Ambient Light Question.... - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 2 Old 05-06-2007, 09:50 AM - Thread Starter
Senior Member
 
rumonkey2's Avatar
 
Join Date: Apr 2006
Posts: 266
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
...when using ProjectorCentrals Calculator....
I'm no good when it comes to "visualizing" lumens/fc/candlepower/etc...
Am I right in thinking that "room size" plays a key factor in lumens vs. fc? (Not from a throw standpoint, but let's say a 60w bulb in a 20x30 room vs 10x20 room)
So, given my room - 12x12 darkened except for a 60w lamp - what % or fc would that present??? Does this make any sense?
Can anyone simplify this - I've searched & read many articles on light output, and for some reason, can't put the "calculations" into practice....


I saw a simple calculation as fc = lumens/sq feet.....
But, why wouldn't it be cubic ft??? I mean, light is not 2 dimensional??

"I'm a fleabit peanut monkey - all my friends are junkies..."WAR DAMN EAGLE!!!
rumonkey2 is offline  
Sponsored Links
Advertisement
 
post #2 of 2 Old 05-06-2007, 06:14 PM
AVS Club Gold
 
nigel_ht's Avatar
 
Join Date: Sep 2000
Location: Maryland, USA
Posts: 1,640
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by rumonkey2 View Post

...when using ProjectorCentrals Calculator....
I'm no good when it comes to "visualizing" lumens/fc/candlepower/etc...
Am I right in thinking that "room size" plays a key factor in lumens vs. fc? (Not from a throw standpoint, but let's say a 60w bulb in a 20x30 room vs 10x20 room)
So, given my room - 12x12 darkened except for a 60w lamp - what % or fc would that present??? Does this make any sense?
Can anyone simplify this - I've searched & read many articles on light output, and for some reason, can't put the "calculations" into practice....


I saw a simple calculation as fc = lumens/sq feet.....
But, why wouldn't it be cubic ft??? I mean, light is not 2 dimensional??

Its a function of distance and the inverse square law. Its not cubic feet because you care about light on a surface (like say your screen).

What ambient light is on your screen in a 12x12 room depends on how close that 60w light is to your screen and which way its pointing (unless a bare bulb shining in all directions). Then you have to consider what color your walls are for reflections.

Figure that your 60w bulb is 800-900L (call it 65 candela if I remember the conversion right) and figure out the distance and plug into formula.

fc = cd / d^2 so for 12 feet it is 65 / 144 = .45 fc

Hmmm...I should google that to be sure since I did that from memory. Probably did something wrong.

Nigel
nigel_ht is offline  
Reply Digital Projectors - Under $3,000 USD MSRP

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off