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Discussion Starter · #1 ·
Has anyone used the combination above? How did it work?


I know the lens costs as much as the projector but some folks go through projectors and lenses like I do peanut butter and jelly. http://www.avsforum.com/ubb/smile.gif I was thinking someone may have or have had the two together at the same time.


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Huck
 

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I have this combination and must say it does add pincusion distortion to the image. However I find that the increase in brightness and detailhas been a reasonable trade off to me.


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John
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Discussion Starter · #3 ·
Thanks for your quick response. Can you quantify the distortion? For example, how wide is your image at the top vs the middle? Thanks.


EDIT: I just saw your post to the Panamorph distortion thread. I'll follow that one for the images. Thanks.


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Huck


[This message has been edited by Huckster (edited 08-28-2001).]
 

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The sides seem to be fine. The image is bowed in on the top and the bottom about an inch to an inch and a half. I promised on another thread to post some pictures using a test pattern, so tomorrow I should have some results for you to see.


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John
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Grant,


The distortion is noticable, but I can ignore it when I get into a movie. As I mentioned in another post, I'm not sure I have the optimum alignment of either the projector or the ISCO so I am still trying different positions.


I have a Faroudja DVP 2200 I'm using for deinterlacing. The DVP outputs either a 480p or 600p signal. I was using 480p component before the ISCO. When I received the ISCO I was able to use the 600p RGB and go back and forth. I think the 600p shows more detail with the ISCO than the 480p without. And definitely 1024 x 576 is softer than 1024 x 768.




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John
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I'm using the ISCO II with a 104" wide 2.35:1 screen. For 16x9 I'm watching 80" wide.


I'm a stickler for really sharp, straight borders, and I would find it really annoying to see pincushion (ISCO) or barrel (Panamorph) distortion while watching a movie.


The solution is proper masking either applied to the screen or hung around it. Enlarge the image just until the curved edges of the image fall totally within the masking. The result is "perfect". The lens is well worth it.
 

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Quote:
Originally posted by drmyeyes:


The solution is proper masking either applied to the screen or hung around it. Enlarge the image just until the curved edges of the image fall totally within the masking. The result is "perfect". The lens is well worth it.
Until you have a straight line near the boarder.




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Greg
 

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That's why I wrote "perfect".

However, this doesn't happen very often, is transient when it does, and is minor, whereas without masking the minor pincushion is always there, becoming major.

You won't be unhappy unless you're really even more obsessive than most of us.
 

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Wireless, how noticeable is the distortion (I'll look at the pics, however, real life is better). I know someone with this combination and he just sold the ISCO II and told me about the distortion and said the picture was too soft. You say there's added detail and he says it's too soft. Does it soften the image from your perspective?


The Panamorph with any projector with a throw angle seems like a problem - why haven't the powers to be tried some of these combinations - at least projectors that represent a group with similar throw angles etc.?


Thanks for any help.


Cheers,


Grant
 

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Discussion Starter · #11 ·
Drmyeyes - On your 80" wide image, how large is the effect? 1" on the top and bottom? More? Less? Thanks.


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Huck
 

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I'm using a 92" wide screen.


I had to rehang my screen last night and realign the projector and ISCO.


Sorry for the delay but it will be tommorrow before I can post some picts.


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John
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Huck-

About 1" total, maybe a smidge more, divided between top and bottom, when watching 16x9 at 80" wide. I'll measure next time I watch a disc (not tonight, maybe tomorrow).

(i.e.- the center of the image is 1" narrower than the edges)

I just enlarge the image enough so that the center fills the height of the screen, and the edges overshoot a bit onto the masking surrounding the active picture area (masking is part of my screen), producing a straight edge. I mask the sides with curtains. (I've glued a metal strip to the leading edge of the curtains to keep it straight and sharp.)

Only once in the past several months did I run into the situation where a projected horizontal straight line, part of the movie titles, near the border of the screen, was visibly curved, noticeable mostly when I froze the image. That was also mostly because I had everything set up out of wack. By fine tuning the projector and ISCO angle, any distortion is really not visible when watching movies, as long as the edges are masked. And, yes, I am obsessive-compulsive about these things, but I guess that's relative.


[This message has been edited by drmyeyes (edited 08-29-2001).]
 

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How about when watching a 2.35:1 dvd. Are the black bars distorted?


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Greg
 

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Discussion Starter · #15 ·
I'm having a hard time waiting for those pictures. http://www.avsforum.com/ubb/wink.gif Patience is not one of my strong attributes.


Is the distortion uniform (geometrically increasing?) across the image (middle to top/bottom) or is there a point where it distinctly starts (1/2 from middle to top/bottom, for example). The question about 2.35:1 AR movies got me thinking the distortion, if uniform, would be much less for wider aspect ratio movies. I would expect it to be more noticeable when using a 16:9 screen and displaying a 1.85:1 movie. Those thin black bars at the edges might pose a problem. Of course, you would probably overscan to put the bars into the masking.


On a completely different topic: Is the lens easy to remove when using the supplied mount? From reading the literature, it stretches ONLY in the horizontal plane so I would expect the 4:3 image to be perfectly centered on a 16:9 screen when the ISCO II was removed.


Sorry for pestering you. I'm just really interested. Thanks.


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Huck
 

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Huck,


I started a new thread and posted some picts of the ISCO II & LT150.


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John
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Greg-

I'm using a 2.35:1 screen, projecting everything at constant height, variable width, so horizontal black bands and pincushion effects are masked off, beyond the active picture area, on all material, with no visible distortion. Otherwise, yes, letterboxed 2.35:1 would show pincushion distortion, and I would be unhappy.


BTW- would a curved screen correct this?
 

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drmyeyes,


I think a horizontally curved screen would help. The curve in at the centre would increase the throw and that would counteract the pincushion. If would take a little work to figure out the radius you would need... I also seem to remember some people commenting on difficulties focusing the ISCO, a curved screen would probably also help.


Regards,


Kam Fung
 

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Discussion Starter · #19 ·
I thought the LT150 has a lens that is designed for flat screens. A curved screen would remove the possibility of focusing the image, wouldn't it? Or are you saying in your last sentence that the current distorted image is also out of focus (edge to edge) because it needs to be on a curved screen?


EDIT: clarified my question (I think).


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Huck


[This message has been edited by Huckster (edited 09-01-2001).]
 
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