Ambient light measurement standards - Home Theater Forum and Systems - HomeTheaterShack.com

 
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post #1 of 4 Old 04-20-15, 01:07 PM Thread Starter
A J
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Ambient light measurement standards

All,

I measured the light hitting my potential screen position with my windows open (measured in direction of proposed projector position) and get a consistent 5 lux.

5 lux = .46 footcandles
5 lux = .47 footlamberts

My proposed usage is an Epson 3050 from 11.5ft onto 100" diagonal.

Using the Projector Central calculator and a 1.0 gain screen shows an image brightness of 30 foot lamberts.

If ambient light occurs from the side, shouldn't the vast majority of the light just 'skip' off (angle of incidence = angle of reflection ...) ?

I always try to over analyze things and really need to fully understand ambient light and measurements.

What measurements etc. can I take to better quantify my living room as a projector/screen location?

Thanks in advance,
AJ

Epson 5030UBe (118" DIY screen)
Marantz sr6010 amp
Theil CS .5 front speakers
REL Storm SubWoofer
Polk Audio Center Channel Speaker (CS 350)
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post #2 of 4 Old 04-20-15, 05:53 PM
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Re: Ambient light measurement standards

If you have already measured the incident light (5 lux), job is done!
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post #3 of 4 Old 04-20-15, 06:01 PM Thread Starter
A J
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Re: Ambient light measurement standards

Quote:
Yiannis1970 wrote: View Post
If you have already measured the incident light (5 lux), job is done!

Great, just curious if that is the right approach (aiming from screen location toward projector to) or should I aim at the windows each direction to measure the light?

Thanks,
AJ

Epson 5030UBe (118" DIY screen)
Marantz sr6010 amp
Theil CS .5 front speakers
REL Storm SubWoofer
Polk Audio Center Channel Speaker (CS 350)
Definitive rear channels
A J is offline  
 
post #4 of 4 Old 04-21-15, 02:24 AM
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Re: Ambient light measurement standards

Although i believe would make the slightest difference because the light is being reflected from wall to wall into your room, let's say the proper way to do it is to aim your luxometer directly against the primary source of light. In other words, from the screen position you can aim directly your windows.
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