AVS Forum banner
Status
Not open for further replies.
1 - 17 of 17 Posts

·
Registered
Joined
·
131 Posts
Discussion Starter · #1 ·
OK, follow my reasoning on this and see if it makes sense:


If I want to maintain a picture 48 inches high, a movie with aspect 1.78:1 will require a width of 85.3 inches, and a movie with aspect 2.35:1 will require a width of 112.8 inches.


Based on the data posted at http://www.thebigpicturedvd.com/dcfo...mID53/28.shtml , if I set a Sanyo PLV-60 projector at a distance of 14.5 feet from the screen, it will zoom the width over a range of 84.9 to 112.3 inches. Pretty close!


So, at this projector setting with a 48 inch high 2.35:1 aspect screen, it looks like I can watch 1.78:1 movies at the minimum zoom (with no black bars at the top...straight 16:9), and then watch 2.35:1 movies by zooming the lens to the max and eliminating the black bars on the top and bottom. Doesn't sound like I need any special lens.


Does this sound right? Can any PLV-60 owners confirm this data? The ability to zoom between 1.78:1 and 2.35:1 without a special lens would be a great feature of this projector.


P.S. I know the zoom will make the screen door effect worse, but I'm planning on using a Cygnus IMX to compensate for that.
 

·
Premium Member
Joined
·
25,537 Posts
Be aware that the 16:9 image will be 1.75X brighter than the 2.35:1 image. This could be recovered by using a Panamorph and the full-screen option on the PLV60.


------------------

Noah


[This message has been edited by noah katz (edited 06-13-2001).]
 

·
Registered
Joined
·
131 Posts
Discussion Starter · #4 ·
OK, maybe I'm too new at this stuff to understand, but why would the Panamorph lens retain the brightness where as the built-in zoom lens would not?? It seems like the brightness should be related to the size of the picture and if both solutions are producing the same size 2.35:1 aspect with a height of 48 inches, then the brightness should be the same. Is the Panamorph doing some sort of magic that I'm not aware of (their IMX *is* magic, so maybe their Pamamorph is to?)
 

·
Registered
Joined
·
26 Posts
If there is a difference in brightness, the PLV-60 would be easy to adjust as it allows the storing of four user-defined image types saved brightness, etc. settings. They can be toggled by pressing the Image button on the remote.

 

·
Registered
Joined
·
6,225 Posts
The brightness difference results from the number of pixels being used to transmit light versus the number which are blacked out above and below the 2.35:1 picture when it is zoomed. Much of the projection lamp output is turning into wasted heat on these letterbox bars. This is true whether the bars are present in the DVD, or the DVD player has inserted them, or the projector has added them (the last two being possible with anamorphic DVDs).


In addition to the brightness differences, which at 1.75:1 are probably of such significance that it would be impossible to optimize all the projector settings for both modes (but for which satisfactory compromise settings could probably be found), you would also of course have the reduced resolution to go with the zoom mode, because you are only using the center of the LCD panel.


These considerations are the same for all digital projectors, and matter more for some than others. Most 4:3 XGA projectors with power zoom can be adjusted to produce very reasonable screen-filling pictures at 1.78:1 and 1.85:1 aspect ratios, but few can be zoomed all the way to fill a 2.35:1 screen without visible degradation.


I'm guessing you've done the math correctly, and that 2:35:1 zoom mode on a true 16:9 projector panel may be as acceptable to most folks as are the common zooms mentioned above for the 4:3 projectors.


There will always be those who want the extra performance brought along by the addition of the Panamorph and ISCO widescreen lenses, and who are willing to pay for it.


I rent DVDs, and so many are in 2:35:1 aspect ratio that I would love to purchase a projector with that aspect ratio panel at say 1920X768 resolution, and display the other aspect ratios (1.33:1, 1.78:1. 1.85:1) digitally within that panel (1.33:1 = XGA or 1024X768, etc.). Such a display would do justice to 1080i HDTV as well, since most 1080i sources constrain horizontal resolution to 1280 pixels or so, which would be scaled and line doubled and displayed at 1360X768 for the 1.77:1 aspect ratio.


That way, the only time I would ever see letterbox bars is very wide aspect ratios such as the Ben Hur DVD with it's 2.76:1 aspect ratio, which was fairly ridiculous on my 4:3 display. Talk about huge black bars....


Gary
 

·
Registered
Joined
·
131 Posts
Discussion Starter · #7 ·
OK, so let me see if I have this right:


Loss of brightness due to fewer pixels: 2.35:1 image has 1.32 times fewer pixels than 1.78:1 image.


Loss of brightness due to increased screen area: 2.35:1 image is 1.32 times larger in area than 1.78:1 image.


So, total brightness loss is 1.32*1.32 = 1.75 (roughly). So that all makes sense now.


Maybe it's good that I'm planning to upgrade to the PLV-60 from such a crummy current setup. My current projector is only 800x600, and only 800 lumens. Since the PLV-60 is 1400 lumens, the decrease in brightness from the zooming just means it will be a similar brightness to what I'm already used to, but on a 112 inch wide screen instead of a 64 inch screen (the current width of my current 4:3 screen). Sounds like I'll still be blown away by the zoomed 2.35:1 picture!


The loss of resolution is another good point. Zooming the projector to make the 2.35:1 image full screen increases both the vertical and horizontal pixel size, thus reducing the resolution. The number of pixels vertically will go from 768 (native 16:9 mode), to 580 or so. In other words, it will have a similar resolution to my current 800x600 projector. On my current project I use an IMX lens to get rid of the screen door effect. Since zooming retains the square pixel shape, I should still be able to use my IMX lens to remove the screen door effect on the zoomed image.


In fact, if you use a Panamorph lens to stretch the pixels horizontally and not vertically, you end up with rectangular pixels, and I'd wonder if the IMX lens would work with that. Seems like with the Panamorph you are still losing resolution, but only in one direction. This might be better, but if you can't fix the screen door effect with a piggy-back IMX lens (can you mount them together?) it might end up being a worse solution in the long run.


I guess I'll just have to buy this PLV-60 and set it up and do the zooming test to see what it is really like. It still sounds to me like an ideal projector for maintaining constant screen height movies. But only a live demo will prove whether this is the case.
 

·
Registered
Joined
·
304 Posts
can a plv-60 owner confirm that the projector can indeed fill the ENTIRE 16x9 LCD panel with a 2.35 image (thus enabling use of ISCO lens to project 100% of the pixels onto a 2.35 screen)


what is this command called in the manual?


can the 2.35 vertical stretch option be used on ALL 2.35 DVD material (anamorphic AND non-anmorphic)?


thks!
 

·
Registered
Joined
·
4,580 Posts
I have been following the 2.35:1 to anamorphic 1.78:1 saga for a few weeks. I think it is very, very strange that the software engineers at Sanyo would include a 2.35:1 to anamorphic 1.78:1 option in the menu. The reason being that it serves absolutely no purpose whatsoever - unless you are using an anamorphic lens - in which case it is a godsend. I wish someone would pop in the Avia DVD and select the overscan pattern, apply this anamorphization step and check for horizontal overscan. It's possible that what we really have here is just a zooming option which is de rigeur for many 16:9 TV's. This will be made crystal clear with Avia. If you don't have the Avia disc, I think it's worth the investment. I have used it more times than I can count. Good luck and kudos to Sanyo - if they really had the foresight to include an anamorphic lens option in their scaling software.


[This message has been edited by Larry Davis (edited 06-15-2001).]
 

·
Registered
Joined
·
423 Posts
Even in the absence of a test disk, you should be able to tell. If it's a 2.35 anamorphic option, the image will be stretched. If it's simply a zoom, it will fill the screen, but be properly proportioned. The horizontal borders of the picture will also be cropped.

 

·
Registered
Joined
·
4,580 Posts
Yes Doc, you and I could eyeball it and know immediately if the unit did what has been claimed. But sometimes well meaning people make mistakes and the AVIA disc would settle things conclusively.
 

·
Registered
Joined
·
423 Posts
It does sound too good to be true. Hope it pans out.

BTW, I'm going to immediately get the disk to check out the overscan I've noted on my VT540's video inputs. Thanks.


[This message has been edited by drmyeyes (edited 06-17-2001).]
 

·
Registered
Joined
·
304 Posts


any sanyo plv-60 owner out there want to settle this for once & all?


also please let us know if the 2.35 vertical stretch option be used on ALL 2.35 DVD material (anamorphic AND non-anmorphic)
 

·
Registered
Joined
·
111 Posts
Bossmonkey,


I have had my PLV-60 for about a week now. I have not been able to find anything that will cause any 2.35:1 movie, anamorphic or not, to fill the full 16:9 panel.


The video mode aspect options are the typical ones: full (make anamorphic fill the screen), zoom (scale non-anamophic letterbox to fit the width of the screen while maintaining its aspect), normal (4:3 full hight, proper aspect), and wide-zoom (for 4:3, stretched horizontally to fill the screen).


The computer mode aspect options are normal and full (as above), true (1:1 pixel mapping), and digital zoom.


Optical zooming appears the only way to get a 2:35 image to match the height of a 1.86, and then only if the pj is exactly the right distance from the screen.


Not the answer you wanted to hear...


Frank L
 

·
Registered
Joined
·
2,767 Posts
I don't have my PLV-60 anymore, but I know I did it on mine when I had it. And I checked it three times on Gladiator, just to make sure I wasn't seeing things. It did not change the width of the picture, which already filled the screen width and did not cut off anything from the sides of the image, but it stretched it so the the characters became tall and skinny and the picture then filled the whole screen with no black bars. Since I don't have the unit anymore, I can't repeat it, but I know others have reported being able to do it (on the The Big Picture Forum I think).
 

·
Registered
Joined
·
2,314 Posts
If my memory is right (too lazy to go turn it on right now), my Sony 10HT does the same thing Smitty described. It simply stretches the 2.35 image from top to bottom to fill the whole 16:9 screen. Nothing gets cropped on either side, but the fat people look trim, and the skinny people look anorexic.


------------------

Steve

Visit our dedicated home theater, The City Cinema.
 

·
Registered
Joined
·
111 Posts
Bossmonkey,


Smitty remembers correctly. My earlier post in this thread was partially incorrect. The zoom command vertically stretches 2.35 anamorphic movies to fill the screen without any additional horizontal stretch. An ISCO or Panamorph should work properly in this case.


However, on letterboxed 2.35 (non-anamorphic) material the zoom command maintained correct aspect ratio - there are black bars top and bottom. Can't use the lens here.


Frank L
 
1 - 17 of 17 Posts
Status
Not open for further replies.
Top