Using The Damn Light Meter

>Also, some (generally the cheaper industrial series) monitors will have >a self terminator built-in. This is almost always a source of problems

This includes the ubiquitous Sony 8044s and 8045s.

One of my 8044s has flaky auto termination on one input...(Intermittent, of course.) Through earlier CML conversations, I understand that it's not at all unusual for that model of monitor. (Mine now has a terminator there full-time.) This hasn't been a major problem for me, because I've noticed a suspicious difference between the zebras/viewfinder and what seems to be going on with the monitor long before tape is rolling.

I suspect the odds of something going wrong in this chain increase dramatically the more people are involved... If you're always operating yourself, and you're in the habit of checking with zebras frequently (which is pretty much my life), then you catch the inconsistency right away.

If someone else is operating, and doesn't speak up, it can slip through more easily.

George Hupka
Director/DP
Downstream Pictures
Saskatoon, Canada

Talking about lighting is like talking about religion. In my religion, light exists as a 3 dimensional volume. It falls off at a square of the distance and interacts with surfaces to generate secondary and tertiary volumes as well. A meter tells me quantitatively what my lighting ratios are in a three space, a waveform tells me the 2D results and a monitor gives me a visual reference that can be used to judge the picture qualitatively. Nothing gets replaced, nothing is better or worse than. Different tools do different things.

Cinematography is a craft, and every bit of gizmology that negates understanding, contributes a vanilla-fying effect to the cinematic future of HD.

Scott Billups - Hollywood

>Talking about lighting is like talking about religion.

You've been talking to physicists lately?

>A meter tells me quantitatively what my lighting ratios are in a three >space

You mean, if you walk around the scene and take measurements, right? 'Cause, if you measure from the camera's POV, you are certainly not doing anything that the camera couldn't do.

(I did warn that I was going to be somewhat dense about this)

I'm not challenging anything you are saying here. I understand that there isn't one perfect tool and that each will use whatever he/she is used to or more comfortable with. I'm just trying to understand for my own edification.

Now, let's talk about what degree of control you have at the camera :

- Sensor (by choosing camera)
- Lens
- Frame rate
- Shutter speed
- Aperture

Without the processing of a video camera (Viper) the rest is pretty much smoke and mirrors.

The sensitivity of the system is absolutely defined by your sensor choice (the camera). No amount of voodoo will get you more or less sensitivity. So, for all intents and purposes, this is fixed.

The lens. Known and fixed quantity. You slap a DigiPrime on that baby and that's what you have. No adjustments.

Frame rate. Some choices. Let's nail it at 24fps.

The shutter speed might, by necessity, be constrained to within a very narrow range due to motion considerations, for example.

That means that the aperture might be your only real variable.

If all of the above is true, you would then see to use your light meter (or the camera) to light the scene in order to work within the achievable capture range. Say, 5 to 7 stops?

Without a camera on set you can start your work with a light meter and setup as complex a lighting arrangement as necessary. I interpret what you are saying about light meters to mean that this is the tool that travels the set with you while you decide how to use your paintbrush (light). And, that this is the tool that lets you explore what you are painting in a more intimate way. Understood. A camera/scope can't do that, unless we make a very small one and make it portable. But, what would be the point?

With the scene set, and if you've used the light meter to paint per your vision, you can then use the camera/scope/monitor to ensure that the all the data you'll need in post is captured. This, per my discussion above, sort of boils down to setting the aperture (or using filters to work at the desired aperture range). The artistic impact of the images was, however,
created with paint made out of light with the light meter as the tool of choice.

Did I get it right?

Martin Euredjian
eCinema Systems, Inc.

Re EI ("ASA") I was specifically curious what Blain would have done *in this case*

>Monitors can show you the 2D results of your 3D volumetric choices but >they don't replace the lightmeter. Technology does not replace >methodology.

I know what you're saying here, and understand it as working method.

But doesn't the final print or TV image show you the 2D results of your 3D volumetric choices ?

Sam Wells

>250-320 seems in the range for the F900 at 1/36th shutter. I would >never make critical exposure calculations using a meter set that way but >it's good for roughing things in and then fine tuning with a big monitor

I would recommend 400 ASA at 1/48th Shutter.

1/36th is 1/2 stop faster than 1/48th
250 ASA would place the exposure
Over exposed by over 1 stop.

So if you like to shoot HD as if it was negative film then this is the way to really overcook your exposures.

Again For a solid exposure (Slightly under) set Meters to 400 ASA and 1/48th Sec

To exactly Nail the exposure (insuring a few things are properly set in Camera) Go 320 ASA at 1/48th.

I teach this at the Santa Fe Workshops and make sure everyone knows the ramifications of everything you adjust in camera. USC 22-26th May.

Just because you own a meter doesn't mean that you know how to use it any more than having a WFM will be a guaranty of success if you don't know how to read it.

B. Sean Fairburn SOC
Director of Photography
Castaic Ca

Important point Blain.

A couple of follow ups :

When I worked as a TV camera operator, late 70's, we had to set up our shot boxes, for those who don't know what a shot box is it's a device for TV studio cameras that remembers zoom lens positions and can easily access them via big buttons, anyway we had to park our peds on a fixed point and line our shot boxes up with fixed lens sizes and the from then on work o0ff the shot box and not the zoom. If a lens size wasn't quite right we had to move the camera, this is one of the reasons that I still prefer primes to zooms, they make you think about where the camera is.

On waveforms, there are some very cute small ones that will superimpose a w/f over the picture on a monitor. I've got a very old prototype of one that does this but with multiple inputs and via a wavy line going straight lets you phase sources as well.

> I would recommend 400 ASA at 1/48th Shutter.

This is certainly my experience as well and the rating that was used for the F900/Viper tests.

I work on the basis that for reversal you need to play safe with the highlights.

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based
www.cinematography.net

>I would recommend 400 ASA at 1/48th Shutter.

Actually I wasn't specific enough; ASA ratings for 24p cameras are almost always calculated at 180 degree shutter which is 1/48th, so 320
is an accurate number for the Viper at a 180 degree shutter.

GEORGE C. PALMER
HDPIX, INC.

>The artistic impact of the images was, however, created with paint >made out of light with the light meter as the tool of choice.

>Did I get it right?

Close enough.

The quality of light is best described by the shadows it casts. By using light to define regions within the compositional framing of a shot we can create an enchanted perception of depth and dimension. Not much of this other than bulk value, translates into a WFM.

Rarely do actors stay in one position unless you're shooting a sitcom type show with a coop the size of a school bus hanging from the grid above you. When you set the lights for dramatic movement you might have a shot where you want to gradually increase the value of the volume so that the actor or actors have room to move. You can walk the scene with your meter in seconds and make tweaks or give direction to the gaffs while on the move. Guiding a stand-in through the marks might take the better part of an hour to tweak using a WFM and monitor. The eye is an imperfect instrument, it adapts far too easily and even the most trained eye might not be able to match positions that are ten or twenty seconds apart. With a meter, you know that the F 5.6 over by the door is the same F 5.6 that is by the window.

Different types of volumes will give you different emotional correlates. You might build a soft, inverted horseshoe for an aging leading lady to walk into for a close-up. Some actors look better in high, flat ambiance while others look better in Hurrellian contrasts as easily witnessed on the walls of Panavision. With a dependable meter and a decent kit you can paint the spectrum of emotion into a scene before the players hit their marks. A thousand different lighting combinations can all look the same on a WFM.

Scott Billups - Hollywood

Martin Euredjian wrote :

>I'll tell you what this issue boils down to:
>[a] Electronic acquisition with processing in post (as with film) or [b] >Electronic acquisition with as much of the image crafted on-set/location

I agree with Martin but I'd like to reduce it even further. This is actually a discussion about the post production budget and about control.

Why wouldn't you allow all painting to be done in post if you were certain that it would actually get done to your specifications? If you want the creative energy of the set to inspire you, record sample frames: tweak away but when you roll record the full image. Recreate it later, perhaps better.

There are certain types of filtration that cannot accurately be recreated in post. Those must be done on set. However, do cinematographers own Tobacco filters because that color could not possibly be recreated in post?

My experience is that on most projects below a certain budget the vision from production might not make it to post but the recorded image does. If you want to create the aesthetic on these projects, you are forced to do your grading on set.

This is not a discussion about which method is better. It is really about which one is affordable.

Jim Iacona
DP
San Francisco

This is not a discussion about which method is better. It is really about

> which one is affordable.

And Often that decision to shoot HD was made because the production wanted to Save money. That decision permeates every other decision they make as well.

B. Sean Fairburn SOC
Director of Photography
Castaic Ca

I don't know what was going on yesterday. Out here in the rest of the world we get the list as a whole so if America were speaking to itself all day long what we get to see is a long stream of consciousness. Some of that stream was - well, needing of correction.

In my opinion :

Light meters measure light in a particular kind of way.

Waveform Monitors and Vectorscopes measure and display signal at the end of a chain.

Cameras and recording formats (including all of film technology) collect light in particular ways for display on:

Monitors, crt and flat screen, projectors and various other display modes (if YOU or your engineer has your finger up your arse on this then you're screwed - just set the crt up right then electrocute anyone that tries to touch a control)

Eyes collect... No, eyes don't collect or measure anything, they're connected to the mind which between eye and brain develop intuitive responses to light...

All the rest of the stuff is just crutches to walk with and yes guys - its all relative...

I guess a suitable analogy is that of light telescopes and infra red telescopes, and gamma ray telescopes... You really have to know the nature of the output you're looking at.

In January I shot a feature in 13 days - 13 DAYS !!!!@!!! - we were in a country house with heavy brown wood panelling and faces from bright white to blue black nubian - what to do to make it work when sometimes the going was so fast that a monitor wasn't an option....backlight or negative rim - at least you saw a silhouette...and I hate backlight. The feature's cut and in Cannes right now - cut and graded on Final cut - never done it before but it looks great.

From my point of view if I want to get the exposure right on HD then I light, look, maybe get a meter out occasionally, look through the viewfinder, look at the monitor, go stand behind the camera, scratch my head, scratch my arse, joke with the gaffer, have a coffee, look again - and then drop the exposure by between one half and one full stop every time.

Has anyone ever been distracted enough by exposure to have put an entire cup of coffee in their coat pocket ? And then find it a little later ? Yep - I got that stupid and that involved!

  Terry ...style="font-size: 11px">(what is this stuff in between given names - I guess I might write a poem or maybe input the contents of a telephone directory or maybe all of Anna Karenina - or maybe not - oh and whilst were at there's absolutely no point in disputing the definitions above because I made them up and I'm sure there's another way of writing them all again) ... Flaxton

UK DP

Sean exclaims :

>"and Just because you own a meter doesn't mean that you know how to >use it..."

I've been reading this pissing match between the meter heads and the waveform heads and it's starting to sound like the film vs. tape debate that encompassed early sessions of this list.

In the early days of studio TV, the lighting director/engineer would set the lights so you had roughly 250 foot candles across the board.

Bright, cheery, sharp and mostly flat, flat, flat!

I cannot tell you how many engineers I've butted heads with when I moved from film to tape. It was difficult to get an engineer to understand that what he was calling "spiking", I was calling shadow or modelling.

When lighting for film it's more about the ratio of light rather that the amount and that holds true with tape as well.

It's really the quality rather than the quantity and to that end, a light meter is very useful in determining the lighting or contrast ratios you are creating.

Now with that being said, a good monitor and even a waveform (to keep you honest), is yet another tool to bring to the table.

However in my opinion, a good light meter along with a well set up camera zebra system can and in my case, does replace the waveform.

A good monitor just adds icing to the cake, although I bring two monitors to bigger studio sets, a good TV and a good monitor.

I want to see what the image is going look like on a TV because that's where it's going to end up and the monitor is used for critical detail, i.e. focus, color, etc.

Regards,

Allen S. Facemire
DP/Director
SaltRun Productions,inc.
Atlanta

>this pissing match between the meter heads and the waveform heads

I think you misinterpreted the tone and intent of the thread. This was no "pissing match" at all, it was a mini class on the need and importance of a light meter taught primarily by Scott Billups.

Went to school. Got it. Moved on.

BTW, Scott, I think your next book needs a chapter on this subject and how/why some of the old ways are still very important.

Not directly related to light meters, but...Something that hasn't been mentioned here is Accuscene's approach to intuitively reading IRE levels right on the viewfinder. I haven't seen it yet, but I heard it is an interesting approach.

Maybe someone more familiar with it can bring the list up to speed on this.

Martin Euredjian
eCinema Systems, Inc.

Martin Euredjian wrote:

>it was a mini class on the need and importance of a light meter taught >primarily by Scott Billups.

I have light meters, and I use them on HD shoots. I use a wave form monitor and a vector scope as well. I use them for different things. I use the right tool for the job. But the job itself is what is changing. The worlds of film and HD are in collision, and the faster we drive at each other, the more the collision hurts. I come from a film and vfx background, and if I can learn to use new tools, techniques and skills, anyone can.

If everyone will just stop trying to prove their point and start embracing change, we can then guide the manufacturing community to build tools that will work for all of us in the future. The companies that build this stuff have the greatest part to play in melding the worlds of HD and film, and if they do not take the task to heart, the schism between the two worlds will remain.

If we are bent on reinventing the future, we ought to remember to try and make it better along the way.

Dave Stump ASC
DP/VFX Supervisor
Los Angeles, California

Martin Euredjian writes:

>I think you misinterpreted the tone and intent of the thread. This was no >"pissing match" at all, it was a mini class on the need and importance >of a light meter taught primarily by Scott Billups.

I think the waveform monitor is more analogous to a densitometer, than to a light meter. A light meter is an indispensable tool; however no matter how skilfully it is used in creating beautiful and consistent lighting, unless that is translated to proper "exposure" of the film or the tape, the results can be problematic.

A DP working without feedback from a lab on correct density can be doing him or herself a great disservice, likewise when "exposing" tape without benefit of the immediate feedback provided by a WFM.

BTW, many extremely well lit and photographed films were made before the development of the light meter. In those days, the DP generally spent a lot more time in the lab seeing the results directly.

Brian Heller
IA 600 DP

David Stump wrote :

>The companies that build this stuff have the greatest part to play in >melding the worlds of HD and film, and if they do not take the task to >heart, the schism between the two worlds will remain. If we are bent on >reinventing the future, we ought to remember to try and make it better >along the way.

Nicely put, Dave.

We're doing our best... to me, the important thing is not to ignore 100 years of cine equipment evolution -- there's much to be learned from it.

Jeff "like the hand-crank, for example" Kreines
www.kinetta.com

>I think the waveform monitor is more analogous to a densitometer, than >to a light meter.

The camera/monitor/wfm can only see things within its field of view. You can't pre-light a set with them before the camera truck has arrived. OTOH, I find a digital still camera (on manual exposure) particularly useful for explaining lighting decisions to others, for film or tape. Portable, easy to scroll through previous shots, the EXIF metadata stores exposure info, and it has a histogram.

Tim Sassoon
Santa Monica

>In those days, the DP generally spent a lot more time in the lab seeing >the results directly.

I like to call that "Testing"

Before ,,, during,,, and After.

That was his version of a Monitor (but a bit slower)

It is also closing the Loop of understanding the causal relationship (Cause and effect)
of our actions.

In the military its called the "OODA-Loop"

Observe
Orient
Decide
Act
Then do it again but quicker-Loop

We are consistently doing this in our work and How fast we do it is based on the accuracy and consistency of the information we get when we use all the tools at hand or just one of
the tools to Observe what the hell is going on out there with the light and how that affects the images as they are harvested by the Camera.

Bad Images come from bad Actions
Bad Actions come from bad Decisions
Bad Decisions come from bad Orientation
Bad Orientation comes from bad Observation.

Bad observation comes from inexperience and not knowing how to use available tools designed to help you. "That boys OODA-Loop is all messed up" even though somehow some of us manage to Forrest Gump our way through the difficult shots (I for one) while the Obvious is playing Hide and Seek in another yard somewhere. (and being seen and suggested by the PA)

OK we had better change the title here so future CML’ers don't go crazy.

So if someone ever comes up to you and asks How's your OODA-Loop don't point him to the craft service table. Just say "Tight" which means That I am quickly making critical value judgements based on all the experience I have and feel confident in the repeated decisions and actions I am taking based on that real time information.

B. Sean Fairburn SOC
Director of Photography
Castaic Ca

Scott Billups wrote :

>You can walk the scene with your meter in seconds and make tweaks >or give direction to the gaffs while on the move.

I assume that you are talking about using an incident meter. The camera and the waveform monitor are effectively spot meters. When your actors are moving it is very difficult to set proper exposure for the entire path using only a spot meter. Walking the set with an incident meter gives you information that is unavailable from a waveform monitor or monitor - especially when you are shooting air until an actor steps in.

I generally favor the waveform monitor over a spot meter on a video shoot. However metering a blue screen is much faster with a spot meter. You see exactly where the problems are.

Jim Iacona
DP
San Francisco

>Maybe someone more familiar with it can bring the list up to speed on >this.

I had a look at it at NAB, and spent some time chatting at the booth.

Essentially, it uses the colour viewfinder in a totally new way - producing a "false colour" image, if you will, using different colours to represent different exposure values.

At the booth it struck me that it would be exceptionally hard to operate this way, but I was told that after a couple of hours, you can become quite proficient... And in certain circumstances it can also function as a focussing aid (since the gradations of exposure can be set to show up as quite sharply defined lines - saw this myself at the booth.). I believe there's also a fair bit of room to customize to your preferences.

This will be one of those features that some people love and some people hate... But I certainly wouldn't object to having a "digital zone system" available at the push of a button to check exposure!

It would be interesting to hear from someone who's used this feature in the field!

George Hupka
Director/DP
Downstream Pictures
Saskatoon, Canada

Blain writes:

>One of the scenes looked so good that I called the gaffer over and told >him "This is the best lighting we've done yet on this show. It looks >terrific." I'm now editing that scene. A probable reshoot. Terribly >underexposed.

I absolutely can't fathom why every professional B&W video finder doesn't incorporate a waveform monitor.

Wade Ramsey writes:

>I point out that a monitor does you no good when you are "lighting air".

A gray card or ball (plus a monitor and a WFM -- or zebras and the Zone System in a pinch) will actually do very nicely in lieu of an incident meter.

Dan Drasin
Producer/DP
Marin County, CA

By my experience shooting with F-900 at 24 psf 1/48, sensibility is between 250 and 400Asa. With film gamma of CVPfile editor I use 250Asa and for example with Initial 5.0 I use 400 Asa. When you transfer to 35mm you can see the density of grey chart and compare with negatives film in order to see the sensibility of camera with differences menus. It is important to use light meter for pre-lighting and control contrast relations, but finally

I use waveform monitor and monitor too.

Alfonso Parra (a.e.c.)
www.alfonsoparra.com

Dan Drasin writes :

>I absolutely can't fathom why every professional B&W video finder >doesn't incorporate a waveform monitor.

Wouldn't that make the viewfinder rather large -- and heavy?

Brian "Remembers flak Arri took about built in light meters" Heller

This meter..... that meter......

They are all just tools, and you should use the right tool for the job. But instead of "or", in many cases it could be "and".

Almost all D/P's I know light with a light meter. Incident and spot...or incident or spot. It is a tool to balance the light based on the look and the creative decisions. It is a tool that allows a quantitative value be placed on light, so that communication with the rest of the crew is clear and concise. It is a tool to check the spread and intensity of light, and enables an experienced DP to know without a doubt how the scene will look on the recorded medium.

If the recorded medium is film, then the light meter enables lighting to be set to the sensitivity of the chosen stock.

If the recorded medium is digital data from electronic captures devices, then the meter is just as useful. BUT..... there is another tool which is helpful, and that is the waveform. This is a tool that can WITH a light meter, and not necessarily instead. If film still has the greater latitude, then setting the final exposure with a reference to the waveform allows the greatest latitude to be captured electronically. One of the posts on this subject stated <and then drop the exposure by between one half and one full stop every time.> Using the waveform enables the stop to be dropped just far enough to hold the peak whites that the DP wants to keep detail in, yet prevents the stop from being dropped arbitrarily below where it needs to be and enables the greatest detail in the bottom end to be preserved.

Price Pethel, one of the most talented men I know in the business, once drew a great analogy by comparing different ways of setting up and exposing a digital camera (factory settings vs. custom settings) to the difference between shooting on reversal stock or on negative stock. While not totally germane to this issue, there is some relevance nonetheless.

>
Who wouldn't choose the latitude of the negative? Why not check the signal with a waveform?

There is so much that can be done in the DI process, that it is a shame to walk into post with compromised footage when a glance at a waveform could have prevented these problems. At the same time, I couldn't imagine lighting a set without a light meter.

My two cents worth,

Steve Schklair
Cobalt Entertainment

>
>Was the on set monitor terminated?
>Excellent question. I don't know. A similar situation makes me think this >is quite important and I would like to hear more input on it.

Ah the termination....

Mr. Comnetz & I both free lanced for a company in NYC back in the day, that had a location truck that with a bad( wrong resistance) terminator on the Critical monitor. Being at the end of the signal chain you know what that means.

I had the feeling something was wrong with the situation but it took me a while to put my finger on it. After a couple of shoots where the pictures on the monitor did not match with what I saw in the VF of the camera, I got out a meter and checked resistance of terminators till I found the culprit and suddenly everything fell into place.

Lighting to a poorly set up monitor, or incorrectly terminated one is fools gold. I heard a story about a Varicam feature last year where the original Dp was replaced and the new guy, shooting with a 9" as his only monitor shot a campfire scene with African American actors which was about 3 stops under, no doubt due to lighting to a poorly set up monitor.

Mark Smith

>
>I point out that a monitor does you no good when you are "lighting air". A >gray card or ball (plus a monitor and a WFM -- or zebras and the Zone >System in a pinch) will actually do very nicely in lieu of an incident >meter.

Does anybody else on this list use their fist as a stand in when lighting air? (Grey ball...)

Personally I think this discussion is about personal preferences, personal methodology on how to translate a 3-dimensional world onto a 2 dimensional plane (our job/art). How do you achieve that in the end? Not through image acquisition methods but through lighting.

My 2 cents

Florian Stadler, D.P., L.A.
www.florianstadler.com

>
>A gray card or ball (plus a monitor and a WFM -- or zebras and the Zone >System in a pinch) will actually do very nicely in lieu of an incident >meter.

I have been using different kinds of balls on set on Vfx shots for ages, and I have developed their use to a fine art. A gray ball will give you an indication of 18 percent reflectance from your lighting. I find a somewhat shiny white ball is much more useful in HD where you are concerned about highlights and clipping. In Vfx work I most often use a chrome ball to reverse engineer the on set lighting for the 3D folks.

The highlights in a chrome ball photographed at the spot where a 3D cgi object is to be placed can easily be replicated in position, intensity, size, and color when a 3D chrome ball is generated and used to replace the real chrome ball. Using reflectance vectors, one can then place cgi lights and reflectance maps so as to correctly light the 3D object to match the onset lighting. Combined with High Dynamic Range Imaging some very convincing cgi lighting can be achieved. For Stuart Little 1 I had a small "minora" (someone please check my spelling) of a silver ball, a gray ball, and an off white Stuart fur coloured ball so the 3D department could have a Stuart Little lighting guide built into every shot in the movie.

On the show I am currently supervising - INTO THE BLUE - for MGM, I got several sizes of chrome balls from 6 inch to almost two feet in diameter, drilled them out to sink quickly, placed handles on them, and had divers swim them through shots where I intend to place cgi sharks. There is some very amusing footage of "Johnny Props" swimming alongside our boat at his best shark pace, with the large chrome ball hoisted just above water level.

On Red Riding Hood I used a very large white ball courtesy of Camera Operator Joe DiGennarro, which I only recently returned to him. The white ball was used before every shot, trotted through the actor's path, to determine if there were any offending hot spots that would excessively or unartfully peak the WFM.

Dave Stump ASC
VFX Supervisor?DP
LA Calif. 5/2004

>
David Stump writes:

>I had a small "minora" (someone please check my spelling)

I don't think there's a thoroughly standardized Hebrew - English transliteration, but the usual spelling is "Menorah."

Dan Drasin
Producer/DP
Marin County, CA

>
I got to his discussion a little late, but it seems to me that one vital use of the light meter has been omitted.

If you need to aim for a certain f-stop because of lens choice, filter choice, depth of field or because you have an uncontrollable light source in the frame that you need to match, I doubt whether a vectorscope is going to be of any use other than to check the final result.

I would imagine it to be very cumbersome to put a camera on a set with the desired f-stop and then lighting until you see a picture that matches the waveform!

My opinion is that in HD both tools are indispensable, but have different uses.

Roger Simonsz
DP/Operator
Paris

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