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High Speed Projectors


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#1 Zachary Van Heel

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Posted 31 May 2016 - 09:39 PM

Hello, 

 

I have been trying to research with little success on using projectors and high frame rates.

 

I want to shoot 96 fps. With a projected image in frame.

 

Would an LED projector allow filming at different frame rates/ shutter speeds without having flicker?

 

And also having to consider output of the actually unit to get an image exposed when going to the higher frame rate.

 

Or if anyone has worked with a specific projector that they recommend would be great or any good resources on this would be awesome, I have come up fairly empty handed and talking with some local projector rental companies to no avail.

 

Thanks in advance

Zach


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#2 Tyler Purcell

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Posted 31 May 2016 - 10:00 PM

What's an LED projector?

Anyway, there are 120FPS projectors out there...

https://www.barco.co...f25817f/F50.pdf
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#3 Zachary Van Heel

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Posted 31 May 2016 - 10:43 PM

What's an LED projector?

Anyway, there are 120FPS projectors out there...

https://www.barco.co...f25817f/F50.pdf

 

 

Using an LED light as the source instead of a standard bulb, regardless of being reflective (DLP) or transmissive (LCD). If it would allow for higher frequency. 

 

Thank you for the reply. Have you had experience filming with this projector/ a projector at higher frame rates?


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#4 David Mullen ASC

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Posted 31 May 2016 - 11:12 PM

If you are in Los Angeles, I recommend visiting VER in Burbank, who has a large selection of projectors to choose from.

 

I went over there to test a DLP projector playing back a Quicktime clip from my laptop, using my little Sony NEX6 camera to shoot 24P video of the screen image... had sync issues even though the clip on my laptop was also shot on the same Sony camera at 24P, but I think the HDMI out was a 60i signal.  Anyway, VER suggested I try an LCD projector and I had no sync issues.

 

So if you can get a digital camera that runs at 96 fps and set-up a test at a video projector rental house, you might be able to find something that works.

 

http://www.verrents....lcd-projectors/

 

In terms of brightness, I ended up renting a 15,000 lumens LCD projector to fill a 12'x8' screen -- I was able to shoot at T/2.0 at 200 ISO on a 35mm film camera loaded with 250D stock.  That should give you some idea of what you'd get on an 800 ISO digital camera -- which at 96 fps, would be like 200 ISO at 24 fps.


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#5 Tyler Purcell

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Posted 31 May 2016 - 11:40 PM

Using an LED light as the source instead of a standard bulb, regardless of being reflective (DLP) or transmissive (LCD). If it would allow for higher frequency.


Ahh got ya. TO me, when someone says LED, I think of a display device, rather then a light source.
 

Thank you for the reply. Have you had experience filming with this projector/ a projector at higher frame rates?


Ohh I don't know anything about it, I just did a google search and came up with an answer. ;)
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#6 Zachary Van Heel

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Posted 01 June 2016 - 05:23 AM

If you are in Los Angeles, I recommend visiting VER in Burbank, who has a large selection of projectors to choose from.

 

I went over there to test a DLP projector playing back a Quicktime clip from my laptop, using my little Sony NEX6 camera to shoot 24P video of the screen image... had sync issues even though the clip on my laptop was also shot on the same Sony camera at 24P, but I think the HDMI out was a 60i signal.  Anyway, VER suggested I try an LCD projector and I had no sync issues.

 

So if you can get a digital camera that runs at 96 fps and set-up a test at a video projector rental house, you might be able to find something that works.

 

http://www.verrents....lcd-projectors/

 

In terms of brightness, I ended up renting a 15,000 lumens LCD projector to fill a 12'x8' screen -- I was able to shoot at T/2.0 at 200 ISO on a 35mm film camera loaded with 250D stock.  That should give you some idea of what you'd get on an 800 ISO digital camera -- which at 96 fps, would be like 200 ISO at 24 fps.

 

 

Thanks for the reply David.

 

In Philadelphia, so so far looking like I will need to do a test day up in New York as I can't seem to find any rental houses that are outside the corporate business meeting model here with multiple options. 

 

Would you off chance know the distance of the projector to screen to for the 15,000 lumens LCD projector? Or a guesstimation.


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#7 JD Hartman

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Posted 01 June 2016 - 06:15 AM

 

In Philadelphia, so so far looking like I will need to do a test day up in New York as I can't seem to find any rental houses that are outside the corporate business meeting model here with multiple options.

VER also has a location in Seacacus, NJ.    http://www.verrents.com/


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#8 David Mullen ASC

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Posted 01 June 2016 - 07:14 AM

Maybe 15'? It was a faster wide-angle-ish prime lens on the projector which helped for output.
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#9 Shawn Sagady

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Posted 02 June 2016 - 11:38 PM

When you are dealing with higher end projectors they, like cameras, have a wide variety of lenses to handle various distances.  The widest reasonable lens used for those types of projectors is typically around 0.8:1 ratio.  Which indicates every 0.8 units from the lens the image becomes 1 unit wider.  You can apply this to meters or feet or what ever.  The wider lenses like 0.8:1 often have a bit of fish eye effect to them in the corners so your millage may vary, its not usually to extreme though. 

 

Keep in mind the effectiveness of a 15k Lumen projector is variable based on the size of the image you are projecting, just like with any kind of light there is exponential fall off based on area.  So if we know that David was using a 15k projector on a 12'x8' screen his foot candles were (15000 / 96) = 156.25 or (Lumens / Sqft) = fc.  So to achieve a similar level of light you would simply solve based on that equation, once you know the size of the surface you can do Sqft * fc = Lumens.  There are always other variables like the gain of the screen and its transmission properties or color etc, but this should get you in the ball park.

 

David DLP projectors tend to be fixed to 60i/p due to the nature of the mechanism and to avoid color flickering, especially with single chip systems that use color wheels.  LCD projectors are much more flexible but tend to have more washed out colors and much lower contrast.

 

Hope some of this information was helpful, but like with any project I really recommend doing some camera tests.  


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