Welcome to this wonderful communication tool, the FORUM. There is more experience and knowledge here than anyone could ever afford to purchase.

With regard to the lens calculation program, I have used it with excellent results. The accuracy of the dimensions entered reflect directly in the resulting answers. I think the computer folks call this GIGO!!

The one problem I have encountered with all but the very first downloaded program is: The elevation of the PROJECTOR does not move in my computer. I have reloaded the program and it still doesn't work. This makes the keystone calculations inoperative.

My version does not have the latest variable prime lenses indicated.

Thanks for providing your wonderful tool at no cost to us.

Sincerely, KEN

I can't imagine why the projector elevation doesn't work. I've never seen that one before.

You really need to get the latest version.

It's on the web site.

If you'd do that and let me know if it works now I'd appreciate it.

Thanks for the new version, the projector now moves and keystone corrections are working.

You're welcome of course. As I told you offline (and I'll repeat for those listening) There actually *is* a setting that will keep the projector locked so that the projection axis is perpendicular to the center of the screen. This setting really just dumbs down the program so that it doesn't do keystone calculations.

Someone wanted that a while back and we added it . . .

The other function of your program which limits my use is the tilt of the screen. Since many of my customers are "historic" buildings, the booths are located some distance above the screen. In all of these situations it is necessary to tilt the top of the screen away from the audience, backwards, in order to reduce keystoning.

The program provides for tilting the screen but only with the top toward the audience (projector below the screen center).

Could the program be made to allow the screen to tilt in both directions?

In fact, at the moment the program only allows you to tilt the screen backward.

When it's at 0 (usually the default) it does say "0 degrees tilted forward" which is sort of a bug. It should just say 0 degrees tilt.

I don't know who would want to tilt it forward, but we could do that.

I'm glad you found it to be accurate. That was of course one of our motivations for writing the program. The more accurate the calculations are the less we have to exchange lenses due to incorrect sizes.

We really *did* work hard on that, getting the calculations right. I don't even want to recall how painful and time consuming getting the keystone distortion and curved screen distortion calculations running correctly.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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I don't know who would want to tilt it forward, but we could do that.

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Dwight, there are still many drive-ins out there, and new ones being built regularly. Please do! Thanks.

The other use I have for the 'forward tilt' is when we use a digital image from within the seating for business meetings. The program you have is very useful in determining the location of the 'projector' in advance of the arrival of the meeting.

Thanks, KEN

Every one of these enhancements costs me more than you can imagine, so someone owes me a beer for this one . . .

:> )

Video projection setups which are always starving for light (except of course DLP which is just starving for resolution and contrast), often use forward tilt and high gain screens to eek out every bit of light they can. The Advent VideoBeam used a precise forward tilt and dual-plane curve to redirect precious light back to the audience to great light gain advantage.

You're right of course, tilting the screen can deliver light to the audience. You sort of get that with Stadium Seating when you tilt backward, redirecting the light to viewers who are up a bit higher . . .

Unless the programmer tells me it's impossible, and I don't expect him to, we'll add the ability to tilt both directions into v3.1.