Film-Tech Forum ARCHIVE: Digital Drive-In Projection

This is topic Digital Drive-In Projection in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Barry Floyd (Member # 385) on 11-22-2005, 09:55 AM:

I was contacted by a guy who wants to propose to his girlfriend this Wednesday night at our theatre. They had their first date there, and he wanted to propose there as well.

During our phone conversation, he stated he wanted to bring a small video projector and show about 10-15 minutes of footage he has taped of well-wishes from friends, family, etc. I told him I was VERY doubtful if it would work because of the lamp size in the projector, the wrong lens sizes, the throw distance, etc., but he said he wanted to try.

I met him out at the theatre last night after work, and he pulled out this little conference room table video projector, about the size of a small VCR. I was thinking to myself ... NO Way was this going to work as we were standing 275 feet away from the screen. He plugged it in and I must honestly say... I was AMAZED. It actually worked. Albeit, the mismatched lens made the picture about twice the size of the screen, and the picture was a little dark... but with about twice as much light and the right lens... it definetely has potential for something. (Advertising slides, private rentals, etc.)

He played part of his tape, and I walked up to the bottom of the screen expecting to see pixels the size of basketballs.... it was perfect.

This wasn't some fancy digital cinema thing, this was an ordinary business-style conference room table video projector.

I believe the name brand was "In-Focus", and the model number was the "Screenplay 5000"

Thought you guys might like to know.

Posted by Richard May (Member # 2627) on 11-22-2005, 10:48 AM:

Someone did the same exact thing here. He brought in a DVD of a proposal and ran it through our projector (EIKI LCX986). Small boardroom projector. We run feature films on it from a Digibeta deck. Unfortunately, it looks pretty good.

Posted by John Pytlak (Member # 331) on 11-22-2005, 10:57 AM:

The name of the game is "Lumens". Most drive-ins fall far short of the 16 footlamberts specified by standard SMPTE 196M. In fact, SMPTE Recommended Practice RP12-1997 "Screen Luminance for Drive-In Theatres" specifies:

quote:
4 Luminance level

4.1 In an ideal situation, when permitted by the
technology of motion-picture projection, and when
the viewing environment is sufficiently close to
that of the indoor theater, the screen luminance
and distribution shall be that specified in
ANSI/SMPTE 196M, 16 fL ± 2 fL (55 cd/m2 ± 7
cd/m2), as measured from a position on the
longitudinal centerline of the ramp area and midway
between the foremost and rearmost ramps.
4.2 The recommended minimum luminance at
the center of the screen shall be 7 fL (24 cd/m2),
as measured from the central position defined in
4.1.
4.3 When maximum compromise must be made,
as discussed in annexes A.1 and A.2, the luminance
at the center of the screen, measured
from any car position, shall in no case be less
than 4.5 fL (15 cd/m2).

So, even 4.5 footlamberts is not unusual (but not ideal) in drive-in theatres. Assuming a freshly painted matte white screen with a gain of 0.9, a 30 x 40 foot video image would require (30 x 40 x 4.5) / 0.9 = 6000 lumens to get 4.5 footlamberts.

Since the InFocus ScreenPlay 5000 has a rated output of only 1100 lumens, you likely were well below 1 footlambert on your screen. You're drive-in must have very little ambient light shining on the screen!

Posted by Barry Floyd (Member # 385) on 11-25-2005, 01:18 AM:

For what it's worth.. I stood outside last night and watched the video that was projected onto the screen. By moving the projector up closer to the screen, the image filled the screen top to bottom, and it also made the image brighter. He set the projector on a small card table and aimed it up to the screen. The projector had an auto-keystone correction function built-in and it worked beautifully. The colors were rich and clear, and the image was sharp as a tack.

I was "sold" on the technical side of it. Like I said earlier, a little more light and with the right lenses, dragging and dropping icons on a server screen would sure beat the heck out of spending countless hours on Thursday nights building and breaking prints.

Oh, by the way...... she said YES!