Jump to content


Photo

Illumination calculation


  • Please log in to reply
1 reply to this topic

#1 Alain J Francois

Alain J Francois
  • Basic Members
  • PipPip
  • 10 posts
  • Cinematographer
  • Australia

Posted 09 July 2006 - 10:22 PM

The answer to this question seems to elude me in a most vexing way.
Given a desired aperture (say T/5.6) and an ASA rating (say 125), I know how to calculate the required FootCandles - answer 200 Fc.
What I would like to know is how to calculate the amount of lamps, given the known wattage of each lamp required to produce that amount of 200 Fc. (I do realise that it is a mistake to consider wattage as output - it is a measure of lamp consumption), however there must be some calculation or simple relationship that would allow me to estimate the amount of lamps I am going to need for a particular scene. :unsure:
  • 0

#2 Michael Nash

Michael Nash
  • Sustaining Members
  • 3330 posts
  • Cinematographer
  • Pasadena, CA

Posted 09 July 2006 - 11:50 PM

The output of any given lamp can vary wildly depending on many variables, like par vs. fresnel; flood vs. spot; clean vs. diffusion; efficiency of the reflector; age of the bulb; and so on.

There's no practical way to calculate this. What you do instead is get familiar with the behavior and quality of the different lamps, and make an educated choice when to employ them.

You can look up the photometrics (light behavior) of many lamps in the book, Set Lighting Technician's Handbook, and sometimes on the websites of the lamp manufacturer.
  • 0


Paralinx LLC

Technodolly

rebotnix Technologies

Glidecam

Media Blackout - Custom Cables and AKS

Abel Cine

Willys Widgets

FJS International, LLC

New Pro Video - New and Used Equipment

CineLab

Gamma Ray Digital Inc

Broadcast Solutions Inc

The Slider

Aerial Filmworks

Visual Products

CineTape

Rig Wheels Passport

Metropolis Post

Wooden Camera

Tai Audio

Ritter Battery

Broadcast Solutions Inc

Metropolis Post

Abel Cine

New Pro Video - New and Used Equipment

The Slider

Gamma Ray Digital Inc

Technodolly

Rig Wheels Passport

rebotnix Technologies

Visual Products

Willys Widgets

Glidecam

CineLab

FJS International, LLC

Ritter Battery

Wooden Camera

Tai Audio

Aerial Filmworks

Paralinx LLC

CineTape

Media Blackout - Custom Cables and AKS