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Metering on set procedure: choosing a correct ISO


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#1 Duca Simon Luchini

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Posted 05 August 2016 - 01:55 AM

Hallo everybody,

I am introducing myself on "metering" world... :blink:

 

Reading some articles on web, I found this the should be pretty good to start:

 

http://www.sekonic.c...a-location.aspx

 

I have a Sekonic L-308DC (I always wogk with DSRL or Digital cameras, unfortunately not with film stock).

 

Many article suggest to make a Lighting location scouting to measure the lighting of the stage: in short, to measure the light intensity of the light sources present in the location. In daily outdoor locations we can measure the natural light sources (sun) intensity in the moment we intend to film the scene. In outdoor night locations we can measure the natural light sources ( moon.... fires, candles, bonfires... ) or artificial lighting (street  lighting, urban lighting....).

 

The problem is to set up a right ISO mode. We should be know which ISO value we (or the DP) intend/s to use for that scenes.

But how we can decide it and when?

I mean, when we (or the DP) are/is on location, we/he have/has to decide which will be the ISO value?

I know we should be remain always in a value from 100 ISO to 320 for Daily outdoor scenes, and at most up to 800 ISO, for indoor and night scenes to avoid noise. Of course, we needs light, we have to add instead to increasing ISO value. 

So, are these the basic rules to choose the correct ISO value to use?

 

Many thanks for a reply! :)

 

 

 


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#2 David Mullen ASC

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Posted 05 August 2016 - 11:15 AM

The cinematographer will measure the natural light levels on location during a scout knowing what the fastest stop of the lens they will be using and if they want to shoot wide-open.

 

But let's say you scout a location and it says you need to shoot at f/2.0 (if that's what you are limited to) at 3200 ISO and you plan on limiting yourself to 800 ISO.

 

You either have to add 2 more stops of light or get an f/1.4 lens and add one more stop of light, or compromise and shoot at f/2.0 at 1600 ISO. You may decide to cheat a little and open the shutter from 180 degrees to 240 or 270 degrees if shooting digitally.

 

But in terms of how the ISO looks, that's a matter of testing and looking at the results on as large a screen that you plan on presenting in. And it would also help if you played with the image in color-correction to see how fast it falls apart.

 

Also, keep in mind that you don't necessarily have to increase all the light everywhere, you might decide just to boost it in one area and let the rest play a little underexpose.

 

It helps if you take a few photos at the f-stop and ISO you'd like to shoot at -- let's say that is f/2.0 at 800 ISO -- so you see what the space looks like even if it is underexposed. You may decide it looks fine darker and all you need is a little more light on the faces in one area, or just need to boost one source a little more but the rest are fine.  That's the job of previsualization when the cinematographer imagines what the space will look like as different lights are added, adjusted, or even turned off.


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#3 Duca Simon Luchini

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Posted 06 August 2016 - 03:20 AM

The cinematographer will measure the natural light levels on location during a scout knowing what the fastest stop of the lens they will be using and if they want to shoot wide-open.

Okay, but the problem is you are going to use many lenses... for example, in a scene indoor, you can use a wide lens for the Establishment shot (Master shot)   (i.e. 24mm or a 35mm) and than you use a 50mm, 85mm, 100mm or/and 135 mm for the Coverage. And every lens has a different f/ stop...

So, if I have rightly understand, you have to scout  you location referring your brightest lens you are going to shot (normally is a wide lens as a 24 or a 35mm). For example, I have a Canon 15-55 f/2,8, so I have to set up my meter to  f/ 2,8 as aperture and than provide to measure natural source lights trying to use a good compromise about ISO value?

 

 

But let's say you scout a location and it says you need to shoot at f/2.0 (if that's what you are limited to) at 3200 ISO and you plan on limiting yourself to 800 ISO.

I don't understand this step: if you want to measure the natural light levels on location you have to set up ISO value

 

You either have to add 2 more stops of light or get an f/1.4 lens and add one more stop of light, or compromise and shoot at f/2.0 at 1600 ISO. You may decide to cheat a little and open the shutter from 180 degrees to 240 or 270 degrees if shooting digitally.

 

But in terms of how the ISO looks, that's a matter of testing and looking at the results on as large a screen that you plan on presenting in. And it would also help if you played with the image in color-correction to see how fast it falls apart.

 

Also, keep in mind that you don't necessarily have to increase all the light everywhere, you might decide just to boost it in one area and let the rest play a little underexpose.

 

It helps if you take a few photos at the f-stop and ISO you'd like to shoot at -- let's say that is f/2.0 at 800 ISO -- so you see what the space looks like even if it is underexposed. You may decide it looks fine darker and all you need is a little more light on the faces in one area, or just need to boost one source a little more but the rest are fine.  That's the job of previsualization when the cinematographer imagines what the space will look like as different lights are added, adjusted, or even turned off.


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#4 Bill DiPietra

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Posted 06 August 2016 - 01:23 PM

Also, keep in mind that you don't necessarily have to increase all the light everywhere, you might decide just to boost it in one area and let the rest play a little underexpose.

 

That's exactly what I see in a lot of student films, these days.  Filmmakers feel that they need to light the entire space, often creating an uninteresting frame.  I know cameras have high-dynamic range today, but it's always refeshing to see someone who knows how to play with extreme over or underexposure, creating nice color-contrast.

 

So as David said, don't be afraid to experiment with different lighting styles.


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#5 Duca Simon Luchini

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Posted 10 August 2016 - 01:12 AM

Hallo guys,

yes this is what I look for when i try to create a lighting: isolate what is important. So, let's light what you need...

So ,  think you should find

 

 

The cinematographer will measure the natural light levels on location during a scout knowing what the fastest stop of the lens they will be using and if they want to shoot wide-open.

 

Okay, but the problem is you are going to use many lenses... for example, in a scene indoor, you can use a wide lens for the Establishment shot (Master shot)   (i.e. 24mm or a 35mm) and than you use a 50mm, 85mm, 100mm or/and 135 mm for the Coverage. And every lens has a different f/ stop...

 

So, if I have rightly understand, you have to scout  you location referring your brightest lens you are going to shot (normally is a wide lens as a 24 or a 35mm). For example, I have a Canon 15-55 f/2,8, so I have to set up my meter to  f/ 2,8 as aperture and than provide to measure natural source lights trying to use a good compromise about ISO value?

 

 

But let's say you scout a location and it says you need to shoot at f/2.0 (if that's what you are limited to) at 3200 ISO and you plan on limiting yourself to 800 ISO.

I don't understand this step: if you want to measure the natural light levels on location you have to set up ISO value

 

You either have to add 2 more stops of light or get an f/1.4 lens and add one more stop of light, or compromise and shoot at f/2.0 at 1600 ISO. You may decide to cheat a little and open the shutter from 180 degrees to 240 or 270 degrees if shooting digitally.

 

But in terms of how the ISO looks, that's a matter of testing and looking at the results on as large a screen that you plan on presenting in. And it would also help if you played with the image in color-correction to see how fast it falls apart.

 

Also, keep in mind that you don't necessarily have to increase all the light everywhere, you might decide just to boost it in one area and let the rest play a little underexpose.

 

It helps if you take a few photos at the f-stop and ISO you'd like to shoot at -- let's say that is f/2.0 at 800 ISO -- so you see what the space looks like even if it is underexposed. You may decide it looks fine darker and all you need is a little more light on the faces in one area, or just need to boost one source a little more but the rest are fine.  That's the job of previsualization when the cinematographer imagines what the space will look like as different lights are added, adjusted, or even turned off.

 

 

I David, I forgot  I forgot to highlight  text with my considerations... I make it here above:


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#6 Duca Simon Luchini

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Posted 11 August 2016 - 02:22 AM

I don't know why I can not edit my message... :angry:

 

Anyway, I try to write again what I wanted to say:

 

As I said, the first approach should be to isolate (light) what is important for you (for the script, for the scene, for the Director...), regardless of how it illuminated the scene originally. Okay.

 

But there are many cases (Docs, Historical, Turistic, ...) where you have to consider to PRESERVE the original on location lighting:

For example, if we are in a Church, or a Villa, or a Gallery or historical place or in every place who the lighting location has something special (authentic, original...)  - we can meter the original lighting contrast ratio and preserve itif we need to increase the brightness of the scene because we have little light lenses, for example.

Vice versa,  another interesting aspect to check the original on location lighting - when it is too bright [as a DAY Outdoor scene, or DAY indoor scene with many windows or on site lighting sources (Offices, supermarket, ...)] - is to underexpose the scene to see better the contrast ratio of the original scene, evaluating if it could be great for your creative/narrative purposes.

 

Of course, when you shot an underexposed scene, you should use ND filters to preserve the possibility to choose the Aperture only for Depth of field (Soft or Deep focus).


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#7 Robin R Probyn

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Posted 11 August 2016 - 07:02 AM

Of course, when you shot an underexposed scene, you should use ND filters to preserve the possibility to choose the Aperture only for Depth of field (Soft or Deep focus).

 

 

Do you mean over exposed..?..  


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#8 Duca Simon Luchini

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Posted 11 August 2016 - 07:24 AM

Of course, when you shot an underexposed scene, you should use ND filters to preserve the possibility to choose the Aperture only for Depth of field (Soft or Deep focus).

 

 

Do you mean over exposed..?..  

Of course, over exposed! 

 

(But the REAL problem here is I can not edit my messages... :unsure:)


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#9 Robin R Probyn

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Posted 11 August 2016 - 09:12 AM

ah right.. yes there seems to be some sort of time limit to edit.. as far as I can see.. 


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