adjusting lights from shot to shot

C

chand

New member
Hi,

I've seen many DPs adjust the lights when they went from wide shot to medium shot and then from medium shot to close up. I know they do that to make every shot look good. However I forgot what ways they adjust the lights to make every shot look good.

Can someone please tell me the different ways DPs adjust the lights in order for the each shot in a scene to look good.


Thanks a million
 
Often times, the look goes from harder (i.e. contrasty) lighting in wide shots (it is more interesting and makes the environment look better) to softer, diffused lighting in the close ups (to make the actors look good).
 
But in order to make every shot look the way they want, would DPs add a light or remove a light?
What I mean is, for example, in the medium shot everything looks good. But then in the close up would DPs add a light or remove a light in order to make that close up look good too?
 
Depends on every situation, your answer comes from experience and the specifics of each shot.

However light falloff dictates that as distance doubles the intensity halves, therefor the longer the shot the more light you will need overall (if you intend to keep the lights out of the frame)...
 
seejay1031 said:
Depends on every situation, your answer comes from experience and the specifics of each shot.

However light falloff dictates that as distance doubles the intensity halves, therefor the longer the shot the more light you will need overall (if you intend to keep the lights out of the frame)...
Click to expand...

Not quite. I was under the impression that light falloff was part of the Inverse Square Law, which is when the distance doubles the light decreases by 1/4th, not 1/2.

Some units have slightly more falloff then others.... and I'm assuming it's based off of the quality of reflector, lamp housing, and lens. I think fresnels are the most consistent because of the way the lens smooths the spread and focus of the light. My assumption.

To check this, before I run out the door:

Kino Flo 4 Bank (Tall Boy):
@ 4 feet: 173 foot candles
@ 8 feet: 49 foot candles

Mole Richardson 10" Fresnel 2k Junior Solarspot (at full flood):
@ 10 feet: 440 footcandles
@ 20 feet: 110 footcandles

Mole Richardson Par (64w Medium Flood globe openface):
@ 10: 340 footcandles
@ 20: 85 footcandles
 
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Ryan, based on your data, you might have wanted to describe it as "decreased *to* a quarter" rather than "by a quarter". Or perhaps "by three quarters". Sorry to be picking nits : )

Interesting data btw...thanks!
 
Ted Spencer said:
Ryan, based on your data, you might have wanted to describe it as "decreased *to* a quarter" rather than "by a quarter". Or perhaps "by three quarters". Sorry to be picking nits : )

Interesting data btw...thanks!
Click to expand...

Yeah, I was racking my brain on a good way to word that... I could say "to 1/4", but that isn't entirely clear. Saying by three-fourths would probably make people think it was a factor of 1/3... No easy solution.

I guess
2 X Distance = 1/4 X Amount of Light
Click to expand...
works best.

Or in the context of trying to reach a specific stop,
Doubling the distance between light and subject will reduce that light by two stops.
Click to expand...
(Although the spread of the light will be very large)

For those curious, the reason the inverse law exists is because the farther the light is, the more the spread of the light, causing the light to fall over a greater area hence not being as intense.

Another factor is atmosphere. If you are shooting a light through fog, haze, smoke, or etc... be prepared for the light intensity to fall off much faster then by the inverse square law.
 
seejay1031 said:
However light falloff dictates that as distance doubles the intensity halves
Click to expand...

This is correct, what you're forgetting is that the light is making a round trip. Half as much light makes it from the lamp to the subject. Then half of that light makes it from the subject to the camera.

so (1 / 2) /2 = .25
 
The inverse-square law applies to light reflected from your subject, as well as any other light from any other source.
 
Sad Max said:
The inverse-square law applies to light reflected from your subject, as well as any other light from any other source.
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Nope.

Camera to subject distance has nothing to do with exposure nor the Inverse Square formula which determines the lighting 'falloff'.

The exception: Only when shooting a great distance through atmospheric haze (whatever the form) will a camera's distance effect exposure/ lighting on a subject.
 
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Somehow it seems odd that light reflected from a body follows different physical laws than light emitted from a source...
 
Sad Max said:
Somehow it seems odd that light reflected from a body follows different physical laws than light emitted from a source...
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Damn good question and after an hour or so trying to explain this (and poorly) to my sister who is a science teacher, I actually came up with this theory:

It's because we see reflected light. In a way, whatever we are looking at is the light source.

It's a strange concept, but true.

Think about a Kino Flo. When it's really close to you, it gives off more light intensity then when it's far away. But when you look at the actual light, it's 'brightness' is the same whether it is close to you or far away.

So when we see a car on the street, we automatically couple the idea that the sun is the source of light. The reality is that electromagnetic waves of energy are passing by and the car is sending us reflected light which allows us to see the car.

So, despite the fact the Sun is technically the source of the electromagnetic energy which allow illumination to occur... the car becomes and is the new source from which the light is coming from. Looking at the car is really looking at the source.

Just as in filmmaking, when you bounce a light or put it through diffusion, the light source 'changes' from the light unit to the bounceboard/diffusion paper/silk.

So the basic and key difference is that we are looking at the source. In the Inverse Square Law, the reason for diminishing intensity is because the surface area of the light increases. When looking at a lighting source, the surface area of the falling light becomes unimportant. Human eyesight and cameras see reflected light, and as proven, the object upon which the light is being reflected becomes the source. We are looking at 'sources'.

That's my best explanation, anyhow.
 
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This doesn't seem to indicate that light rays traveling from a bounce board or through the diffusing medium are immune to the inverse-square law, any more than light rays traveling from the kin-flo source are...
 
Sad Max said:
This doesn't seem to indicate that light rays traveling from a bounce board or through the diffusing medium are immune to the inverse-square law, any more than light rays traveling from the kin-flo source are...
Click to expand...

Light rays on a bounce board and through diffusing mediums are definitely subject to the Inverse-Square Law.

It's the fact that we are looking right into the source when we see things. There is no increase or decrease in surface area, because we are not looking at the results of the light. We are looking at the source. And since objects which reflect light 'become' the source, we see everything (that we see) as a source.
 
When looking directly at a source, it's surface area is defined. A white light bulb will always be the same intensity, no matter the distance we see it from, because it's always 60w of light hitting the same surface area of the bulb.

When looking at lighting sources, they are immune to the inverse-square law, because they have fixed surface areas. And all light we see is reflected light, therefore the objects become the sources.
 
I don't see that any of the above is relevant to the observation that the inverse-square law applies to light scattering off your subject as well as light radiating from an emitter. Reflected radiation measured one millimeter from the surface of a mirror will be more intense than that measured at ten kilometers.

I expect I'm missing something.
 
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The most important law to remember when adjusting lights is: light adjustment + Christian Bale = "Ohhhh goooood for you!"
 
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