Fluo equivalence at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Photon Management

Photon Management
Shine an ever-loving light on you.


Reply
 
Thread Tools Search this Thread
Old October 3rd, 2007, 05:55 AM   #1
Trustee
 
Join Date: Sep 2005
Location: Rio de Janeiro
Posts: 1,225
Fluo equivalence

Hi,

I've been looking into some daylight kits and I saw one that carried 4 30w fluorescent ligth bulbs. I have read somewhere that a 30w fluorescent light is equivalent to about 150w regular. Is this right? Because in this case a set of 4 30w fluo light bulbs (total of 120w) would be equivalent to 600w, which is actually good.
Rafael Lopes is offline   Reply With Quote
Old October 3rd, 2007, 03:45 PM   #2
Major Player
 
Join Date: Apr 2006
Location: New York
Posts: 204
It is my understanding that fluorescent light is 4 times as efficient as tungsten. That is, multiply the wattage of the flo by 4 and you get the comparative tungsten output. So, each one of your 30W flo bulbs will be putting out the equivalent of 120W tungsten. All four would be equivalent to 480W.

I'm not an expert in photometrics, so it would be best if someone (Richard of Cool Lights?) could verify my response.

~~Dave
Dave Dodds is offline   Reply With Quote
Old October 3rd, 2007, 06:35 PM   #3
Trustee
 
Join Date: Nov 2005
Location: Honolulu, HI
Posts: 1,961
Richard has pointed out that compact fluorescents are not as efficient as externally ballasted fluorescents. You might want to use 3x for compact fluorescents instead of 4x the efficiency of tungsten. The real benefit comes if you are trying to match daylight. The huge loss of using a full CTB blue filter in front of tungsten really makes fluorescent a better choice. That 120W of daylight fluorescent will be stronger than 650W of tungsten in daylight. If you really want to have strong daylight fixtures, look into the ones that have separate ballast and PL55 (55Watt) tubes. They are bright and reasonably compact.
Marcus Marchesseault is offline   Reply With Quote
Old October 3rd, 2007, 10:17 PM   #4
Major Player
 
Join Date: Jun 2006
Location: Shenzhen, China
Posts: 781
Yes to be conservative, I would say 3 times then your expectations are set such that you won't be disappointed if the CFLs you choose don't seem as bright as you'd hoped.
__________________
Richard Andrewski - Cool Lights USA - RED #114
http://www.coollights.biz
Richard Andrewski is offline   Reply With Quote
Old October 4th, 2007, 12:37 AM   #5
Trustee
 
Join Date: Sep 2005
Location: Rio de Janeiro
Posts: 1,225
Thanks, guys. This information helps a lot.
Rafael Lopes is offline   Reply With Quote
Old October 8th, 2007, 07:21 AM   #6
Major Player
 
Join Date: Oct 2006
Location: West Africa
Posts: 255
Better still, just take note of the number of rating in lumens.
Seun Osewa is offline   Reply With Quote
Old October 12th, 2007, 01:21 PM   #7
Major Player
 
Join Date: Mar 2007
Location: Wurzburg, Germany
Posts: 316
Be careful with household fluorescents. I recently bought a 25Watt fluorescent bulb that said "daylight". It is relatively bright, but the cri of this lamp is more than bad. The light is very blue (at least 7000K I guess) but it lacks a lot of wavelengths. It looks very blueish and it is bright, but you don't see very well with it. It's a light I wouldn't want anywhere in my home...
You can use it as a daylight fill, but as your only light source it's worthless.
Heiko Saele is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Photon Management

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 03:08 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network