help with online distance calculators

[myke]

Please help me understand this distance calculator. I just bought the Viewsonic 8200 which as of right now comes with a free 80inch screen and mount. (you can also upgrade to a 100”)

I’m not understanding some of the numbers on the projector central app. When the app loads up for my projector it shows a recommended distance of 16.7. Then on the image diagonal numbers it shows the following numbers: 66” vertical, 135” diagonal and 118” horizontal. Does that mean it is recommending I get a 135” inch screen for widescreen 16:9 viewing? I thought screen size was always measured horizontally??

Then on the mounting numbers I get 22.7 which I assume means I need to make the decision of placing it on the floor or from the ceiling at that height?

If I’m reading this calculator at all correctly the image would need to be much larger than the 80-100 inch screen and to get the most out of it I need a bigger screen. I want to make sure im doing this right and not just trying to take advantage of the freebie screen and getting crappy performance.

Here is the link. There is also another one on the viewsonic website.

ViewSonic Pro8200 Projection Calculator - Throw Distance and Screen Size

Thanks in advance

 

[agarwalro]

Does that mean it is recommending I get a 135” inch screen for widescreen 16:9 viewing?

The size of the screen depends on how far you mount the projector and min to max zoom it is capable of.

I thought screen size was always measured horizontally??

TV, computer monitor, projector and all screen sizes are specified by their diagonal measurement and ratio of (horizontal) length to (vertical) height.

Then on the mounting numbers I get 22.7 which I assume means I need to make the decision of placing it on the floor or from the ceiling at that height?

This is maximum distance between screen edge and projector lens level to ensure proper aspect ratio is achieved.

I would recommend just calling up Projector People customer support. They will ensure you get the screen that fits your intended use.

 

[BMXTRIX]

You were answered pretty well on the PC forums, but to add...

You are looking at default numbers for that projector.

Your screen size should be determined by seating distance (as described in their forum screen FAQs).

So, if you are sitting 12' from the screen, you should use about a 110" diagonal screen.

The 22.7" is the distance between the center of the lens and the bottom of the image (if floor mounted). You may use keystone correction to allow you to get the image a bit lower if needed... Or, if ceiling mounted, a bit higher.

 

[myke]

You were answered pretty well on the PC forums, but to add...

You are looking at default numbers for that projector.

Your screen size should be determined by seating distance (as described in their forum screen FAQs).

So, if you are sitting 12' from the screen, you should use about a 110" diagonal screen.

The 22.7" is the distance between the center of the lens and the bottom of the image (if floor mounted). You may use keystone correction to allow you to get the image a bit lower if needed... Or, if ceiling mounted, a bit higher.

Thank you again for the reply. So the distance calculator is based more on the seating distance? I was concerned with adjusting the image to near or too far and getting a crappy image. Ill go back and read the FAQ's.

Last question. What is the PC forum? Can you point me to this posting. I dont post anywhere but here and one other forum. I would like to read it since you mention it had some good answers.

 

[myke]

This helped on the FAQ:

In our example the projector is intended for Video/Movies so the setup has been optimized by the Calculator Pro to generate a brightness of 16 fL (foot-Lamberts), which is the optimal value that your local movie theater attempts to achieve. If you cannot get your room as dark as a movie theater, then you might consider a smaller screen, a higher gain screen, or a brighter projector for the screen size you've chosen.

For a business application where ambient room light is needed for note taking, 32 fL is usually a good setting. In a well lite room it may be necessary to go as high as 50 fL.

Assuming you can manage ambient light, the Green Zone will be the ideal area for your setup. If the room is well lit, a setting in the Red Zone may be necessary. Avoid going into the Yellow Zone unless you have complete control over ambient light.

The Image Diagonal and Throw Range can be controlled by the vertical slider.

 

[jostenmeat]

PC is Projector Central forum. I haven't been over in a while, but BMX has been the moderator there for as long as I knew of its existence.

Is the "other forum" you mention AVS? That's where you will see some people insist on using screen width and not diagonal. The one way I do think it makes discussion easier when using width with PJ setups is because of the number of people there that use scope setups. When using such a setup, you're pretty much maxing our for 2.35:1, and whatever 1.78 is left is what you get. So I could give my opinions about viewing distance/angle more easily because by using width I have an idea. (It's easier than calculating changing dims back and forth for the different ARs.) That said, I pretty much talk in terms of diagonal only, and it doesn't slow me down to much from helping people in the end.

The PJ calc is a rough guide. Sometimes it will be more inaccurate than other times. You don't think they're taking every new PJ ever made out of the box and calculating this every time, for every generation, do you? I imagine they are using the mftr given specs and such.

Then you have to account for unit to unit variation, both with PJ and lamps, lamp life, ambient lighting.

So anyway, the closer your PJ the brighter it will be, the farther the more contrast. However, the big deals with brightness are room conditions and screen size.

IMO, you want bigger than 110" from 12'. So what to do? Just play around and fire her up on a blank wall for a few days, using all the different types of source material that you will use, and all questions will be answered.