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Author Topic: Projector Setup  (Read 3558 times)

Tamar Ghobria

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Projector Setup
« on: January 01, 2014, 09:24:12 pm »

Is there a general right way to line up a projector to a projection screen...In other words is it best to line up the image to the bottom of the screen first? I generally use my laptop and use my desktop screen as my guide...The process seems to take us quite a while and I feel like if I had a system that it may improve setup time...
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Ryan C. Davis

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Re: Projector Setup
« Reply #1 on: January 01, 2014, 10:57:17 pm »

I guess that kind of depends on if you are doing something quick and dirty on a tabletop or if you're setting up a nice projector in a semi permanent (mounted) environment.

I always start by getting the top lined up to the screen, good starting point. Then I aim the projector left or right to get the geometry right- this while looking at how tall the left is and how tall the right is. If the left is taller it means that your projector is aimed left and the distance from the lens to the screen is farther than the right. Short answer to this, if the left is taller, pan right until they're the same size.  next do the same thing with the tilt but this time you're looking to see if the top is narrower than the bottom and vice versa. Ideally you have projector with horizontal and vertical lens shift. If that's the case, zoom the image so its smaller than the screen and get it perfectly square, then use lens shift to move the image to the right spot on the screen and while you do that keep massaging the zoom until you get the right size image in the right place. But remember, once you get the initial tilt and pan perfect so the geometry looks good you shouldn't need to touch it from there unless you move the projector or screen.
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Jonathan Kok

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Re: Projector Setup
« Reply #2 on: January 02, 2014, 01:50:34 pm »

Is there a general right way to line up a projector to a projection screen...In other words is it best to line up the image to the bottom of the screen first? I generally use my laptop and use my desktop screen as my guide...The process seems to take us quite a while and I feel like if I had a system that it may improve setup time...
This is your friend:

Unless your laptop is going to be the only source shown on the projector, then using your laptop might not result in the perfect image, as the projector may not fill the screen with it. Better to use the built-in test grid, if it has one, or just the 'no image' screen, if it doesn't (you may have to change a setting to get a color on the 'no image' screen).
First and foremost, put the projector in the right place to begin with. This means math. Remember, the LENS has to be centre to the screen; NOT the projector. For common projectors, this means the projector is placed 2-3" off-centre. Good projectors will have a good manual detailing the vertical position of the projector, usually as a ratio to the screen size. If you screw this up, and the projector doesn't have lens shift, then you're gonna have a fight. If you DO get this correct, then it's just a matter of leveling the projector with, well...a level. Some minor tweaks, and done. If you have to keystone, you've failed at positioning the projector.
For general purposes:
If the top/bottom aren't parallel with the screen, then your YAW (left/right turn) is not correct.
If the top/bottom ARE parallel, but the left/right are NOT, but are mirror images in slope, then your PITCH is not correct (front/back tilt).
If the top/bottom ARE parallel, but the left/right are NOT, AND are NOT mirror images of each other, then your ROLL is not correct (left/right tilt). Which is a fun one, as you'll have to adjust both roll and yaw to fix it.
I'll usually focus on getting the YAW and ROLL correct first.
As far as ZOOM goes, the image will get larger from the closest point to the screen. This typically means that, when you zoom out, the bottom of the image will barely move down, while the top of the image will move up a whole lot more as you zoom out. Assuming we're not talking about inverted projectors.

As far as installs, the better mounts will have cams and brakes using plastic washers that will make minor adjustments to the projector a lot easier than the cheap ones.
« Last Edit: January 02, 2014, 01:55:56 pm by Jonathan Kok »
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Tamar Ghobria

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Re: Projector Setup
« Reply #3 on: January 02, 2014, 02:11:48 pm »

This is your friend:

Unless your laptop is going to be the only source shown on the projector, then using your laptop might not result in the perfect image, as the projector may not fill the screen with it. Better to use the built-in test grid, if it has one, or just the 'no image' screen, if it doesn't (you may have to change a setting to get a color on the 'no image' screen).
First and foremost, put the projector in the right place to begin with. This means math. Remember, the LENS has to be centre to the screen; NOT the projector. For common projectors, this means the projector is placed 2-3" off-centre. Good projectors will have a good manual detailing the vertical position of the projector, usually as a ratio to the screen size. If you screw this up, and the projector doesn't have lens shift, then you're gonna have a fight. If you DO get this correct, then it's just a matter of leveling the projector with, well...a level. Some minor tweaks, and done. If you have to keystone, you've failed at positioning the projector.
For general purposes:
If the top/bottom aren't parallel with the screen, then your YAW (left/right turn) is not correct.
If the top/bottom ARE parallel, but the left/right are NOT, but are mirror images in slope, then your PITCH is not correct (front/back tilt).
If the top/bottom ARE parallel, but the left/right are NOT, AND are NOT mirror images of each other, then your ROLL is not correct (left/right tilt). Which is a fun one, as you'll have to adjust both roll and yaw to fix it.
I'll usually focus on getting the YAW and ROLL correct first.
As far as ZOOM goes, the image will get larger from the closest point to the screen. This typically means that, when you zoom out, the bottom of the image will barely move down, while the top of the image will move up a whole lot more as you zoom out. Assuming we're not talking about inverted projectors.

As far as installs, the better mounts will have cams and brakes using plastic washers that will make minor adjustments to the projector a lot easier than the cheap ones.


I am running a macbook through a Roland v-40hd which has the zoom and position joysticks directly on the mixer...I never thought of using the grid feature to set the screen...I am also using a projector stand (rear short throw projection) which tilts up...There are ton of variables here...thanks for the feedback
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Mac Kerr

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Re: Projector Setup
« Reply #4 on: January 02, 2014, 02:22:53 pm »


I am running a macbook through a Roland v-40hd which has the zoom and position joysticks directly on the mixer...I never thought of using the grid feature to set the screen...I am also using a projector stand (rear short throw projection) which tilts up...There are ton of variables here...thanks for the feedback

The point of the level is to not tilt the projector. It should be level and positioned within the lens shift limits of the projector, If it is level and you use lens shift you will not need ketstone correction.

Mac
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Jonathan Kok

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Re: Projector Setup
« Reply #5 on: January 02, 2014, 04:28:40 pm »


I am running a macbook through a Roland v-40hd which has the zoom and position joysticks directly on the mixer...I never thought of using the grid feature to set the screen...I am also using a projector stand (rear short throw projection) which tilts up...There are ton of variables here...thanks for the feedback
As Mac says, the projector stand, and projector, should sit LEVEL.
Depending on the projector, it may have to go quite high, as short-throws really limit the lens-shifting capabilities, and you'll lose the corners of the screen as you get to the lens-shift limits. This is more of an issue on swappable-lens projectors; if your projector is built to *only* be a short throw, then it's not as much of an issue. But it still needs to sit level, and vertically in the correct place.
When working with rear short throw, I''ll usually get it close with the projector, then move the screen the last couple of inches. Typically, I'll get the top left, bottom left and bottom right aligned, then move the right side of the screen in/out until the top-right is correct. Trying to get the projector exactly correct is, absolutely, a PITA on short-throws.
I'm not quite sure what you mean about the zoom/position on the V-40HD; these have nothing to do with focusing the projector.

Of course, if you're using the same screen/projector combo frequently, you could probably come up with some sort of clothespin/string 'jig' to make it go a whole lot faster.
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Luther Bell

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Re: Projector Setup
« Reply #6 on: February 21, 2014, 10:38:39 pm »

If you have to keystone, you've failed at positioning the projector.

I am by no means saying that I am a lazy projectionist but I have found that the need for keystone is a correlate of the amount of money that is renting that projector.

Unless you are flying the projector, and that doesn't always work, you typically won't come close to "proper" with front projection.  With rear projection, you pretty much don't have an excuse not to get the lens centered.  Just make sure that you are getting the projector to the proper height in the safest way.  Don't have a pic of your projector end up on an Internet forum because it is sitting on top of a 6' step ladder.
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Mac Kerr

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Re: Projector Setup
« Reply #7 on: February 21, 2014, 10:57:52 pm »

Unless you are flying the projector, and that doesn't always work, you typically won't come close to "proper" with front projection.  With rear projection, you pretty much don't have an excuse not to get the lens centered.

The projector does not have to be centered on the screen vertically, it just needs to be perpendicular. You then use lens shift to move the image till it's centered on the screen. There should not be any keystone unless the lens is not perpendicular to the screen. Some projectors can be as much as a quarter screen height below the bottom of the screen and still shift the image to be centered on the screen without keystone.

Mac
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Jonathan Kok

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Re: Projector Setup
« Reply #8 on: February 22, 2014, 04:05:19 pm »

I am by no means saying that I am a lazy projectionist but I have found that the need for keystone is a correlate of the amount of money that is renting that projector.

Unless you are flying the projector, and that doesn't always work, you typically won't come close to "proper" with front projection.  With rear projection, you pretty much don't have an excuse not to get the lens centered.  Just make sure that you are getting the projector to the proper height in the safest way.  Don't have a pic of your projector end up on an Internet forum because it is sitting on top of a 6' step ladder.
I had installs on my mind when I posted that, more than production purposes. That being said, there's really only one exception for needing to keystone: Odd projector placement requirements, usually related to ground-support front projection using short throw lenses on a swap-able lens projector. But unless there's a specific reason a projector cannot go where it needs to be, you really shouldn't need to keystone. It'll mean investing in proper projector stands, like the Da-Lite Project-O-Stands, to get the height right. But it's not like those are expensive.
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Mac Kerr

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Re: Projector Setup
« Reply #9 on: February 22, 2014, 04:16:26 pm »


I am running a macbook through a Roland v-40hd which has the zoom and position joysticks directly on the mixer...I never thought of using the grid feature to set the screen...I am also using a projector stand (rear short throw projection) which tilts up...There are ton of variables here...thanks for the feedback

What projector and lens are you using? How big is the screen? How far from the floor is the bottom of the screen? What is the throw from the projector to the screen?

The projector manual should tell you how much vertical image shift you can get with lens shift. With consumer projectors it is usually at least half a screen height, so if the projector is at least as high as the bottom of the screen you can use lens shift to center the image on the screen. If you use lens shift you will not get any keystone, the image will just move up without changing geometry.

Mac
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