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Finished my DIY curved screen set-up with pics

78K views 84 replies 35 participants last post by  John van Ommen 
#1 ·
First of all I would like to thank everyone on this thread who helped answer all of my questions to make my set-up possible. My main concern was would 2:35 work on my short throw set-up ( just under 10 ft from screen to lens, 45" height with a throw ratio of 1.47) and in my case, yes it will work. I wound up buying the Panamorph 380 lens and the Sony vpl vw60. After talking to Panamorph they said the lens will work with my short throw however I will get some pincushioning which is why I built the curved screen. I also built a manual sled from ideas I also got from you guys. I wound up covering the screen with black velvet material with self adhesive that I got from Mcmaster-Carr Supply, the stuff works great. Enclosed are some pics. Anyone thinking of going 2:35, GO FOR IT !!! the effect is unbeliveble. In the future I want to add remote control curtains for masking and maybe build a remote control transport for the lens, I used to hate 2:35 movies, now it's all I want to watch. Thanks again for all your help,

George



 
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#28 ·
So if you know your screen size, throw distance, projector, and lens make/model, is there any way to determine the pincushion correction prior to actually putting the theater together? I am in process of demolition and then will begin the whole basement renovation (contractor actually) of which the HT will be a part, but I would like to figure out ahead of time the arc on my diy screen so I can be building it while the rest of the basement is under construction.
 
#29 ·
I don't think you would know for sure the curvature needed from just numbers (screen size distance etc ). Too many variables.
 
#31 ·
I don't know of any other way to determine how much curvature is needed to correct for the pincushion effect other than to have the projector and anamorphic lens in place, then you do your correction on your actual set-up. The screen material that I used is a Vutec Brite White with a 1.3 gain and yes it does have enough body strengh and stiffness to maintain a smooth curvature when installed with the 1" Velcro border to the inside border of the frame.
 
#32 ·
Looks great, congratulations on your hard work, and the payoff. I have a similar plan in mind, finally got my cave plans approved by the city, need to do framing etc., many months away from seeing an image - sniff - oh well, have a couple flat panels in the house to "tide me over" until then.
 
#33 ·

Quote:
Originally Posted by tr6 /forum/post/12257483


The screen material that I used is a Vutec Brite White with a 1.3 gain and yes it does have enough body strengh and stiffness to maintain a smooth curvature when installed with the 1" Velcro border to the inside border of the frame.


Is there a noticeable difference among the various screen materials? I bought some Pfifer 4500 for a 10' wide DIY curved screen. Has anyone used this to make a screen? How would you suggest attaching the fabric to a curved screen made similar to TR6's screen? The velcro seems like a good choice, but I am wondering if there are any other ways. I would hate to use up the fabric only to find that there are sags in the screen.
 
#34 ·
I have phifer 4500 and might use the velcro, if your just sticking it on you have to get the kind with the acrylic industrial strength glue I believe. tr6 (different material) and one other person who also had 4500 had the velcro sewn on. My other option is to use window screen supplies. In Home Depot and lowes they have tracks you can attach to metal or wood, you'll have two channels with which to feed the spline to secure the material. Still a ways off tough.
 
#39 ·

Quote:
Originally Posted by tr6 /forum/post/12257483


I don't know of any other way to determine how much curvature is needed to correct for the pincushion effect... The screen material that I used is a Vutec Brite White with a 1.3 gain and yes it does have enough body strengh and stiffness to maintain a smooth curvature

Thanks for that.


I understand the technique for identifying & correcting for "edge focus" and apparently the closer the screen the less-well a pj's optics correct for a screen being flat, but...


Since PJs are designed & sold for flat screens, is it reasonable for me to assume that if my pj-to-screen distance is sorta in the middle of the recommended range for a pj, that "pincushion effect" is negligible? If anyone here knows/has heard of any "rules of thumb" in this regard by all means speak up. WAGs are welcome too!
 
#40 ·
I am fairly sure the pincushion being discussed here is the extra effect from using the prisms for horizontal expansion. This is above and beyond the pincushion already corrected for by the projector's lens.
 
#41 ·

Quote:
Originally Posted by Riblet /forum/post/12319575


I am fairly sure the pincushion being discussed here is the extra effect from using the prisms for horizontal expansion. This is above and beyond the pincushion already corrected for by the projector's lens.

Oops, well duh! Does everybody concur? I figgered pincushion was anywhere, wasn't thinking in terms of the panamorph add-on.
 
#42 ·
If the lens does add some picushion affect and we curve our screen to account for it,then what happens when we passthru or remove the lens?
 
#44 ·
Since the greatest distance-from-flat will be at the 2.35:1 setting, there will be less focal distance change for the 1.85:1 setting. In other words, the negative effect without the prisms on 1.85:1 material is less than the positives of 2.35:1 with prisms.
 
#45 ·
I authored a spreadsheet for calculating pincushion distortion, screen curvature, throw ratio and lots of other useful stuff based on screen height and throw distance only (that's actually all you need to know, plus an understanding of optics - which is my job).


If anyone wants to try it out, PM me. PLEASE INCLUDE YOUR EMAIL ADDRESS IN THE PM.


CAVX's broomstick is a good practical method, but the spreadsheet approach allows you to simulate your installation before deciding on a room size, projector model or where you're gonna buy the broomstick. Plug in your room ideas and play.
 
#46 ·

Quote:
Originally Posted by Aussie Bob /forum/post/12439616


I authored a spreadsheet for calculating pincushion distortion, screen curvature, throw ratio and lots of other useful stuff based on screen height and throw distance only (that's actually all you need to know, plus an understanding of optics - which is my job).


If anyone wants to try it out, PM me.


CAVX's broomstick is a good practical method, but the spreadsheet approach allows you to simulate your installation before deciding on a room size, projector model or where you're gonna buy the broomstick. Plug in your room ideas and play.

Bob, you got pm!

TIA!

____

Axel
 
#47 ·

Quote:
Originally Posted by Aussie Bob /forum/post/12439616


I authored a spreadsheet for calculating pincushion distortion, screen curvature, throw ratio and lots of other useful stuff based on screen height and throw distance only (that's actually all you need to know, plus an understanding of optics - which is my job).


If anyone wants to try it out, PM me.


CAVX's broomstick is a good practical method, but the spreadsheet approach allows you to simulate your installation before deciding on a room size, projector model or where you're gonna buy the broomstick. Plug in your room ideas and play.

Now where talk'n. Thanks for the post, PM sent

Gary
 
#49 ·

Quote:
Originally Posted by Aussie Bob /forum/post/12439616


I authored a spreadsheet for calculating pincushion distortion, screen curvature, throw ratio and lots of other useful stuff based on screen height and throw distance only (that's actually all you need to know, plus an understanding of optics - which is my job).


CAVX's broomstick is a good practical method, but the spreadsheet approach allows you to simulate your installation before deciding on a room size, projector model or where you're gonna buy the broomstick. Plug in your room ideas and play.

Really? That's cool. I thought you'd need to know the specific characteristics of the HE lens being used. Can't a higher quality lens produce less pincushioning than a lower quality one?
 
#50 ·
Hello Everyone,

room where I am going to put a I am newx to the site and need some assistance.

I have a 132" Curved Screen. I am looking for the way to figure out the arch. I read on one site that I should be 6" from center point, but am looking for a formula or a way to confirm that. Any help would be appreciated.
 
#51 ·
Send a PM to Aussie Bob in post number 45 for a spreadsheet to figure out your curve.
 
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