HD Exposure

Anyone have a quick way to find an exposure index for a Hi Def camera (Any high def camera the DP shows up with without giving you any tech info on beforehand...like that never happens). Or, does anyone have a list of E.I's for various high def cameras?

I'm more of a film than video guy and having to crowd in for a look at the monitor while my meter sits in my bag is getting real irritating.

Dan LaBorde,

Gaffer.

Exposure Index for HD or any video camera is not entirely accurate since the sensitometric curve of film is so different to that of video. I find that the Sony camera floats somewhere between 320 and 800 depending on how I wish a scene to look. For sunny daytime exteriors it's closer to 320 but for moody night interiors I rate it closer to 800 because it sees so far into the shadows. The Panasonic has a similar range, although the response can be a bit different depending on whether you use the Film Gamma settings. Frankly there's so many adjustments that can be made in the different cameras that the only real way to know is to use a waveform and a well-calibrated monitor.

Mitch Gross

NYC DP

Dan LaBorde wrote:

>Anyone have a quick way to find an exposure index for a Hi Def camera

Set up a grey card and adjust the EI on your meter so that the stop matches the stop on the camera lens.

Best,

Anders Uhl

cinematographer

ICG, New York

Set up a grey card and adjust the EI on your meter so that the stop matches the stop on the camera lens.

I don't necessarily find this particularly accurate or useful myself. With film, once you find that magic spot where the grey card reads 18%, you might have 3-4 stops of over-exposure range and 3-4 stops of under-exposure range. In HD using the method you describe, I find I have maybe 1.5 stops over-exposure and as many as 5-6 stops underexposure (depending on settings). So even with this meter reading one still has to worry a lot about highlights blowing out and seriously adjust fill levels so the image doesn't look too "lit." Which means that the monitor is still very necessary.

Mitch Gross

NYC DP

I find that some folks simply can't relate all that well to exposing video with a monitor. As unscientific as it sounds, it is still the best and easiest way of judging exposure REGARDLESS of whether you are looking at a 9 inch or paying elephants to carry around those monstrous monitors I see folks using. Which makes me wonder, if for one hundred years, folks using film had a monitor to adjust exposure and then HD video came along and used a new fangled way of using a meter, would anyone bother buying one.

Walter Graff

Director/Cinematographer

HellGate Pictures, Inc.

www.film-and-video.com

Mitch Gross wrote :

>I find that the Sony camera floats somewhere between 320 and 800 >depending on how I wish a scene to look. For sunny daytime exteriors >it's closer to 320 but for moody night interiors I rate it closer to 800 >because it sees so far into the shadows.

I think Mitch is right, "EI" in each case depends on how the DP will approach it, what the post path is, is it for cinema/film out or television....

The concept of Exposure Index is to predict negative (well could be reversal/pos density) density of a film stock, there is pretty much an accepted methodology in printing that negative (nonetheless as we all know, even film exposure indices ain't written in stone), in video for any cinema purpose it can really depend on what they're gonna do & where they're gonna go with the signal recorded on the tape.

Sam Wells

>if for one hundred years, folks using film had a monitor to adjust >exposure and then HD video came along and used a new fangled way >of using a meter, would anyone bother buying one

Of course the reverse is that the Varicam has the excellent feature of a built-in spot meter, which will give an IRE reading to whatever is in the crosshairs. That is incredibly useful, often more telling than a waveform with all that info on the screen at once.

Mitch Gross

NYC DP

For setting HD exposure, nothing beats a waveform monitor and a large HD monitor in a proper viewing environment, but when you are on the run, the two zebras give excellent exposure results. I've been setting my first zebra to 71% and stopping down until they just disappear from the face; I've had no trouble with exposure using this method. Others rely on different percentages, measuring different areas, but this is what works for me.

For the jobs where only a smaller monitor is accessible, the little Sony 9" HD monitor is fine. By the way, I hate one feature of this monitor; when the Anton Bauer brick dies, the monitor makes a racket, and then turns itself back on after a bit with more noise. Does anyone know how to disable this "feature?"

I'm currently using a small Astro on the camera, but mine is an old model without the built-in waveform monitor. I think the new model might work well as an exposure guide and Panasonic also has a new on-camera LCD with a small waveform built-in. The Panasonic is attractively priced, though not a fully featured as the Astro. I've not tested the Panasonic LCD in my studio, only seen it at NAB, but I'm considering it as a replacement for the 9" Sony.

As has been said, the settings for HD cameras make the "ASA" of the camera an elusive, moving target. On the Varicam, for example, the Dynamic Level control varies the sensitivity by at least a full stop. Yes, you can get an approximation of the sensitivity for any given setting, and you can use that number when you are scouting or lighting a set/location to a desired stop. I've personally found that I can pretty much do that by eye, so my Spectra usually stays in the case; I certainly no longer need it to establish lighting ratios.

I do think a good spot meter is vital in lighting Blue/Green screens, but more than a few Cinematographers do very good jobs on this by eye. I always use the meter and the waveform monitor when lighting a screen.

Best regards to all,

Leo Ticheli

Director/Cinematographer

Birmingham/Atlanta

Re : [cml-lighting] HD exposure amazes me that with a technology that shows you the visual results right then and there, some people would RATHER take light level measurements, read some numbers, and then use their experience and imagination to predict the results -- and then consider this a more accurate way of working. What can be more accurate than simply seeing the image that the camera is capturing?

This is not a pro-video argument; I'm just suggesting that the notion that applying film techniques (metering) will lead to MORE accurate results when shooting video than using standard video techniques (monitors, zebras, waveforms, scopes) for judging the image. It seems to me that video's chief advantage is the reduction in the reliance of metering, making the experience of lighting and exposing more immediate. If I have to start metering everything when shooting video, I'd be asking myself why I wasn't just shooting film instead since I seemed to be wanting to deny myself one of video's true pleasures, the instant gratification of seeing the results of your lighting. Then you'd be in the WORST of both worlds : using a format with less exposure latitude and then having to rely on technical measurements to predict the results.

Anyway, with the way that video seems to vary in how it responds to low versus high light levels, I don't think picking an ASA value and always exposing by a meter reading -- while that can still work -- would be a more ACCURATE method than using something like a well-calibrated monitor and zebras in the viewfinder. On the other hand, for lighting a set without waiting for a monitor & camera to be set up, of course using your meter (and your eyes) is a good idea. It's just for final exposure decisions, I would use the monitor and zebras as a guide.

David Mullen

Cinematographer / L.A.

David M. said:

>What can be more accurate than simply seeing the image that the >camera is capturing?

Agreed!

I rarely ever pull out the meter when shooting HD. In fact I generally only do it to confirm my instincts (which are still developing) on ratios and such. The monitor is most certainly the way to go. I've also found that the "apparent ASA" not only fluctuates in dramatic changes like interiors to exteriors, but even within the same environment going through subtle changes in angle or focal length. There always seem to be slight fluctuations in sensitivity depending on the amount of luminance in any given shot.

Hence where while shooting film I like to settle on a 'stop' and light consistently for it, I find myself changing stops much more often for HD.

Roderick

Az. D.P.

www.restevens.com

12 On / 12 Off

Mitch Gross wrote :

>So even with this meter reading one still has to worry a lot about >highlights blowing out and seriously adjust fill levels so the image >doesn't look too "lit." Which means that the monitor is still very >necessary.

Sure, but for ratios and lighting it puts you in the ball park. I don't think anyone is actually metering for accurate camera exposure for video are they? It just helps to not be tethered to the monitor when roughing in the set. Me thinks.

I know that this thread has turned into a discussion of camera exposure and "why use a meter when you've got the monitor", but the original poster was a gaffer and has a very valid point in implying that it is inefficient to be running to the monitor ("crowding around") when he could be making evaluations on the floor.

Best,

Anders Uhl

cinematographer

ICG, New York

Interesting discussion this. Last week I shot a food commercial on a digital format, just the table top, kitchen backgrounds and products for some CGI animation to jump about on. I almost didn't take my meter that morning and actually went back into my house to pick it up for some strange, perhaps comfort, reason. During the set up there were some differences in the shadow areas in the foreground which we couldn't seem to rectify using the monitor.

Out came the meter and bobs your uncle. Lighting the kitchen background was easier using a monitor though, as was getting a shallow depth of field we were all happy with. I think I looked in the camera only once, seeing as there was no operating to be done.

Just my three pennies worth

Chris Maris

UKDP

www.chrismaris.com

>During the set up there were some differences in the shadow areas in >the foreground which we couldn't seem to rectify using the monitor.

Certainly that's one the practical applications of a meter -- to light areas of a set to matching levels. It's a lot easier to walk around with your meter and balance the light level to the same stop than eyeball it on a monitor. On the other hand, if it looks good on the monitor, perhaps it didn't need to be perfectly balanced...

But if I were going to light a long Steadicam shot where I wanted a person to pass under multiple pools of light that were at the same level, I would use a meter whether it was for HD or film.

David Mullen

Cinematographer / L.A.

>On the other hand, for lighting a set without waiting for a monitor & >camera to be set up, of course using your meter (and your eyes) is a >good idea

Here's an instance of the top of my head, in lighting for video, where I might have profited slightly by using a meter: we're using natural daylight from one medium sized window to light / fill half a room, small soft lighting flexible units on the other side. We decided - time factor, rigging, plus the light looked good and no chance of direct sun....To go this route. In fact it looked quite natural and nice.

Mid afternoon and then after about 1 hr or more the DP says to me "do you think we've lost any of the daylight ?" I look at it and the monitor and say "no it's the same" --- an hour after that he says "have we lost any yet" and I say "a little" and then "1/ 2 stop maybe, no more" --- and at the end of this setup I think I said "it's probably close to or even a full stop less than when we began"

All was fine but I remember thinking "hmm a meter would confirm my intuition" yes one could borrow the camera to use as a meter but you know how it goes on a hurried set, everyone wants the camera at once....

Sam Wells

I've lit quite a few video jobs where you don't have a monitor to look at until it's too late. Usually big pre-light jobs. In that case you only have a meter and your eye to rely on.

Phil Badger

gaffer, LA

http://home.earthlink.net/~badger111/index.html

>But if I were going to light a long Steadicam shot where I wanted a >person to pass under multiple pools of light that were at the same level, >I would use a meter whether it was for HD or film.

Might be good but with video I'd probably still have a stand in do the walk and make sure it works, but the meter certainly could be useful here.

Walter Graff

Director/Cinematographer

Had a dinner scene with six people around a table, keyed with a China ball with a photoflood inside. Photofloods die over time, plus for each close-up I wanted a relatively closely matching key level even though it was a rectangular table that normally would not allow this. I used my light meter to make sure levels remained consistent during the course of a long night and many, many angles.

Mitch Gross

NYC DP

I think if the point of metering HD is not for final exposure decisions but for matching and balancing lighting levels, then it really doesn't matter if the ASA you chose to light to EXACTLY matches the HD camera, unless you are trying to light as closely as possible to some predetermined f/stop that you want to set the lens to (like near wide-open.)

Often when lighting for HD, I might set my meter to 400 ASA, let's say, not because that's exactly correct but it is fine if all I'm doing is using the meter to match key or fill levels of various instruments, for example. As long as you are within a half-stop on your meter to the camera's sensitivity, you'll probably be fine in most lighting scenarios (and in general, you'll probably be lighting to a slightly higher level than needed and then scrimming down to the final level, on the theory that it's better to have a little too much light than being a little short of your needed exposure...)

Anyway, if all the gaffer needs is a ballpark ASA equivalent, he can probably do that right on the set with the camera and a grey card to find a setting for his meter that is close enough to be practical. He and his DP should probably come to some agreement anyway as to what ASA they want to work at.

David Mullen

Cinematographer / L.A.

Mitch Gross writes :

>Had a dinner scene with six people around a table, keyed with a China >ball with a photoflood inside. Photofloods die over time

One safe alternative to a photoflood in a China ball would be a fourplex lamp socket (star configuration) with four 100W Sylvania Capsylite bulbs. Being halogen, they won't go dim or yellow over time. And being encased in a thick (nearly unbreakable) glass outer envelope they don't have the explosion/fire-hazard factor of bare halogens.

If your light needs to be somewhat directional, you can add an internal reflector made of Reflectix insulation. This will also give you about an extra stop of light output. And you can rotate the ball to control the relative illumination on different parts of the scene.

Dan Drasin

Producer/DP

Marin County, CA

Indeed, I always have my meter when I know there'll be no waveform monitor, regardless of having a decent monitor on set. At least I can confirm light to shadow values, especially outdoors.

Best Regards,

Nick Mueller

Director of Photography

Washington, D.C.

I'm impressed, I'm going to have to totally revise my presentation for IBC as a result of this thread.

I hadn't realised that nobody pre-lit when shooting HD.

I hadn't realised that nobody shot simultaneously on multiple sets on HD, my personal record is 8 sets on 3 stages all to match identically.

I hadn't realised that nobody went back to get pickups months, or in one case over a year, later on HD.

I didn't realise that nobody shot second unit that had to match the first units work on HD.

I didn't realise that you always had ideal and matching viewing conditions on every set and every day when you shot HD.

I didn't realise that you carried all the rushes with you all the time and had duplicates of everything made for every unit on the shoot when you shot HD.

So much I don't know, I'll have to pull out of IBC.

It's so different shooting HD, I had no idea!

Cheers

Geoff Boyle FBKS

Director of Photography

EU based

www.cinematography.net

Geoff Boyle wrote :

>I hadn't realised that nobody pre-lit when shooting HD. I hadn't realised >that nobody shot simultaneously on multiple sets on HD, my personal >record is 8 sets on 3 stages all to match identically.

Wow, Listmums are crackling these days. First Jessica yesterday, now Geoff. I've tried to express the same thing in the past myself.

As for HD cameras changing "ASA", Yeah I 'm sure they can if you play with the gain structure or cheat Gammas, but my experience is that they are remarkably consistent no matter what, if you don't twiddle.

Mark Smith DP

Oh Seven Films Inc.

My personal view is that nothing beats having a light meter during complex set-ups. A great monitor and waveform are wonderful, but it's just not possible when you're on the move or before the camera arrives. Here's how I've been ascertaining relative film speed numbers for video cameras of all kinds (NTSC or HD).

Have the video engineer set up the camera on a grey scale chart (which typically has 11 steps ranging from a reflective value of 2% to 90% on a 12% background). Allow the engineer to adjust the camera for best exposure across the entire range of chips. The lens should be around the middle of its zoom range during this charting for reasons addressed below.

Then take an incident light reading on the chart, note the aperture on the camera lens (along with any gain settings and filter) and work the numbers to provide you with a correlated film speed. As long as the gain settings and filters remain the same, you can depend on the speed remaining constant throughout the day.

The only variable that might throw your readings will be due to F-stop ramping. Most video lenses have pronounced F-Stop ramping at the extreme ends of the zoom range. You will lose light at the furthest telephoto range and gain light at the widest angles. Few video lenses can be depended on for T-Stop accuracy.

This technique has provided me with consistent and dependable results when working with video. Your experience with the particular camera (and the way that your engineer sets it up) will provide you with dependable exposure latitude information.

Another important tool is a "God" monitor and a waveform. The best situation is to have your own monitor who's set up is consistent and dependable. The monitor is your subjective "light meter". It ultimately answers the question of "Does it look good?"

The waveform is your empirical measurement that shows you what the camera is really seeing. It pays to learn how to read a waveform so that you can know when there is a problem, particularly at the upper and lower range of the exposure.

That's my two-bits.

Bruce Aleksander

LD/DP and whatever else it takes to get through today

ABC / Disney

Houston, Texas

>As for HD cameras changing "ASA", Yeah I 'm sure they can if you play >with the gain structure or cheat Gammas, but my experience is that they >are remarkably consistent no matter what, if you don't twiddle.

Mark, I think it's not about the consistency of the cameras, it's about where you assign tonal values for cinema finish...

Sam Wells

>my experience is that they are remarkably consistent no matter what, if >you don't twiddle.

Yea, scratching my head too!

Walter Graff

Director/Cinematographer

HellGate Pictures, Inc.

Bruce wrote :

>It pays to learn how to read a waveform so that you can know when >there is a problem, particularly at the upper and lower range of the >exposure.

Bruce's advice on working with your engineer to establish working parameters is excellent. I would add that the waveform not only allows you to confirm values and ratios, but will quickly give you a heads up when the camera head develops technical problems; i.e. timing, sync, phase, a board on the verge of failure, etc., allowing you and/or your DIT to make more informed decisions.

Thanks for the good advice, Bruce

Regards,

Nick Mueller

Director of Photography

Washington, D.C.

>,,,,,the Varicam has the excellent feature of a built-in spot meter, which >will give an IRE reading to whatever is in the crosshairs.,,,,

Remember the TK-76 with the waveform overlay...rotated ninety degrees for some strange reason? Bizarre implementation of a great idea.

It would be *fantastic* if we could touch a momentary switch and have a greyed-out picture with a white (peak oriented) waveform display in the viewfinder.

David Perrault, csc

>It would be *fantastic* if we could touch a momentary switch and have >a out-out picture with a white (peak oriented) waveform display in the >viewfinder.

What a great idea! I'd like to see professional cameras with a flip out LCD's on the side too - I frequently operate cameras which are rigged in unusual positions, and a side LCD makes operating the camera in those situations a lot easier.

Jessica Gallant

Los Angeles based Director of Photography

West Coast Systems Administrator, Cinematography Mailing List

https://cinematography.net/

I don't know the last time I took out a camera - film or video - without sticking an LCD off an Israeli Arm onto it. I simply ALWAYS operate in this mode. If I'm not using it then it's always good for my assistant or convenient for the client. I frankly don't have a problem with the cameras not having one built in since that is technology that is changing very fast and is fairly cheap. I'd rather have a better add-on display than a mediocre built-in one, although I guess I could always add a better screen to a camera with one built in.

Mitch Gross

NYC DP

I see it as a few problems.

First these cameras are designed as ENG cameras. No room for the circuitry for putting a waveform.

Second, these cameras are designed as ENG cameras, no need for a waveform.

Third, these cameras are designed as ENG cameras, you want a waveform, go buy one.

Forth, these cameras are designed as ENG cameras, what's the matter with zebras?

Walter Graff

Director/Cinematographer

Walter Graff NY wrote :

>Forth, these cameras are designed as ENG cameras, what's the matter >with zebras?

Why do people think that these cameras need a waveform? The Zebras work perfectly fine. They also don't need a flip out LCD, that's what you get the onboard monitor for.

When was the last time that you saw a Waveform and Flip out LCD on a film camera and we have been making perfectly fine pictures with them for the last 100 or so years....

Eric Fletcher SOC

Steadicam/"A" Camera Operator

Los Angeles, CA USA

Eric Fletcher wrote :

>When was the last time that you saw a Waveform and Flip out LCD on a >film camera and we have been making perfectly fine pictures with them >for the last 100 or so years....

Asking an engineer if you need a WFM is like asking a barber if you need a haircut.

Brian Heller

IA 600 DP

>Asking an engineer if you need a WFM is like asking a barber if you >need a haircut.

The real question is who brought back the engineer anyway. Half of these so called 'engineers' or that other title I often see are simply AC's trying to keep a job. Ask them what a front porch is and they'll tell you a place to whittle wood.

Walter Graff

Director/Cinematographer

When was the last time that you saw a Waveform and Flip out LCD on a film camera and we have been making perfectly fine pictures with them for the last 100 or so years....

Yeah, and who needs that fancy-shmancy reflex viewfinder? Greg Tolland didn't need one for Citizen Kane?

Mitch Gross

NYC DP

....When was the last time that you saw a Waveform and Flip out LCD on a film camera and we have been making perfectly fine pictures with them for the last 100 or so years....

True, although for quite a while now film cameras have had video taps and little flat screen monitors attached for focus pulling ease.

I have a tiny little canon mini DV thingy camera which fits in my pocket that I use for all sorts of things from filming my kids to checking locations. It has a flip out screen which is great, I love it.

Just because such things on ENG cameras haven't existed before, why not now? The eyepiece B&W screens are a pain in the arse anyway.

Or am I missing something in this debate.

Chris Maris

UKDP

>Just because such things on ENG cameras haven't existed before, why >not = now? The eyepiece B&W screens are a pain in the arse anyway.

Because the ENG market doesn't need them. Professional ENG shooters know everything about exposure from experience and wouldn't want one let alone know how to use one. 99% of video cameras are for ENG purposes so to try to get an industry change because a few folks want extras isn't in the picture.

Having used a color viewfinder on a professional camera I can personally say

thank god for black and white viewfinders.

Walter Graff

Director/Cinematographer

>Because the ENG market doesn't need them. Professional ENG >shooters know everything about exposure from experience and wouldn't >want one let alone know how to use one.

Of course, but sometimes...I was using a "professional ENG" camera today and the damned thing had to be so high up and the director was hogging the monitor that a flip-out-tilt-down-screen would have helped me with the operating a little bit, colour or black and white.

Regards

Chris 'I don't make presumptions' Maris

>Of course, but sometimes...I was using a "professional ENG" camera >today and the damned thing had to be so high up and the director was >hogging the monitor that a flip-out-tilt-down-screen would have helped >me with the operating a little bit, colour or black and white.

Still ain't gonna make the market change.

Walter Graff

Director/Cinematographer

WalterNY wrote :

>Because the ENG market doesn't need them...thank god for black and >white viewfinders.

It's all been Down Hill since the HL77 and TK76. They were good enough. Why bother improving?

Sure be nice if we had a chat thread for all this chat nonsense.

Steven Bradford

Seattle

Mitch Gross writes :

>who needs that fancy-shmancy reflex viewfinder? Greg Tolland didn't >need one for Citizen Kane?

I prefer the old reliable wire frames, myself. They're much lighter than those clunky old Mitchell finders, and have absolutely the highest resolution, greatest depth of field and most impeccable color rendering of any finder system before or since. Parallax? Just shift your head a bit -- no need to futz with those pesky adjustment knobs and scales.

(Well, some of the more advanced wire-frame finders do have parallax scales, but who needs 'em?)

If the folks at Thomson had their heads screwed on straight they'd provide one for the Viper. But they'll probably never think of it.

Dan "finders keepers" Drasin

Producer/DP

Marin County, CA

Steven Bradford wrote :

>It's all been Down Hill since the HL77 and TK76. They were good >enough.

TK76 good enough! Ouch! My back says different. For that matter lets go back to BVU110's and while were at it how bout Cine60 "diver weights" light belts.

So how much wattage were you using to light intvws for a TK76?

Tom "remembers magnacyte(spelling)" McDonnell

New Orleans, La

When was the last time that you saw a Waveform and Flip out LCD on a film camera and we have been making perfectly fine pictures with them for the last 100 or so years....

Yeah, and who needs that fancy-shmancy reflex viewfinder? Greg Tolland didn't need one for Citizen Kane?

Sound? Lots of great movies were made without sound!

Roderick

Az. D.P.

12 On / 12 Off

>When was the last time that you saw a Waveform and Flip out LCD on a >film camera and we have been making perfectly fine pictures with them >for the last 100 or so years....

Sony's new Optical camera has a flip out screen on the operators side (flimsy feeling) but no waveform.

Walter Graff

Director/Cinematographer