2011, 08:04 AM - Thread Starter
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Sorry if this is a basic question, but I'm trying to figure out what is (or is not) projected on a CIH screen.

Projectors like the PT-AE7000 (auto selection) and RS45 (manual selection), have lens memory that makes a CIH set up easy. (If there are any other projectors in this price range that does this, please let me know.)

I'm guessing when projecting a 16x9 format, the sides of the 2.4:1 screen is unused. The ends are ideally masked off.

When the format is 2.4:1, the projector zooms wide (zooms in?) and the 2.4:1 image fills the screen. My question is what is "projected" above and below the image in this case? Is there literally nothing projected above and below, or is there still the black bars like you would normally get on a non-CIH set up?

Thanks in advance for helping me understand.
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post #2 of 24 Old 10-10-2011, 08:25 AM
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The black bars are simply zoomed off the screen. That's why a black screen border wide enough to absorb the black bars is recommended.

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post #3 of 24 Old 10-10-2011, 08:42 AM - Thread Starter
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Quote:
Originally Posted by petew View Post

The black bars are simply zoomed off the screen. That's why a black screen border wide enough to absorb the black bars is recommended.

I think this is discouraging. Typical borders (if not DIY) are not much more that 3". Wouldn't the zoomed off portion typically be beyond 3" (lets' say a 103" 2:4:1 screen)? ...so the portion of the image above and below the screen must be projection on a light absorbing surface?
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post #4 of 24 Old 10-10-2011, 08:49 AM - Thread Starter
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See this projection here. It is from the AE7000 thread and I don't believe it uses an A-lens to achieve the aspect ratio.

http://www.avsforum.com/avs-vb/showp...&postcount=201



I do not see any projection above or below the image. Is the portion above and below the image so dark that it isn't much of an issue?
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post #5 of 24 Old 10-10-2011, 09:20 AM
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Quote:
Originally Posted by Liaury View Post

I think this is discouraging. Typical borders (if not DIY) are not much more that 3". Wouldn't the zoomed off portion typically be beyond 3" (lets' say a 103" 2:4:1 screen)? ...so the portion of the image above and below the screen must be projection on a light absorbing surface?

The Panny 7000 also has a masking feature that you can use to "turn off" the unused pixels so that it will not project anything in the outside area.
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post #6 of 24 Old 10-10-2011, 09:24 AM - Thread Starter
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Quote:
Originally Posted by Killroy View Post

The Panny 7000 also has a masking feature that you can use to "turn off" the unused pixels so that it will not project anything in the outside area.

Is it know if the JVC RS45 has this feature? If not, ...well that pretty much makes my projector choice down to one.
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post #7 of 24 Old 10-10-2011, 09:34 AM
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Quote:
Originally Posted by Liaury View Post

Is it know if the JVC RS45 has this feature? If not, ...well that pretty much makes my projector choice down to one.

I want to know too so I am patiently waiting for JVC to release the user's manual to see if it's there.
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post #8 of 24 Old 10-10-2011, 09:36 AM
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Quote:
Originally Posted by Liaury View Post

I think this is discouraging. Typical borders (if not DIY) are not much more that 3". Wouldn't the zoomed off portion typically be beyond 3" (lets' say a 103" 2:4:1 screen)? ...so the portion of the image above and below the screen must be projection on a light absorbing surface?

True, the darker the screen wall the better. Until I added an A-lens I was zooming. But the screen wall is the same fabric (triple velvet) as the screen frame itself. And the proj, (a JVC) is very good at projecting black (bars in this case), making the spillover bars virtually if not entirely unnoticeable. (This model JVC (HD-950) does not have the masking feature. Can't say about their latest line.)
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post #9 of 24 Old 10-10-2011, 09:51 AM
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I have masking about 6" in front of my projector lens which blocks the light spill beyond the screen border.

Look at the projector in this shot:


The black bands in front of the lens works well to block light above and below the screen border. It's obviously not a sharply defined edge but it works. I used steel strips covered in velvet, stuck with magnets to the projector frame.

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post #10 of 24 Old 10-10-2011, 09:52 AM
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Quote:
Originally Posted by Liaury View Post

Is it know if the JVC RS45 has this feature? If not, ...well that pretty much makes my projector choice down to one.

I have the RS40, and it does not have this feature. I imagine that the RS45 is the same. It's a very unusual feature.

Some dark velvet or velveteen masking material above and below the screen will do a very good job of absorbing the black letterbox bars so that you don't notice them.

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post #11 of 24 Old 10-10-2011, 10:04 AM - Thread Starter
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Quote:
Originally Posted by Josh Z View Post

I have the RS40, and it does not have this feature. I imagine that the RS45 is the same. It's a very unusual feature.

Some dark velvet or velveteen masking material above and below the screen will do a very good job of absorbing the black letterbox bars so that you don't notice them.

I'm planning to place a center channel speaker (has piano black surface) as close to the top edge of the screen as possible (no room for behind the screen), so anything projected would not be good. Petew's idea would work, but that would require some ingenuity for a ceiling mount. I suppose I could just place two strips of electrical tape in front of the lens.
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post #12 of 24 Old 10-10-2011, 12:04 PM
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Please note that the masking feature in the Panasonic projectors is only electronic: This will switch off unwanted parts of the image, but you are still passing lamp light through the panel, so it's no darker than the 'black bars' would be from a 2.35:1 disc. However, this needn't be an issue with either the RS45 or AE7000 unless your screen surround is very light as when I had the older AE3000 and zoomed, by dark brown screen wall didn't 'show' the black bars...only my original AE1000 did this, even then only slightly.

Put it this way, I wouldn't use it as a decision making item.

Zooming: Been there, done that, bought the lens...
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post #13 of 24 Old 10-10-2011, 01:27 PM - Thread Starter
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Thanks for all the knowledge dropped in this thread.

I'm arriving to the final conclusion that the spillover (black bars) is essentially no light. (at least from the two projectors mentioned)
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post #14 of 24 Old 10-10-2011, 01:51 PM
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Quote:
Originally Posted by Liaury View Post

I'm arriving to the final conclusion that the spillover (black bars) is essentially no light. (at least from the two projectors mentioned)

I don't have experience with the Panasonic models, but from what Kelvin says, they appear to work the same as pretty much any other digital projector. The entire 16:9 pixel panel is being projected at all times. There is no way to "shut off" specific pixels. What the Panasonics offer is the ability to electronically mask the top and bottom of the image, so that those parts of the frame project black, which is no different than the black letterbox bars. This is really only useful if you want to take a 16:9 picture that doesn't have letterboxing and add letterboxing to it.

Light will always be projected above and below your 2.35:1 screen unless you add an anamorphic lens.

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post #15 of 24 Old 10-10-2011, 02:02 PM - Thread Starter
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Quote:
Originally Posted by Josh Z View Post

This is really only useful if you want to take a 16:9 picture that doesn't have letterboxing and add letterboxing to it.

No way any of us is doing that. Then you'll lose film from the sides and top/bottom. You'd probably only get ~50% of the original image.
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post #16 of 24 Old 10-10-2011, 02:38 PM
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It's also useful for films like Transformers 2 or The Dark Knight, who's aspect ratio changes in the middle of the film.

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Originally Posted by Liaury View Post

No way any of us is doing that. Then you'll lose film from the sides and top/bottom. You'd probably only get ~50% of the original image.

You would not lose anything off the sides, just the 25% from the top/bottom. Not saying I condone that...

See what an anamorphoscopic lens can do, see movies the way they were meant to be seen
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post #17 of 24 Old 10-11-2011, 07:33 AM
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Quote:
Originally Posted by stanger89 View Post

It's also useful for films like Transformers 2 or The Dark Knight, who's aspect ratio changes in the middle of the film.

And for movies that were originally composed for 2.35:1 but transferred to video "open matte" with excess picture at the top and bottom, like Avatar.

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post #18 of 24 Old 10-11-2011, 08:08 AM - Thread Starter
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Originally Posted by stanger89 View Post

You would not lose anything off the sides, just the 25% from the top/bottom. Not saying I condone that...

"Loosing from the sides" meaning when they cropped of the ends of the film to fit it on a 16x9 disk.
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post #19 of 24 Old 02-06-2012, 01:37 PM
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I just can't believe no manufacturer has come up with a Projector that can completely shut off the pixels corresponding to the black bars, and eliminate all light from the source, for perfect pitch black bars.

If the man made it to the moon 40 years ago, SURELY properly masking the pixels must be possible. I am not taking no for an answer!

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post #20 of 24 Old 02-06-2012, 01:52 PM
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Quote:
Originally Posted by gnolivos View Post

I just can't believe no manufacturer has come up with a Projector that can completely shut off the pixels corresponding to the black bars, and eliminate all light from the source, for perfect pitch black bars.

Because you can't, the pixels don't emit light, they simply pass or block it, and it's impossible to block 100% of light. Think of it like an LCD display with a single backlight, you can't turn off part of the backlight, the whole thing is either on or off.

What has been done is several LED DLPs can turn off the light source completely for black screens. And for a while there was talk of local dimming for LED DLPs (many LEDs to light small areas, but not individual pixels), but that talk seems to have stopped, probably ran into overwhelming technical challenges (unless some company wants to release one and prove me wrong )

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post #21 of 24 Old 02-06-2012, 03:23 PM
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I understand you cant black out pixels with CURRENT technology. Still, surely you can mechanically block the light path at the source, before the light hits the LCD panel? im thinking, something like a mask top/bottom between the light and the panel. Complete obstruction of light path.

Anyhow, a true solution may require complete rewrite of the current LCD/light design. Im OK with that.

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post #22 of 24 Old 02-06-2012, 07:09 PM
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Quote:
Originally Posted by gnolivos View Post

I understand you cant black out pixels with CURRENT technology. Still, surely you can mechanically block the light path at the source, before the light hits the LCD panel? im thinking, something like a mask top/bottom between the light and the panel. Complete obstruction of light path.

Anyhow, a true solution may require complete rewrite of the current LCD/light design. Im OK with that.

This is basically, what stanger89 was eluding too. Even for LCD, local LED light control is possible for zone or even for individual pixels. I'm sure it would be more expensive, as you have to address each of the LED's associated with its own LCD pixel. That would totally block light at the pixel level, except for maybe some bleed-over from adjacent "ON" pixels. For individual control that would double the opportunity count for a failed pixel, as seen on screen, as a failed pixel can be attributed to the LCD element or the LED or both.

Mechanically block the light........wow! I guess you can direct the light into the LCD pixel with a DLP element........basically, a mirror on a hinge........the digital micro mirror. Now that would be a mechanical nightmare!
Talk about opportunity counts! Why not just eliminate the LCD part of the equation and just get a DLP.
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post #23 of 24 Old 02-07-2012, 03:35 AM
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Is that essentially what DLP does then?

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Mechanically block the light........wow! I guess you can direct the light into the LCD pixel with a DLP element........basically, a mirror on a hinge........the digital micro mirror.


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post #24 of 24 Old 02-07-2012, 07:24 PM
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Quote:
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Is that essentially what DLP does then?

Yep..........only Rube Goldberg like!
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