Filming a projection

Marty Hamrick · May 1, 2004

Hi Folks,

Got a shot at a commercial here that involves a football coach reaming out his players while showing game footage on an old 16mm projector.We need to see one master shot with the coach near the screen and projection with the projector in the FG.

This is low budget.I may end up shooting it on video and using a telecine projector,but if we go with film,our camera choices are an Arri S or Auricon Pro 600.I've been thinking of doing the sync by way of the AC mains,but such gear is hard to come these days.Anybody here got any McGiver tricks?It's also been over 20 years since I did anything like this for film so I'm not sure how to meter this.

Marty

David Mullen ASC · May 1, 2004

Since the 16mm projector either has a double or a triple-bladed shutter, you can shoot the image without any sycning if you don't mind the pulsing and flickering. The more blades in the shutter, the less flickering.

Otherwise, you need to use a projector with a single-bladed shutter (like are used with rear projection set-ups) and sync the camera's shutter to it (I've never done it myself.)

Marty Hamrick · May 2, 2004

Since the 16mm projector either has a double or a triple-bladed shutter, you can shoot the image without any sycning if you don't mind the pulsing and flickering. The more blades in the shutter, the less flickering.

Otherwise, you need to use a projector with a single-bladed shutter (like are used with rear projection set-ups) and sync the camera's shutter to it (I've never done it myself.)

Since the 16mm projector either has a double or a triple-bladed shutter, you can shoot the image without any sycning if you don't mind the pulsing and flickering. The more blades in the shutter, the less flickering

Probably the way I go.The shot's about 8 seconds long and some flicker may not be objectionable.At this point it may end up being shot on video with an LCD projector anyway.

Otherwise, you need to use a projector with a single-bladed shutter (like are used with rear projection set-ups) and sync the camera's shutter to it (I've never done it myself.)>

Right,I've done this years ago with a super 8 projector synced up with a 1 F switch synced to a super 8 camera.I just wondered if there was a way to with 16mm.I know how to install the switch in the projector,but not sure how to sync the Arri S this way.

I was also wondering about how to meter the projection screen with the FG since the image on the screen is only up for 24th of a second.

Marty

David Mullen ASC · May 2, 2004

If it's a multi-bladed shutter projection, you can take a spot meter reading of the screen and hold the button down and see what the exposure sort of averages out to be. It helps if the projected image has a gray card at the head, otherwise you have to find an 18% gray reference in the image.

Marty Hamrick · May 2, 2004

Does it change if I convert the projector to a camera type shutter or will the same meter trick work?

Marty

David Mullen ASC · May 2, 2004

No, if you sync a single-bladed projector with a camera shutter, essentially you get twice as much exposure off of the screen on the camera than what you see with your eyes, so you need some kind of flash meter I guess.

Mitch Gross · May 2, 2004

Also note that you are talking about using an Arri S camera, which will not have a crystal sync motor unless you've had it modified or purchased a special new one. So the camera will not run at a precise 24fps and there for your shutter timing with the projector will be all over the place. In practice this is about a 1.5 stop difference in exposure with a common 2 or 3 blade projector, the kind one used to find in a school or municipal setting. So use a spot meter on the screen to guesstimate your exposure and when in doubt over-expose it a little. Your biggest problem will be the light levels you'll be working with. These projectors are not incredibly bright, and if you want to see anything on the screen you will need to light the rest of the shot to a fairly low level and keep as much spill off the screen as possible. Let the projector dictate your exposure as it is the one lamp you really can't control. Shoot with 500 speed stock and make the image from the projector as small as you can get away with narratively so that the image will be it's brightest.

Michael Nash · May 3, 2004

You could also consider compositing the projected image, if the shot is a lock-off. Then you can film at any light level you want (just do me a favor and insist to your editor that the black levels of the projected image aren't darker than the screen it's projected on -- drives me nuts whenever I see that!)

A trick I've learned for balancing exposure between live action and a screen or monitor image is to simply look at the video tap image (or a similar on-set video camera). Basically, if it looks reasonable on the tap it won't look any WORSE on film. Of course you still need to synch the projector and camera.

I've shot Betacam footage of projected 16mm with a double-bladed projector, and had it come out just fine. Of course the light levels were very low.

Marty Hamrick · May 4, 2004

You could also consider compositing the projected image, if the shot is a lock-off. Then you can film at any light level you want (just do me a favor and insist to your editor that the black levels of the projected image aren't darker than the screen it's projected on -- drives me nuts whenever I see that!)
<I just learned that this will be a dolly shot where we need to see the football players in the FG as the coach speaks.So we also may need to see some projected image spill onto the actor.

A trick I've learned for balancing exposure between live action and a screen or monitor image is to simply look at the video tap image (or a similar on-set video camera). Basically, if it looks reasonable on the tap it won't look any WORSE on film. Of course you still need to synch the projector and camera.

Yeah,I pulled that off a few weeks ago doing a story on the Passion of the Christ opening up where I needed to shoot a reporter standup with the screen in the BG,got a slight flicker, and for that purpose,the screen was perfect,the darkness and lack of sharpness actually helped hide the goriness we couldn't show.

I have a new option just presented to me today.For this shot alone,a friend suggested I used his Canon Scoopic(for this shot only) that had been converted to be used to shoot sync with an Optasound cassette deck.For those of you who have no idea what I'm talking about,Optasound was a short lived system that used a sync pulse coming from a pre pulsed tape.The camera was equipped to "slave"to the pulses via a multi pin cable.Tomorrow night I intend to test this by installing a 1 F switch to the projector (basically a magnet attached to the shutter shaft that closes a switch every time the shutter turns and connecting it to the remote/sync input of the Scoopic,thereby "slaving" the camera to the projector.

All sound is to be foleyed and dubbed in so cam noise won't be an issue and there is only about 8 seconds of lip sync in the spot.I'm also having a friend convert the projector with a camera type shutter as I write this so David's flash meter idea sounds doable.

Anyone out there remember Optasound and 1 F switches?

Marty

You could also consider compositing the projected image, if the shot is a lock-off. Then you can film at any light level you want (just do me a favor and insist to your editor that the black levels of the projected image aren't darker than the screen it's projected on -- drives me nuts whenever I see that!)

I thought of that,but the producer/director wants this shot to be a dolly,we need to see football players heads in the FG as the coach paces back and forth,so there also has to be some image spill on the coach(just found that out today and my shoot date is sometime in July, about 6 days before I have to leave for a 3 day shoot to cover one of the conventions in either NY or Boston,forget which),so I may opt for a cheap fix of an all video shoot.But I haven't given up yet.>

A trick I've learned for balancing exposure between live action and a screen or monitor image is to simply look at the video tap image (or a similar on-set video camera). Basically, if it looks reasonable on the tap it won't look any WORSE on film. Of course you still need to synch the projector and camera.>

Right,I thought of that and while I don't have a video tap for the Arri S, I had a friend 'Jerry rig" a cheap vidcam to the VF for such,hell it works.

Phil Rhodes · May 4, 2004

Hi,

Polaroids?

Phil

Marty Hamrick · May 5, 2004

Please elaborate, Phil.

Marty

Phil Rhodes · May 5, 2004

Hi,

Take pictures using an instant Polaroid camera to evaluate exposure.

Phil

Michael Nash · May 5, 2004

Right,I thought of that and while I don't have a video tap for the Arri S, I had a friend 'Jerry rig" a cheap vidcam to the VF for such,hell it works.

Great -- but the video camera doesn't even have to be linked to the film camera optics. It's just a reference for the balance between the projection and the light levels in the room. Then you meter and expose for the room, knowing the projection is within visible range.

Phil suggested Polaroids for this same purpose, but you have no way of ensuring synch between the Polaroid camera and the projection. This is yet another use I've found for my cheap little digital camera (the same one I showed you a couple weeks ago, Phil). Even though you can't synch the camera externally, in preview mode with the LCD you can see light levels in the camera's native scan rate (probably 1/60). It's also got a dynamic range that's more like a film print, compared to a video camera.