shooting in a home cinema to include the projected image at DVinfo.net

Michael Donne · September 8th, 2008, 03:57 PM

Hi

I have to shoot a home cinema room and some of my footage will need to include a guy talking while behind him a movie is playing silently on the screen. I am concerned about how to capture the image from a DLP projector.

Am i right in thinking if its single chip i'm stuffed but if its 3chip i'm ok? (it's a very top end home cinema, thats all i know).
I'm in PAL so do I stick to 1/50 shutter?.....should i choose to play a movie with very slow action preferably (the guy talking will be pretty static...i know i need to light him with v little spill onto the movie screen).

Any wisdom greatly appreciated as my searches havent turned up much.
Thanks.

Michael

Kurth Bousman · September 8th, 2008, 08:34 PM

It sounds like you are going to rear project the image , otherwise the figure also has the projected image overlaying it , which can be cool too. I think I would do some testing . I've done this but my projector was just 60i out and that's what I was filming . Now there are so many other projection and filming possibilities . My experience was, it's easy except exposure . Expose for a backlit image , otherwise the figure will be dark .k

Dylan Pank · September 10th, 2008, 09:19 AM

1 chip/3 chip won't make much difference beyond the same quality issues that ALWAYS affect 1 vs. 3 chip cameras.

You basically need to expose for the screen and then light the face to match that, or really have the background image SLIGHTY duller than your foreground subject. You might want to figure out the colour balance of the projected image. I know CRTs tend to be around Daylight balance, but have not worked with projected images in the same way.

Yes stick to 50i and make sure the playback image is also 50i or 25p. Make sure it's not a 29.97 FPS video or you'll get awful flicker.

The speed and activity of the image in the background depends on how distracting you want the background to be. You might want to try to reduce the DOF (exposure & focal length allowing) so the background softens a bit, tricky with a 1/3" chipper like the Z1. You could just know the DLP out of focus to simulate, but if the edges of the screen are in shot, it will be obvious that the image is out of focus rather than a shallow DOF.

Boyd Ostroff · September 10th, 2008, 12:14 PM

Quote:

Originally Posted by Dylan Pank

1 chip/3 chip won't make much difference beyond the same quality issues that ALWAYS affect 1 vs. 3 chip cameras.

Well I assumed that Michael was talking about 1 vs three chip projectors instead of cameras. The higher end DLP projectors have 3 chips while the cheaper ones have one with a rotating filter wheel.

I suspect that won't be much of an issue though. We use large screen video projectors for our operas sometimes (got a big one coming up with two 10,000 lumen and one 20,000 lumen DLP projectors now). I shoot our archive videos with a Z1 and haven't seen any issues with filming the projections. Since the image isn't "scanned" like a CRT, you shouldn't have any of those sync problems. I always shoot 60i with a 1/60 shutter speed.

For me, the biggest issue is that it's impossible to white balance correctly in a situation where you have a projected image with a Xenon or HMI lamp and tungsten from the stage lighting. You're pretty much stuck with either making the projections too blue or the stage lights too orange. I've played around with color correction in post to help this, but it's still a problem.

However, if you can control everything for your shoot you should be able to use light sources close to the projector's color temperature.

Vito DeFilippo · September 11th, 2008, 07:53 AM

If it's a locked down shot, it would be very easy to add in post. You might find that will simplify your shoot.

Michael Donne · November 5th, 2008, 05:02 PM

Apologies to all for a slow response to all your kind suggestions. I was waiting to be able to give my own feedback based on how things turned out but there was a delay in the project. Anyway, it was a 3 chip projector and presented no problems, at least that i could discern, regardless of the motion on screen.
Thanks.

September 8th, 2008, 03:57 PM	#1
Michael Donne Regular Crew Join Date: Feb 2005 Location: brighon uk Posts: 55	shooting in a home cinema to include the projected image Hi I have to shoot a home cinema room and some of my footage will need to include a guy talking while behind him a movie is playing silently on the screen. I am concerned about how to capture the image from a DLP projector. Am i right in thinking if its single chip i'm stuffed but if its 3chip i'm ok? (it's a very top end home cinema, thats all i know). I'm in PAL so do I stick to 1/50 shutter?.....should i choose to play a movie with very slow action preferably (the guy talking will be pretty static...i know i need to light him with v little spill onto the movie screen). Any wisdom greatly appreciated as my searches havent turned up much. Thanks. Michael

September 11th, 2008, 07:53 AM	#5
Vito DeFilippo Trustee Join Date: Mar 2006 Location: Montreal, Quebec Posts: 1,585	If it's a locked down shot, it would be very easy to add in post. You might find that will simplify your shoot. __________________ . http://www.nosmallroles.com

September 8th, 2008, 08:34 PM	#2
Kurth Bousman Major Player Join Date: Apr 2004 Location: san miguel allende , gto , mexico Posts: 644	It sounds like you are going to rear project the image , otherwise the figure also has the projected image overlaying it , which can be cool too. I think I would do some testing . I've done this but my projector was just 60i out and that's what I was filming . Now there are so many other projection and filming possibilities . My experience was, it's easy except exposure . Expose for a backlit image , otherwise the figure will be dark .k

September 10th, 2008, 09:19 AM	#3
Dylan Pank Major Player Join Date: Nov 2004 Location: Portsmouth, UK Posts: 611	1 chip/3 chip won't make much difference beyond the same quality issues that ALWAYS affect 1 vs. 3 chip cameras. You basically need to expose for the screen and then light the face to match that, or really have the background image SLIGHTY duller than your foreground subject. You might want to figure out the colour balance of the projected image. I know CRTs tend to be around Daylight balance, but have not worked with projected images in the same way. Yes stick to 50i and make sure the playback image is also 50i or 25p. Make sure it's not a 29.97 FPS video or you'll get awful flicker. The speed and activity of the image in the background depends on how distracting you want the background to be. You might want to try to reduce the DOF (exposure & focal length allowing) so the background softens a bit, tricky with a 1/3" chipper like the Z1. You could just know the DLP out of focus to simulate, but if the edges of the screen are in shot, it will be obvious that the image is out of focus rather than a shallow DOF.

November 5th, 2008, 05:02 PM	#6
Michael Donne Regular Crew Join Date: Feb 2005 Location: brighon uk Posts: 55	Apologies to all for a slow response to all your kind suggestions. I was waiting to be able to give my own feedback based on how things turned out but there was a delay in the project. Anyway, it was a 3 chip projector and presented no problems, at least that i could discern, regardless of the motion on screen. Thanks.