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Dark Side Of The Light Meter

Published : 13th June 2004


Hello everybody,

I recently joined this forum and I've been learning a lot since then. As a token of my gratitude I'm here to share some of my confusion for the first time. Please go easy on me...

Few weeks ago I decided that it was about time to start saving on ice cream and to spend some money on one or two good light meters. During my investigation I've noticed that the specs of all the meters that I've been able to look at, lack a very important piece of information, that is their spectral response. I've written to Minolta, Sekonic and Gossen asking for their meters' SR but I didn't get any answer. The only information about the SR of a meter I've been able to find is for the Zone VI modified Pentax Digital Spot Meter that is calibrated to be used with Kodak Tri-X B&W still photography film, and that film's spectral sensitivity chart can be easily found on the Kodak website.

All this led me to think that, if the manufacturers don't provide any SR for their meters, it's probably because they're flat, so when I use an incident meter I shouldn't worry too much about its SR and when I use a spot meter I just have to compensate by eye for the SS of the film stock I'm using. To confirm my hypothesis I tested a couple of meters that I could get my hands on by taking B&W stills of plates of different very saturated colors. My empirical observations led me to realize that the spectral response of those meters is far from being flat, with some giving ridiculous readings toward the blue end of the visible spectrum. My means (not to talk about my knowledge) were too rudimentary to get any further than this simple conclusion.

Just not to seem too foolish, before writing this email I tried to find an answer to my questions on several books like the ACM, both Blain Brown's books and several others but I haven't been lucky. The only book where I've found some, but not much, useful information on the subject is Ansel Adams' The Negative.

Even if not directly related to the meters' SR, a disconcerting discovery I made on Ansel Adams' book is that even if the light meters manufacturers tell you their meters are calibrated to 18% grey they are not. Apparently almost all meters include a 'K-factor' that makes them read to a grey that is usually between 10% and 18%. If I'm not mistaken, only Sekonic acknowledges this in its meters specs. Anyway, at least once you know this fact, it's easy to compensate...

In conclusion, all I can say is that I'm confused and at the same time I'm sure I'm overlooking something. Is there someone kind enough out there that can shed some light on the subject?

Thanks

Simone "I just wanted to buy a meter or two" Rapisarda
Montreal, Canada



Hello -

I actually just bought another meter today. My nice little studio deluxe II just didn’t cut it for some of the low light photography/cinematography I’ve been finding myself doing. My take on this situation is that I don’t think it really maters what meter you get. They all work quite nicely.

I picked up a used Spectra IV-A for a couple of simple reasons. It fits nicely in my hand, it doesn’t have many moving parts to accidentally bump or press like those damn Sekonic “do it all” meters, it’s simple to use, it’s easy to read, it cost $200.00, and last but most important – I just like it better then other incident meters for some other unknown reason.

I’ve see pictures of Storaro using a studio deluxe II, Nykvist with a Pentax digital spot meter (zone VI maybe?), Almendros with a Luna Pro, Conrad Hall and Michel Chapman with the old Spectra Pro, and most of the DP´s I work for with those darn “do it alls” that I dislike so much. So my advice is to buy the meter that fits your personality and metering style. I’m still bent on buying a Pentax digital spot since I’ve raised myself analog spot metering through my old manual SLR over the past 7 or 8 years.

Using incident meters just doesn’t feel the same (but I just bought that Spectra! What was I thinking?...I was thinking that I don’t have $500+ to blow on a Zone VI meter at this moment in time).

I’m sorry if none of this helped you in any way, but it’s my take on the “what meter should I buy” issue.

Good luck,

Joe Zovko
AC
LA, CA



>if the manufacturers don't provide any SR for their meters, it's probably >because they're flat, so when I use an incident meter I shouldn't worry >too much about its SR

They are far from flat, although they don't seem to be as bad as they used to be. Mark Woods is probably the person to ask about this; perhaps we'll hear from him.

The very general rule of thumb I've always used is that at the extreme ends of the spectrum (very red or very blue) meters tend to be less reliable and it's time to go to a Polaroid. I wonder if others take a similar approach.

Certainly, if you find this information, please share it with everyone.

Search the CML website, it might already be there.

>Even if not directly related to the meters' SR, a disconcerting discovery I >made on Ansel Adams' book is that even if the light meters >manufacturers tell you their meters are calibrated to 18% grey they are >not.

Also, as you know from Adams, ultimately, the final calibration is by you using the film stocks and conditions under which you normally operate. This is probably why most DP´s don't worry too much about exact spectral response charts or sensitivity curves published for film stocks : except in a very general way. It's the actual use that counts.

Testing is everything.

You can obtain most Kodak or Fuji film stocks in still camera cassettes, test them and have them developed as slides or prints. This is probably the best way to test them if you don't have ready access to a camera. Be rigorous in your testing and it will reveal just about everything you need to know about the meter and perhaps more importantly your metering technique. (If you can't find them in Montreal, they can be obtained from RGB Labs in Hollywood. They also do the processing.)

In your case, pay particular attention to extremes of lighting conditions : reds at one end and blue/violet at the other; also sodium-vapour, mercury vapour, other sources that are not full spectrum, etc. Include a grey scale and, if you can, a Macbeth color chart in each scene you shoot (very important in the extreme color conditions to understand not only how the meter responds but how the film responds).

If you can, also take a Polaroid and include notes on the incident reading, where you set the stop and perhaps most important : reflectance/spot readings of the shadows and highlights. This is a film education in itself.

Processing them as slides is the most important, but the prints can be useful for other purposes. Be sure to examine the original negative as well. Mark Woods does his analysis on a densitometer; perhaps your local lab can help you with that. For extreme color conditions and evaluating the meter's response, this would be very useful. Learning to recognize a solid negative by eye is a valuable skill in any case. Be sure to shoot some over and under exposures for comparison.

Do the tests carefully and share the results and you will earn the gratitude of your fellow cinematographers. Finding charts from the manufacturers is not likely to be easy; I've tried. Even if I had these charts, I'm not sure I would have included them in the books except as a rough starting point: ultimately it is the testing by each individual that is the ultimate calibration. Look at Mark's website for the excellent work he did with film response at sunset — extremely valuable research. I think there is a link at CML.

Very commendable that you did the tests with the color plates. I think you will find that B&W film is more sensitive to extreme color conditions than is color film, particularly at the upper end. One of the most intriguing aspects of the Zone Six calibrated meter is the ultraviolet filter : very useful at high altitude. Keep in mind, however, that meter is specifically designed for black-and-white zone system work.

For color negative work in film, quite frankly, the techniques are not nearly so exacting. Usually, in film, it's more about controlling the lighting than about controlling the negative in the darkroom. (Certainly, I am in NO way implying that careful metering is not important, in fact, I'm a bit of a nut about it myself. I come from a Zone System background myself.)

Good luck

Blain
DP
LA



>The very general rule of thumb I've always used is that at the extreme >ends of the spectrum (very red or very blue) meters tend to be less >reliable and it's time to go to a Polaroid. I wonder if others take a similar >approach.

Who's to say (without extensive testing) that Polaroid B&W film had the spectral response that matches the color film we use today. Metering for exposure is a subject and interpretive art. Since I only use Minolta Digital Spot Meters and the Last Gray Card (yes, I calibrate to it. So who cares what percentage reflectance it is, just so it is consistent) I have found that the few anomalies that I see are not enough to offset exposure a whole heck of a lot. If I'm doing something wildly to either end of the spectrum I test it. And If I can't I allow an intuitive overexposure for deep reds and deep greens.

Minolta has always been very responsive to my technical questions (even when I was just getting started). After the (American holiday) weekend I will call them and try to report an individual that you can contact for information. They even sent me a chart that showed the offset for primary red light. Also, I always found the old mechanical meters completely unreliable. Depending on how you held them you could get widely varying readings because of the weight and balance of the needle. And if you breathed on them funny they would go out of calibration. Very touchy.

I think the onset of digital metering (no matter what the spectral response) was a boon to the photographic process. Remember, when you were working with ASA 25 film you could be off 100 or so foot candles and still get decent exposure. But with 500 ASA just a few foot candles can mean a significant exposure difference.

Steven Poster ASC



Steven Poster ASC wrote :

>I think the onset of digital metering (no matter what the spectral >response) was a boon to the photographic process. Remember, when >you were working with ASA 25 film you could be off 100 or so foot >candles and still get decent exposure.

I wonder if anyone still remembers the extinguishing type meter. I inherited one from Roy Tash csc (died 1988 I think, well-known cameraman) who used one since he started in the News Camera business back in 1916. Roy never used anything else, yet his exposure was always dead on-he was known for it.

This one has 1922 engraved on it. In short, you compared the light with a corresponding filter. I think it was called E.I. then, exposure index and it was calibrated to ASA 16, or the equivalent of whatever the E.I said. I used it on several occasions and found it highly accurate, at least with Gevaert reversal stock. Never pursued it however, naturally I would not want to be found dead using it, I had a Spectra. True enough, the Spectra was often inaccurate in case you held it on its side, especially at 40 below in Edmonton and points north. Then I used the extinguishing meter, was always dead on in snow conditions, specially on slow speed stock...

Robert Rouveroy csc
The Hague, Holland

I plan to live forever. So far, so good.



>Who's to say (without extensive testing) that Polaroid B&W film had the >spectral response that matches the color film we use today.

For situations like that I generally use color Polaroid (for normal scenes I use the high speed black and white). I tend not to use Polaroid nearly as much as I used to, except for green screen work.

Your statement is certainly correct but I'd have to say that I have tested it, not to a level of scientific accuracy, but enough to satisfy me that it works for my use. I certainly concur that the old mechanical meters were much further off. I've been aware of it since my Photography 101 teacher many years ago told a story about shooting Peggy Lee in a nightclub under red spotlights and getting burned on the exposure.

When I'm in doubt about a heavily coloured scene, I used to read with the Minolta digital, the old Spectra mechanical meter and also with the Pentax spot meter with a grey card (and have the gaffer read with his meter also) - none of them agree, of course. (I rarely use the old Spectra anymore; as you say, it is not very reliable or accurate, certainly not for this kind of situation.)

The differences in the readings for the three meters are quite interesting: and unnerving (especially early in your career). Consistently, I've found that the Polaroid is the most accurate and generally agrees more closely with the digital meter than the mechanical — but not completely. Can't claim scientific accuracy but for my own use it seems to work pretty well; to date I've never had an exposure problem with heavily coloured scenes; except once.

It was a scene in a Chinese restaurant: a meeting of the Chinatown elders. In rehearsal I noticed that the large neon sign in the window spread this wonderful deep orange glow over their faces (they were at a table by the window).

Beautiful, moody, mysterious light but at the bottom end of exposure (way off the bottom end according to the Spectra, closer but not quite on the Minolta and Pentax). I got the gaffer started on building a rig that would duplicate the look as closely as we could.

Then I decided to be a bit bold and I took a Polaroid. I told the gaffer to stop (we were also running out of time on the permit and the SAG actors were perilously close to overtime). The Polaroid told me I could do it when the meters said "don't be ridiculous."

A while later there were shake-ups (director fired in post, that sort of thing) and I got a call from the producer "We're having trouble with the scene, the lab thinks it's underexposed." This is the call that every DP dreads.

He told me "We had a hell of time getting all the orange out of it and when they did, it's all grainy and underexposed." I explained (as calmly as I could) that there was nothing BUT orange in the scene and if you take it all out, there is very little image left at all. They reprinted and it worked fine; still my favourite shot in the movie.

So bottom line in this situation: couldn't trust the meters in this case. The Polaroid, if nothing else, emboldened me to "go for it." What appeared to the producer to be an exposure problem turned out not to be.

That's really the story with meters, Polaroids, grey cards, etc: every DP uses them in their own way - factoring in their own experience and calibration adjustments.

It really gets back to the "personal calibration" that is at the heart of the Zone System. Back when I was a gaffer I saw DP´s use meters in some pretty idiosyncratic ways: it sometimes seemed that the more famous the cameraman, the more unusual his metering method; but obviously it worked for them.

Blain Brown
DP
LA



> I wonder if anyone still remembers the extinguishing type meter.

I was given an Extinguishing Meter by my mentor, Ralph Woolsey, ASC. It is a Bell & Howell manufacture, but I've never been able to find any information on operating it. Its been languishing in my Closet of Strange Film Chunks the past 15 years or more -- can't bring myself to throw it away, though.

Gerry Williams
Director of Photography
San Diego, CA

"Living on Earth is expensive, but it includes a free trip around the sun."



Blain Brown wrote :

>The very general rule of thumb I've always used is that at the extreme >ends of the spectrum (very red or very blue) meters tend to be less >reliable and it's time to go to a Polaroid. I wonder if others take a similar >approach.

Definitely, I've found ALL meters to be unreliable with both Green & Blue screens and with measuring TV or computer screens.

Video assist, a good one, can be very useful with the extremes as well. I always use the VA for balancing TV screens that are in set.

And by ALL meters, well I'm a bit of a meter freak. I've got Spectra's, Minolta's, Sekonics, Gossens, Pentax and err.....

I use the Pentax digital spot for most screen work as it seems to be the least sensitive to extreme colour but always use the Polaroid 600SE when in doubt!

I'm currently using the Minolta 6 as my standard meter, a lovely toy.

Cheers

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



Robert Rouveroy csc writes :

> I wonder if anyone still remembers the extinguishing type meter.


I have one that I bought in a "antique's" shop on the quayside in Exeter, it cost me a whole $4

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based



Geoff Boyle writes :

>Definitely, I've found ALL meters to be unreliable with both Green & >Blue screens and with measuring TV or computer screens.

>And by ALL meters, well I'm a bit of a meter freak. I've got Spectra's, >Minolta's, Sekonics, Gossens, Pentax and err...


Have you tried that marvel of British engineering known as the SEI (Salford Electrical Instruments). For the uninitiated, it is a 1/2 degree spot meter that uses the extinguishing method, except that it contains its own comparison lamp and calibration circuit.

It is extremely accurate and since it does not use a photo cell, it is immune to extremes of color.

The drawbacks are that the image is inverted and it is not easy to use and in their day, they were very expensive. I don't think Salford is still around, but the meters do crop up at used equipment shows from time to time.

No collection is complete without one.

Brian Heller
IA 600 DP



Brian Heller wrote :

>Have you tried that marvel of British engineering known as the SEI >(Salford Electrical Instruments). For the uninitiated, it is a 1/2 degree >spot meter that uses the extinguishing method, except that it contains its >own comparison lamp and calibration circuit

We got one in 1956 and I used it for about 35 or 40 years, mainly in photographing old masters. The painters painted very deep, tonally, and a "pure white" in the painting would be somewhere in the vicinity of perhaps 25% reflectance. SEI had the only spot meter out there in those pre-CdS meter days, so it was the only game in town. Very reliable once you learned how to match the illuminated spot to tones that were not necessarily neutral.

Unfortunately, a "leak proof" Eveready cell leaked into it and ruined the meter. Fortunately, Eveready was as good as their word and replaced it with a Zone VI Pentax at our request, the SEI being long out of manufacture. Frankly, I prefer the Zone VI (it's an analog model) to our Pentax digital. I just prefer seeing the needle indicating a very specific reading, instead of the digital's f/number plus or minus 1/3 stop LEDs. The digital is more compact and you can see the readout when reading in very dim light, but it doesn't like chopped light, like regular fluorescents. You can read subjects illuminated by fluorescents, but when you try to read the tubes themselves the reading oscillates. OTOH, the analog’s scale disappears when you try to read a spotlighted subject with a dark surround. The scale in the dark. And there is no way to tell if the needle zeroes when there is no light. With both meters the spot itself is very hard to find when trying to read very dark subjects. I have to move the meter around trying to locate the spot, then guide it to the subject. The digital meter is more than 10 years old, so maybe that aspect has been improved.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614



> extinguishing type meter

I've heard of these but never seen one. How do they work?

Blain Brown
DP
LA



Blain asked:

> extinguishing type meter

>I've heard of these but never seen one. How do they work?


They consisted of a viewing port or ports through which the scene could be viewed through a progressive series of ND filters. You ran through the ND filters until you came to one that just extinguished the view and that gave you a reference number to dial in for your exposure. Sort of a calibrated contrast viewing filter. And like the viewing filter, your eyes had to be adapted to the scene's light level and you couldn't view through it long enough to allow your eyes to accommodate to it.


Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614



Brian Heller wrote :

> No collection is complete without one

I used to have one, but sadly let it slip from my fingers...

Jeff "only has a minor collection of light meters" Kreines



You are right about the SR vagaries...and it is even worse than that.

Individual meters are calibrated before being sent out (theoretically) at a specified color temp, so the fact is, if you use that meter to look at very different colour temp continuous spectrum sources or ANY spikey sources, you will not be getting accurate info...of course if you test test test, the inaccurate info is still quite useful. Hence the need to test when using a lot of very saturated primaries, especially red and blue.

Two different meters of the same manufacture and design using photocells from different production runs will be calibrated to match at their calibration color temp but may vary from each other at other color temps.

The old spectra pros and candelas were calibrated at 3200K

I believe that Sekonics or Gossen Luna Pros (one or the other or maybe both) are calibrated at 4300 or 4800 - somewhere between tungsten and daylight...so that they can be said to be reading "correctly" even if they do not agree with a spectra at daylight for instance.

Naturally, most flash meters are calibrated at 5500 kelvin since that is close to where the strobes are firing

If this looks messy, it is because it IS messy. The reality is that shooting color neg, I never got bit by the inaccuracy of my tungsten calibrated mechanical meters when I used them outdoors, but the fact is, I should probably have used it with an 85

I believe that the modern Spectra Pro IV A is still calibrated at 3200K but a call to them would answer that for sure.

In practice with color neg, it doesn't matter much unless you get into very high or low color temperatures - but you can get way off with strongly filtered light sources - very saturated coloured gel, for instance.

Some people use B&W Polaroid film to test - this can help but may not give you dead nuts accuracy since the spectral response of that film may not match your color neg stock.

As someone mentioned, you can shoot tests by putting 35mm motion picture stock in a still camera and shooting exposure wedges to see how your meter differs from the film's response at wide color temp differences. If you shoot a gray scale at different color temperatures you can look at the different chips with a densitometer and compare density of the neg compared to your meter readings.

This might well end up to be more interesting than useful, but different people use meters very differently in their photographic process, so part of the game for a lot of people, (self included) is to learn what the tools tell you so you know when to trust them and when not to.

Mark Weingartner

P.S. I just bought another electronic spectra - I still have not found a digital meter that suits ME better...to each his own.



First of all, I would like to thank everybody that answered my post. I've found the thread deeply instructive! In the hope that I'm not abusing of you patience, I'd like to add few more lines on the subject.

>Certainly, if you find this information, please share it with everyone. >Search the CML website, it might already be there.

I did a search on the CML archives and also on Google before writing my cry for help. I didn't find anything that I thought was relevant except for some articles on the www.photo.net archives were few years ago several Zone System photographers were discussing the issue. But maybe this can be due to the fact that I'm not that skilled with lucky search keywords. Anyway, among these photographers there was a certain Tom Johnston that seemed a very knowledgeable individual, he once published an article on the subject in the now defunct Camera & Darkroom magazine. He apparently tested all the meters available on the market at that time for their spectral response.

All that I know is that, as a result of those tests, there were only two meters he recommended : The Zone VI modified Pentax digital spot meter and the Minolta Flash Meter IV (the V was already out...). I've played with the IV at a second hand shop and it takes at least one second before giving you the result of the reading. My thought is that Minolta wanted the V to be a faster meter (for continuous readings) and decided to sacrifice accuracy to gain in responsiveness.

>[...] Finding charts from the manufacturers is not likely to be easy; I've >tried. Even if I had these charts, I'm not sure I would have included them >in the books except as a rough starting point: ultimately it is the testing >by each individual that is the ultimate calibration.

Ok, I agree with that, but, I find that, aside for the Adams books, all the other books I've looked at are describing the light meters as perfect tools. Some of them go as far as explaining the Zone System adapted for cinematography without spending a single word on the meters' idiosyncrasies. And that can make someone that is learning the trade, like myself, pretty frustrated. Anyway, I shouldn't complain too much, because I have to admit that I learned a lot from those books.

>Look at Mark's website for the excellent work he did with film response >at sunset extremely valuable research. I think there is a link at CML.

Are you talking about the articles on www.cameraguild.com? They look pretty interesting, I'll surely going to read them in the coming days. Thanks!

>Video assist, a good one, can be very useful with the extremes as well.

BTW, is it possible to use with any success a digital camera to do that?

In conclusion, having to face the crude reality, that is that the perfect meter doesn't exist, my intention is still to buy an incident and a spot meter that are as reliable as possible and then build on that with my experience as you guys are suggesting me to do. I'm still trying to avoid to start a collection (even if apparently it looks like the best way to go...

Thanks again to all of you!

Simone A. Rapisarda
Montreal, Canada



Mark Weingartner writes :

>This might well end up to be more interesting than useful, but different >people use meters very differently in their photographic process

I've had a number of assistants and students accuse me of deciding what stop I want and then waving the meter around taking different readings until I get one I like.

Well I do, sort of, it's that experience thing, I take lots of readings, incident and spot, and then integrate them in my head.

So it's true " you give us a stop of 4 but you never got 4 on the meter, everything but!"

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based



Simone A. Rapisarda writes :

>I did a search on the CML archives

Ah but did you also use the search all edited pages facility?

This is a new and under-used facility.

Cheers

Geoff Boyle FBKS
Director of Photography
EU Based



Phil Rhodes writes:

>Well see you film guys can get away with it, bitch grumble moan... it >seems to me that you can stick 5218 in the camera and so long as >you're within five or six stops there's liable to be at least some kind of >image!

Damn, the secret is out.

Of course vidiots don't even need to learn how to wave a meter around -- just point and shoot...

Brian "When in doubt, shoot at 5.6" Heller
IA 600 DP



Hi,

>I've had a number of assistants and students accuse me of deciding >what stop I want and then waving the meter around taking different >readings until I get one I like

Well see you film guys can get away with it, bitch grumble moan... it seems to me that you can stick 5218 in the camera and so long as you're within five or six stops there's liable to be at least some kind of image!

Phil Rhodes
Video camera/edit
London



Phil Rhodes writes :

>Well see you film guys can get away with it, bitch grumble moan...it >seems to me that you can stick 5218 in the camera and so long as >you're within five or six stops there's liable to be at least some kind of >image!

Brian Heller writes :

>Of course vidiots don't even need to learn how to wave a meter around -- >just point and shoot

This tread was very interesting. I learned a lot about metering I never knew or wanted to. But then, I used an Arri SR with TTL metering and truly, it was extremely accurate, except on snow shots or Nubian faces. There, I used common sense, experience and a bit of luck and was usually dead on, even on reversal.

The same with video. Just once in a while I felt that the exposure as read by the camera was wrong and tried to correct it. To tell the truth, I was right only once every three occasions.

I understand that it is very much different for features as in many cases a certain effect is desired and therefore metering of the utmost essence. I did News and docos all my life and once in a while commercials and did many second units on features. With the modern facilities now at our disposal, the endless discourse on the pro and cons of exposure, meters, black this and that escapes me. Not that everything can be fixed in post, but surely a good colorist has in many cases saved our butt. While esoteric facts are fascinating, do we thereby help and advise the new generation who reads this here CML forum in awe of our erudition?

Robert Rouveroy
The Hague, Holland

I plan to live forever. So far, so good.



....so long as you're within five or six stops there's liable to be at least some kind of image!

But Phil, you're not taking into account the fact that we really have no idea how it's going to look. This is regardless of how we expose film.

It's also totally dependant on what the soup temperature is that day etc, etc.

Using a video medium (especially HD)is the only way to know how things will really turn out.

Kent Hughes
DoP (Give or take five or six stops or so)
SoCal



>I've had a number of assistants and students accuse me of deciding >what stop I want and then waving the meter around taking different >readings until I get one I like

You mean that's not how you're supposed to do it ???

Seriously - the way I look at it, the film itself *is* the light meter -- really, that's what it DOES: respond in a rather precise (hopefully) way to given intensities of light..."the film stock knows what it's doing" -- I HOPE I know what I'm doing -- the meter is the "reality check" ready to break up a serious quarrel between me and the film.

Sam Wells



>With the modern facilities now at our disposal, the endless discourse on >the pro and cons of exposure, meters, black this and that escapes me.

Despite the astounding latitude and forgiveness of modern stocks (and the "what you see is what you've got; sorry, buddy, that's all there is" of video), it's still the case that careful metering can help the DP establish a consistency of tone that makes the colourist’s job a LOT easier. Not only that, exposures that vary from shot to shot, even if they can be pulled back to a consistent level, drag with them distortions in other tonal values: printing one shot down and another one up to obtain the same density in an all-important face will stretch the shadows and mash the highlights on one of the shots, and do the reverse in the other. While the faces may match, little else in the shots will.

You don't have to get it precisely right on location (and that colourists are a thriving breed should tell us that we don't, grin). But the closer you get it, the easier it is to obtain precisely what you were striving for later in post.

It's true that meters don't really tell you much about what the film sees. Due to differing spectral sensitivities as well as calibration and personal preferences for tonal values, the best one can do is use the meter as a reference value. Once you calibrate your mind to your stock and your meter, it provides useful, objective guidance as to where to set the T stop. But as many have mentioned, it's only a guide.

Actually, there is one meter that tells you exactly what's going on: a waveform monitor attached to a video camera. Zebras help, too; both the zebras and the WFM are looking at the image actually captured and tell you exactly what you've got. Pix monitors lie. WFMs don't.

And does anyone remember the old still fotog's rule of thumb? In daylight shooting, the correct exposure is likely to be around f/16 at a shutter speed of 1/[ASA rating of the film] second. That one's saved my sorry butt more than once. Yes, it's only approximate. But it beats not having *any* clue.

Adam "Diana Moon Glampers, here we come" Wilt
Video geek / menlo park ca usa



"BTW, is it possible to use with any success a digital camera to do that?"

I always use my digital still camera as a reassurance when shooting green screen, white limbos or large backings. Take a digital still of the green screen, load it into laptop and crank the contrast way up in Photoshop and you'll easily detect any unevenness on the screen. For exposures of TV screens I've had success using my SLR still cameras spot meter.

My 2 cents

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



Hi Brian,

I've found a second hand SEI meter and, remembering the wonderful things you wrote about it, I wasn't able to resist the temptation of buying it : I saw it as a very elegant way to start my collection...

The big problem I have now is that it's missing a couple of parts : the battery and the light bulb holders, what's left seems in very good conditions. Do you know by chance of any place were you think I can try to have it "fixed"?

Whoever else wants to know more about the SEI meter can give a look at the two following links :

http://www.shutterbug.net/features/1002sb_thesei/
http://www.huws.org.uk/

Thanks

Simone A. Rapisarda
Montreal, Canada


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