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Suggestions or Good Reference Material for Spot Metering Techniques for Film?


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#1 Karl Lee

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Posted 11 May 2014 - 01:43 PM

Can anyone recommend any resources, either online or in a book, which serve as a good refresher / tutorial for light metering for cinematography (I'll be shooting S16 film), particularly spot metering? 

 

I'm planning on shooting some test footage with my new S16 camera in the near future, but it's been a while since I've read up on the finer points of spot metering.  I have a Sekonic L-508 combined incident & spot meter which I've used a fair amount for incident metering, but haven't used the spot functionality too much.  My plan for the test shots is to include landscapes and city skylines, neither of which lend themselves to incident metering. 

 

I certainly understand the main concepts of spot metering, but in real life it's not always possible to get a spot reading on distant objects that are equivalent to 18% gray, so I need to learn how to work around that and work with what's available.  Plus, let's say I want to film a skyline and some buildings are in direct sunlight while others are in shadows, or a landscape which is partially in direct sun and partially in shadows.  In this situation, I'd need to learn the best methods for determining optimal exposure based on multiple spot readings in the scene and all of the possible variables that could be in play. 

 

I realize that ultimately, good metering technique is best learned by trial and error and real-life practice and experience, but nonetheless I'd like to prepare and learn as much as possible beforehand.  Fortunately, color negative film tends to be pretty forgiving and has pretty good exposure latitude, but I still want my ultimate decisions for exposure to be as accurate as possible.  That said, any personal suggestions or suggestions of particular reference material online would really be appreciated.

 

Thanks! 


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#2 Stuart Brereton

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Posted 11 May 2014 - 02:07 PM

Research Ansel Adam's Zone System. It's a very clear and concise approach to reflective metering. Be aware that it was originally developed as part of a system which also included various processing and printing techniques as well.


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#3 Adrian Sierkowski

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Posted 11 May 2014 - 03:05 PM

Yep,Zone system.

 

though for myself, what I'll often to is just treat everything like it was middle grey to get an idea of stops over and under. I wouldn't base exposure off of a spot metering, but rather rendering. I'd incident for a rough exposure, then if I spot a lamp shade, for example, and it's reading 5 stops over my incident-- or whatever I have spotted and chosen in the scene to represent my middle grey, then I know I'd have to deal with it somehow.

 

If all else fails, find a person and meter them, they'd either be 1 over or 1 under middle grey as a baseline roughly.


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#4 John E Clark

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Posted 11 May 2014 - 03:46 PM

Can anyone recommend any resources, either online or in a book, which serve as a good refresher / tutorial for light metering for cinematography (I'll be shooting S16 film), particularly spot metering?

 

For me, when using Film film, there are several considerations. However, I've only shot still Film film, so perhaps some of the 'what will I do with this shot in film negative development and printing', may not be available to the Movie Film user.

 

However, there are a couple of 'fixed points'... while one does not have a grey card often available, I will take a meter reading off the forhead of the subject... if human... and if the person is fair skin adjust by open up 1 stop from the meter. 'mediterranean' complex, leave as is, and dark complexion, closing down 1 stop.

 

For non-human subjects, green folage in shadow, often evaluates to 'middle grey', where as green folage in sun may again be 1 stop brighter.

 

White buildings are perhaps +1.5-2 stops brighter than middle grey, 'grey' buildings +1 stop... etc.

 

One can on a reasonbly 'sunny' day take a meter reading from a local 'grey' card, and assume that the light falling on the distant subjects is 'the same', and expose accordingly... for cloudy, or partially cloudy days... that doesn't work so well...

 

 

 

For still film there was the 'convention' of exposing for the shadows, and developing for the highlights. With that in mind, one may 'place' shadows at 2 stops under the spotmeter reading, read what the 'high values' are, and adjust by 1-2 stops the development time to prevent the highlight values from becoming too dense.

 

I don't know with modern movie Film film, whether this is an appropriate convention. Perhaps with digital scanning of the original negative, curves can be used to 'adjust' the values to match the desired output device.


Edited by jeclark2006, 11 May 2014 - 03:47 PM.

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#5 Stuart Allman

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Posted 11 May 2014 - 05:24 PM

Karl,

 

Art Adams had an interesting article over at provideocoalition.com that you may find helpful.

 

http://www.provideoc...e-system-for-hd

 

Stuart

--------------------------

illuma.blogspot.com


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#6 Jon Rosenbloom

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Posted 31 May 2014 - 08:26 PM

If you can still shoot reversal stills, that's a great way to get a feel for spot metering. The idea to get used to is that the spot meter tells you what f-stop will render whatever you're pointing at as middle grey. It's simple enough, but does take a bit of practice before it becomes automatic.

 

Before my meters began their long slumbers in the back of the dresser, I would check them against each other by taking an ambient reading at arm's length, then holding my hand in the same place and spot reading it. If the spot reading was a stop higher than the ambient, I was good to go.


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#7 Jon Rosenbloom

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Posted 31 May 2014 - 08:46 PM

For some reason, I'm not permitted to edit my post, so:

 

It's kind of a waste to worry over whether you can find a middle grey part of a frame; an ambient meter gives you the same reading you would get if you spot read a grey card. You dig? A spot meter can help you analyze the scene in front of you. But, if you have a complex scene with deep shadows, bright skyline, and so on, the critical thing is that you have to decide what's most important to you in that scene.


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#8 Stuart Brereton

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Posted 31 May 2014 - 10:21 PM

 the critical thing is that you have to decide what's most important to you in that scene.

Exactly. That's what the Zone system and previsualization is all about. Not what is middle gray, but what do you want to be middle gray.


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#9 Dirk DeJonghe

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Posted 01 June 2014 - 12:51 AM

Ansel Adams 'The Negative' is invaluable for serious understanding of how film works.

Of course you will work with fixed development gammas in MP color, but in B&W you can process to lower/higher gammas.

 

Use his empirical film testing procedure in Appendix A to test the sensitivity of your camera/lens/exposuremeter/stock/processing combination. This will tell you the -4 stops reference point (black with detail). After a keylight test (using the sensitivity you just found) you will know the falloff point of your highlights.

After that, practice, practice, practice, did I say practice?

 

His advice is: "expose for the shadows, let the highlights fall".


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#10 Stuart Brereton

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Posted 02 June 2014 - 10:47 AM

His advice is: "expose for the shadows, let the highlights fall".

This is good advice, with one important proviso. Adams did expose for the shadows, but controlled his highlights through Push/Pull processing. This was possible and practical because he was shooting single frames in Large format. One of the reasons he resisted shooting roll film was that he was unable to process each frame individually.

 

Although Push/Pull processing is possible with motion picture film, it's not a practical way of controlling highlights as whatever changes you make to the processing time affect the entire roll.


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#11 John E Clark

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Posted 02 June 2014 - 11:23 AM

This is good advice, with one important proviso. Adams did expose for the shadows, but controlled his highlights through Push/Pull processing. This was possible and practical because he was shooting single frames in Large format. One of the reasons he resisted shooting roll film was that he was unable to process each frame individually.

 

Although Push/Pull processing is possible with motion picture film, it's not a practical way of controlling highlights as whatever changes you make to the processing time affect the entire roll.

 

Ansel Adams did use, and apply his 'zone system' to Polaroid materials, and while one could 'adjust' the developing time, it definitely was more of a 'test to find the limits' approach.

 

Not unlike what one needs to do with any digital camera, especially DSLRs. When I first began using DSLRs for stills, late 1990's, it occurred to me and others in some sort of group epiphany, that digital cameras behaved more like 'slide film' than 'negative film'.

 

I'm pretty much convinced that for the most part DSLRs have maintained that 'goal' of 'ready to view' imagery that slide film was intended.

 

In that sense then, the method that Adams used to evaluate and calibrate to Polaroid materials is probably more in keeping with what one would do to determine one's own operating procedures for digital imaging, at least in the DSLR category.

 

In the higher end cameras, there is perhaps useful 'dynamic range/latitiude' in the higher 'densities', but it is still more of a method of discovering limits, that yield the best images.

 

I will also note that Ansel Adams was predominantly a 'Black & White' photographer, and never really did make 'color' a significant part of his work, even though later in his life he did work with color materials...

 

I've often mused that most people who shoot DLSRs would do better to shoot for converting to monochrome rather than worry about the myriad of problems with 'color', either camera's 'color science' or the lights and their spectrum...


Edited by jeclark2006, 02 June 2014 - 11:24 AM.

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#12 Dirk DeJonghe

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Posted 02 June 2014 - 02:48 PM

Stuart,

 

If you read my post again, that is exactly what I am saying.


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#13 Stuart Brereton

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Posted 02 June 2014 - 06:00 PM

With respect, Dirk, your post is not completely clear, particularly if one doesn't have a copy of 'The Negative' to refer to.

 

In any case, I think that it is always worth pointing out to students and beginners that Adam's Zone System for exposure was just one part of his system, and although it is very useful with motion picture work, it shouldn't be applied without an understanding of what it was originally designed for.


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#14 John E Clark

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Posted 02 June 2014 - 06:34 PM

With respect, Dirk, your post is not completely clear, particularly if one doesn't have a copy of 'The Negative' to refer to.

 

In any case, I think that it is always worth pointing out to students and beginners that Adam's Zone System for exposure was just one part of his system, and although it is very useful with motion picture work, it shouldn't be applied without an understanding of what it was originally designed for.

 

Yes, looking at the Negative was only 1/2 of the process... the other 1/2 was looking at the print materials, and finding their characteristics.

 

While most of my cohorts would take densitometer readings from the negatives, most, myself included, would not get density reading from paper, but would determine the 'dynamic range' as it would be called today, of the paper, usually about 7 to 8 stops from 'black' to 'white' for a 'normal contrast' paper, by a more ad hoc method... exposing the sheet of paper to varying amounts of light...

 

The whole process was directed to 'seeing' the final print, given the real scene at the time of shooting.

 

What was important was knowning the 'negative' and what could be done with it, and corresponding, what was the final output, and what could be done with it.

 

These days, the final output for most people I am going to hazard is some form of computer display via some sort of internet service (web page, streaming, etc.). Few people will actually see their works on a Real Live Motion Picture Screen. Sure some few may, but even for many 'fests' the lesser lights get either a crappy projector on a 'big screen' or get shunted off to a 'auxlliary room' and has a 'tv' of dubious quality and calibration.


Edited by jeclark2006, 02 June 2014 - 06:35 PM.

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