Lighting Ratios and Lighting Digital vs. Film

[youandi]

Hi Everyone ...

My question is what is the basic difference between lighting digital film and celluloid film? What does the light ratio mean? Is it a ratio of key light and fill light in K? If yes then what ratio will be perfect for filming a set up based sitcom?

Please describe the detail and well how much it matters with the distance if your set is with less space, what should the distance of light source be? How much K generally cover how much space?

To give it a natural look I want background shades and lights (bulbs, candles) be natural so what should be the ratio of background light in comparison to key light?

Please let me know

 

[vervor]

Lighting for film and digital can be very different but often it's more similar than people think... lighting ratio is key+fill:fill - most things are done 2:1 or 4:1 - and prob 95% of sitcoms are in that range - that converts to 1-2 stop difference for the lighting ratio

If you're shooting film you probably want to keep in mind more "rules" and techniques but digital is, to me, much more free, and you should really just keep an eye on your monitor and make it look good - remember, low light in digital is low quality and it's okay to overexpose and then darken it later so that you've got all the detail natively. - be more specific about what you're shooting though and then we can get more specific about advice...

 

[David Mullen ASC]

There is no such thing as "digital film".

There is no such thing as digital or video lighting and film lighting. There is only LIGHTING. Period. You want a room to look like it was lit by a setting sun outside the window or a candle on the dresser, you do almost the same things whether using film or digital. You want to make an actress look thinner or younger, you do the same things. You want to make the image look like a Vermeer or Rembrandt, you do the same things. You want to make your movie look like "The Godfather", you do similar things.

Different video cameras and different film processes have different contrast and exposure ranges, so you make ADJUSTMENTS in the lighting for those qualities. Reversal film has a different contrast than negative film. Skip-bleach processed negatives or prints change the contrast. So it is not really a digital vs. film issue. It's just about understanding what a particular film stock, process, digital camera, etc. does differently and making adjustments for that. But the overall concepts of lighting are the same.

Digital cameras have less exposure range in the bright highlights, so the main difference compared to color negative will be in how fast bright areas will burn out and "clip". Luckily since with video you can SEE the results right there when you shoot it, you can adjust the brightness of lamps or windows by looking at the monitor, etc.

I don't find in terms of fill light for shadows that I do much differently for video or color negative. Of course, when I'm shooting digitally it tends to be with pro HD equipment, which has a little more exposure range than a consumer DV camera.

"K" refers to "Kelvin", the color temperature of a light. Tungsten is 3200K and photographic daylight is 5500K.

"Lighting ratio" is a ratio between the key and fill. If the fill is one stop darker than the key, i.e. half the amount of light in the shadows, that is a 2:1 ratio (which is rather flat, lighting-wise.) I don't calculate things in terms of ratios because it's pointless to make such a calculation if you are lighting in terms of f-stops (makes more sense if you are lighting in terms of footcandles though.) I simply decide how many stops darker than the key I want the shadows to be when lighting (often three stops darker, for example.) But more than often, I set the amount of fill by eye and don't bother metering it. Especially when shooting digitally when I can SEE right there how the fill looks.

 

[youandi]

more questions?

more questions?

Well first of all thanks for your replies Mr. Vervor and Mr. Mullen ... Being more specific as Mr. Vervor wanted to know it's a sitcom one like British sitcom Three's Company ... we have created the set of apartment and there is no source of natural light ... if you won't give light it's as dark as no moon night ... well definitely it's better to use more light to have quality as you have mentioned but I want to know the ratio between key light and fill light ... Normally here in Nepal these light men don't create much difference between key light and fill light ... they want everything glowed in the process so it doesn't give any shade at all ... hope you understood what I'm referring to ... so what should be the criteria... how much K should be used as basic light and how much as fill?
Definitely the most appropriate way to see the lighting is viewing it in monitor ... as Mr. Mullen described but at few times it appears right in front of monitor and when we were trying to digitally enhance it we found color burnt? Is it because of inefficiency of Camera man or because of light?

We shoot our project in SONY 370

Thanks again

 

[David Mullen ASC]

I don't really understand your question, sorry.

 

[Agenda Productions]

low light in digital is low quality and its okay to overexpose and then darken it later so that you've got all the detail natively. .

Is this true? I was reading today an independent filmmaking book and they said quite the opposite.
"When working with film try and overexpose it one stop"
&
"When working with video try and underexpose it one stop".

Why not expose it correctly? Anyway it brings up a thought after reading this post.

James.

 

[David Mullen ASC]

Film and video exposure is all about placing information within a range that the medium can capture and in a manner that will give you the look you want.

Video tends to be weaker in holding highlight detail than shadow detail, hence why one might tend to slightly underexpose, or at least, favor highlight information at the expense of shadow information.

But in a low-key situation with a lot of dim, murky detail that you want to hold and not get a lot of noise, it might make sense to not underexpose that too much and darken it later in post to the degree desired, because you will pick up noise if you end up having to slightly lift the image in post because you're trying to bring out shadow information.

In other words, it tends to be a good idea to play it safe with film and video and expose as much information as you can and then darken it the rest of the way in post. Within limits. If you want a very dark day-for-night effect where you plan on underexposing by three stops, you don't want to shoot completely normally either. You may want to underexpose by two stops, for example, and darken it the rest of the way in post. Same for the amount of blueness -- you may want a half-blue look and add the rest of the blue in post to taste. Too heavy a blue or too much underexposure in the original photography and you have recorded less information to work with. Too little and you may have to make too radical a change in post and pick-up some artifacts from pushing the recording so far in one direction.

Film negative tends to favor some mild overexposure because it produces a denser negative that when printed down (at higher printer lights) tends to produce deeper blacks, snappier contrast, tighter grain, and richer colors. You can get away with that because of negative's latitude in holding onto bright details.