View Full Version : How much zoom to do this?
Bruce Wayne
07-26-07, 03:31 PM
I have an IN72 prejecting onto a 92" diag screen from around 15'. I only want the benefit of a crisper image and a little brighter picture so I would like to keep the screen size the same. I hope I can move the lens out of the way to watch 16:9 material, then zomm in, and slide the lens in place to watch 2:35 material.
My big concern is this, when I zoom in all the way, I have around 8-10" on each side of the screen. Will this be enough when I slide the lens in place? Or will it overshoot the side of the screen?
On another note, if CA is apparent close to the edges, how far from the edge does it begin to be apparent?
cynical2
07-26-07, 04:16 PM
I have an IN72 prejecting onto a 92" diag screen from around 15'. I only want the benefit of a crisper image and a little brighter picture so I would like to keep the screen size the same. I hope I can move the lens out of the way to watch 16:9 material, then zomm in, and slide the lens in place to watch 2:35 material.
My big concern is this, when I zoom in all the way, I have around 8-10" on each side of the screen. Will this be enough when I slide the lens in place? Or will it overshoot the side of the screen?
On another note, if CA is apparent close to the edges, how far from the edge does it begin to be apparent?
I'm confused...your current 92" screen is 16:9 or 2.37:1? I'm confused with exactly how you want to do it...are you currently filling the 92" screen with 16:9 material?
The ratio between 16:9 and 2.37:1 is 1.33x. So the image will display 1.33x wider with the lens in place than with it moved out of the way. I'll leave my input at that for now...until I understand a bit more exactly what you want to do.
Bruce Wayne
07-26-07, 05:34 PM
are you currently filling the 92" screen with 16:9 material?
Yes, the current setup is a standard 92" 16:9 screen. I need to do a constant width setup but I do not know how to acheive this with a DIY approach. Is it as simple as turning the lens sideways?
When you use a HE lens, there is NO ZOOM required when moving the lens in or out of the light path. The name Constant Image Height is in place because the image height remains the same. The only difference is the width that changes from 1.78:1 to 2.37:1.
For more info, click on the CIH Explained link in my signature...
Mark
are you currently filling the 92" screen with 16:9 material?
Yes, the current setup is a standard 92" 16:9 screen. I need to do a constant width setup but I do not know how to acheive this with a DIY approach. Is it as simple as turning the lens sideways?
So if you are not looking to expand the width of your picture you want a VC lens assuming that the Throw ratio is enough to work with one. I am not that UP on the required throw ratio with VC lenses. With that lens you would not zoom any more than what you have currently to fit your screen. You would need something that would vertically stretch your image, either a projector that does or a DVD player that does, but that would only help you with movies and there are no HD type that do currently. or buy a separate scaler. then your VC lens would compress the picture back down to size again but using all the pixels in your panel. the picture would not be any wider with this lense.
then your VC lens would compress the picture back down to size again but using all the pixels in your panel. the picture would not be any wider with this lense.
Correct, but it can actually be brighter as you are now compressing the light into a smaller area...
Mark
Bruce Wayne
07-30-07, 02:06 PM
Can VC be done DIY? This is exactly what I want to do.
Yes it can. Why do want VC?
Mark
Yes it can. Why do want VC?
Mark
The OP says in the first post that he wants to keep the same screen size he has and a crisper image and to increase the brightness.
Bruce, keep in mind that the crispness of the image can be the projector you are using or the screen as well.
Bruce Wayne
07-31-07, 12:51 PM
Yes it can. Why do want VC?
Mark
I have a 92" diag. screen and I want to keep the 2:35 picture inside this size. I want to move the lens to watch 16:9 material at the full 92" I want to use the stretch mode of my IN72 on 2:35 material to create a full 16:9 image using all the pixels, then compress it back to the 2:35 size. This way I gain resolution and added brightness without having a screen that eats my living room.
If I stretch the image vertically and then stretch it horizontally I will far exceed my current screen size. Does this make sense to you?
Bruce Wayne
07-31-07, 03:03 PM
Does this make sense to you?
This kinda sounded smart allecy after I read it, I in no way meant it to be that way. I just meant do I make any sense at all by explaining what I want to do?
Your response made perfect sense, so a VC sounds the way to go...
You should contact Panamorph and see if their VC is still on special. It was $495.00 for a time...
Mark
Bruce Wayne
08-01-07, 02:09 PM
Your response made perfect sense, so a VC sounds the way to go...
You should contact Panamorph and see if their VC is still on special. It was $495.00 for a time...
Mark
If I had $500.00 I would not be in the DIY forum and I would sell my IN72 and upgrade to a HI-DEF unit that would give me more pixels in the 2:35 area than my 480P unit would with a lens.
I want to do a DIY VC lens for a buck or two. If the prisms you guys use are arranged differently and flipped sideways, will this compress the image?
ComputerCowboy
08-02-07, 09:27 AM
I want to do a DIY VC lens for a buck or two. If the prisms you guys use are arranged differently and flipped sideways, will this compress the image?
Yes that will work. I got the largest size prisms I could from www.glassgraphics.com
They won't sell to you unless you are a distributor, or have a taxid # I guess. My landlord is in the promotional materials biz so I had him order them for me. They cost $72 shipped and they work very well. With some tweaking I have been able to eliminate almost all refletions.
http://glassgraphics.com/2007Catalogue/lg/89453_catalog.p15.jpg
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