Jonathan Wilcox

It refers to point sources only - in infinitesimally small point of light - which no light is... Lights are an integration of many points of light all projecting their own spheres of transmission, creating a kind of 3 dimensional offset paths to fuddle up your dinner party arguments.

 

But all lights tend towards point sources the further you get away from them, and you don't need to be too literal with it as the adjustment required to get it right is both waaaaaay too complex to figure out and also well within the range of errors conjured up by every other factor involved.

 

But yes, if you are very close to a large wall of very bright end even diffusion the inverse square law will not apply so perfectly.

Yeah makes a lot of sense. I was doing a test with a light meter and a large soft source and the numbers were way off from the inverse square law equation.

Does the inverse square law apply to all lights? Including diffusion panels, chimeras, fresnels, pars, source 4, natural daylight coming from a window, etc.?

Does the law change at all when dealing with lights such as Pars (that are supposed to have longer throw capabilities?) What does 'throw' have in relation to inverse square law.

And in what situations would you use a light with more throw and in what situations would you use a light with less throw?

Thanks Guy, you are an amazing resource of information.

Excellent advice Ron.

Is it possible to exchange electronic ballasts - for example, using arri electronic ballast with ltm light, or strand ballast with arri light, etc.?

What are some precautions to take when using electronic ballasts? I am quite familiar with magnetic but have not yet used electronic ballasts.

So I have a short film that is 'in talks'. Likely it will never come to fruition, but just in case I thought I would ask what you guys think would be the best way to light the end shot.

 

Essentially there are a couple of gangsters in a bar talking, then eventually they pull guns on each other. It cuts to exterior (Night) and you are supposed to see the muzzle flashes in the windows. Just to clarify, you won't be seeing any actors or the guns or actual muzzle flare through the windows. Just the room lighting up due to the muzzle flare.

 

How would you do it?

This can be done very simply and effectively using dimmers.

The New World is, as far as I know, all natural lighting.

I love how natural the work of Harris Savides and Lance Acord are. They don't use all natural light but they effectively augment natural light with movie lights.

If you haven't read the book New Cinematographers yet, it is an excellent read.

Also check out this interview

http://www.createasphere.com/En/panels/item/14-lance-acord-asc-and-jon-witmer-associate-editor-at-american-cinematographer.html

And check out these podcasts:

http://www.theasc.com/ac_magazine/podcasts.php