Front Projection...help:(

[Jason Eitelbach]

Hello all,

 

So I'm trying to set up a front/rear projection shot. It's going to be a tight interior of a car with moving background generated by a 16mm Xenon projector.

 

I can't seems to find a projector with a hard wired shutter controller to sync to and I can't modify the one that I have access to (not mine).

 

I've shot TV screens before with a Tobin Miliframe controller adjusting the frame and using the phase button to remove the rolling bars. Could I use a similar device to remove or minimize flicker or should I just 86 the shot?

 

The projector I have can also run at 18fps would it be helpful to run the projector at that speed?

 

I've called most folks I think of (Panavision local AV geeks etc.) and have found zero answers. Everybody uses video or green screen now it seems, but the director wants the look of film projection.

 

thanks,

je

[Stuart McCammon]

First off, I am not real clear on how front projection would work in a car - as far as rear projection, it has always been a pain to set up - a quick search of LA411 reveals no rear projection companies, so at this point you probably need to call around to studios and see if you can find someone old enough to remember how to do it right, and then it will cost beaucoup bucks - I would greenscreen it my friend)

 

All the best,

 

Stuart McCammon

[Jason Eitelbach]

Well the film's being finished optically, so I'm not sure how green screen mattes work in a contact print world.

[Stuart McCammon]

Mattes were a film technology long before the advent of FCP - there are two standard matte colors, matte blue and matte green - most people use matte green because matte blue had a disturbing tendency to cause people's eyes to get matted out.

 

Here is a site with tons of information about film post-production, I don't know anything about the company but it provides all of the detail you would ever want in terms of understanding the film finishing workflow:

 

http://www.wrslabs.com/printing.html

 

As a side note, one of the biggest problems with rear projection is matching the brightness of the image to lit actors. You light your actors, and some of it spills onto the rear projection screen, thus washing out your projected image. Back in the day, one rear projection system used three projectors, synchronized to the camera, to get enough image on the screen.

 

All of which sounds like it is a bit beyond most student films - hence the suggestion that you simplify your life (somewhat, mattes can be a bear to light correctly).

 

Best of luck!

 

Stu

[Leo Anthony Vale]

Hello all,

 

So I'm trying to set up a front/rear projection shot. It's going to be a tight interior of a car with moving background generated by a 16mm Xenon projector.

 

 

 

I've shot TV screens before with a Tobin Miliframe controller adjusting the frame and using the phase button to remove the rolling bars. Could I use a similar device to remove or minimize flicker or should I just 86 the shot?

 

The projector I have can also run at 18fps would it be helpful to run the projector at that speed?

 

You won't get a bright enough image in a size big enough to go behind a car.

Maybe with front projection, making a screen will be tricky. Look at how blotchy the front projection screen

is in 'Barbarella'.

Don't know the price, but for one shot more bother and expence than it's worth.

 

A different frame rate on the projector than on the camera won't give a clean image.

[Christian Appelt]

What kind of 16mm projector are you using? Try to get one with a three-blade shutter, run it at the frequency you are shooting and let it run for a few minutes before you start shooting (speed may vary when you start with a cold projector mechanism):

 

The 3-bladed shutter should minimise the flicker problem, with moving backgrounds it is likely to be acceptable.

You may also use a speed checker to check the actual frame rate of the background projector and alter your camera fps to match it.

 

Shoot a short test with these little precautions.

[Jason Eitelbach]

Got my tests back they look great.

 

Scotchlite makes a great screen, on axis the gain boost is amazing. It also has a nice "texture" to the image and very even illumination, much better than rear projection.

 

Got no flicker on an Arri 35-III without a sync box at 24fps, some at 20fps, none at 6fps and some a 8fps. Did use a speed controller for the camera and kept my Eiki Xenon projector constant at 24 fps.

 

I shot the tests without a beam splitter and just postioned the projection as close to the lens axis as possible, about 10" above the lens to throw any shadows down. I might get a piece of semi-silvered glass to test, but I may just get as close as we can. I know that doing that doesn't take full advantage of the reflective power of the Scotchlite but it seems like enough.

 

Metering the screen is difficult since angle of view is so critical to how bright it is. I measure a 2.0/2.8 falling on the screen (the projector was 20' away) and a 8 refecting off the screen from just above the camera viewfinder so I lit the foreground to a 5.6. Couldn't use an incident meter because it casts a shadow on the screen.

 

From looking at the tests it appears as though getting the background 1 to 2 stops brighter is going to be no problem.

 

If anyone wants more info on my setup, let me know. You can e-mail me at jephotographs....at....gmail dot com. I'll be posting the final shot in three weeks or so.

 

thanks,

je

 

p.s. Doing the shot this way is going to save us hundreds of dollars in post-production opticals, interpositives etc., look more unique and cost me almost nothing to set up, so no more "do it green screen advice" :D