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Vector and Wave Form monitors


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#1 George Ebersole

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Posted 30 May 2008 - 12:11 AM

I'm reading Paul Wheeler's highly informative book on Digital Cinematography, and he states that he doesn't use a waveform monitor on his shoots.

For film that's a no brainer, but for video (at least when I was working a lot back in the mid 90s) that was begging for trouble. I think his reason is that the direct feed from the camera, as long as it is directly from the camera and not looped or slaved to another device, is adequate to judge detail and color. I found this really shocking, but I've been out of the loop for a few years.

That seems a little iffy to me, but that's my video background talking. I simply don't know much about digital cameras shooting 24p

Do a lot of you folks use waveform monitors and vector scopes on a digital shoot that you know is going to get transferred to film? Or do you invest in the extra equipment to make sure you got your colors right?

I'm really curious about this.
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#2 Satsuki Murashige

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Posted 30 May 2008 - 12:22 AM

Hmm, well maybe that's the case if you shoot for RAW output, like with the RED, F23, Viper, etc. I work on my first RED shoot this Sunday, so I'll ask the DP how he feels about the issue. I can tell you that with HD shoots on F900R, Varicam, HPX500 type cameras where the image needs to be painted in-camera by a tech, we most certainly use waveform and vectorscopes on set to judge exposure and chroma. Not doing so seems rather irresponsible, like exposing film without a light meter (unless you're Henri Alekan or Douglas Slocumbe that is!).
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#3 Timo Klages

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Posted 30 May 2008 - 02:48 AM

Hmm, well maybe that's the case if you shoot for RAW output, like with the RED, F23, Viper, etc. I work on my first RED shoot this Sunday, so I'll ask the DP how he feels about the issue. I can tell you that with HD shoots on F900R, Varicam, HPX500 type cameras where the image needs to be painted in-camera by a tech, we most certainly use waveform and vectorscopes on set to judge exposure and chroma. Not doing so seems rather irresponsible, like exposing film without a light meter (unless you're Henri Alekan or Douglas Slocumbe that is!).


well, i have only been working with the Arri D20 a few times now but i was more than glad to have an Astro HD Waveform Monitor with me. Of course measuring the light to see what stop you should use is a good thing but i am more comfortable with a wave form and it really shows me, what the camera is recording.
but i have a more technical / broadcast background as well ...

greets,
timo
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#4 Satsuki Murashige

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Posted 30 May 2008 - 03:12 AM

Of course measuring the light to see what stop you should use is a good thing but i am more comfortable with a wave form and it really shows me, what the camera is recording.

Just for clarity, I'm not suggesting that people use light meters with video - I'm saying that a waveform in the video world is the equivalent tool to a light meter in the film world. If you wouldn't shoot film without a meter, you probably shouldn't be shooting video without a waveform unless there's a good reason not to.
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#5 Stephen Price

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Posted 30 May 2008 - 03:38 AM

I have also read his books, admittedly they are very good and informative, but the impression i got from when i read that he does not use waveforms is that he is suggesting he is so good he doesn't need to rely on this electronic tool.
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#6 Jonathan Bowerbank

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Posted 30 May 2008 - 04:18 AM

I worked with a DP once who seemed to be very confused in regards to the usefulness of a waveform, either that or we just didn't have time to discuss his opinion further. But he claimed a lot of people he's worked with who adhere to the waveform monitor usually produce very flat and uninteresting work because they're overly concerned with blown out portions of the frame.

I do understand what he's saying in regards to how concerned some people may get about the blow out issue though. A frame is usually more interesting if it contains a full range of underexposure to overexposure, so I'm generally perfectly fine if there's an unimportant object in the frame that's clipping a bit. But with the inexperienced shooter who's just finishing his first "How to shoot DV" book, those zebras in the viewfinder/LCD display are like fiery darts in their eyes and sometimes causes for panic.

But as long as my waveform is showing me that the whites are clipping at 100+ and not something like 85, then it's all good in my hood.
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#7 Stephen Murphy

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Posted 30 May 2008 - 04:25 AM

I rarely ever use a waveform!
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#8 Walter Graff

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Posted 30 May 2008 - 06:37 AM

You don't have to shoot with a waveform but somewhere in the process a waveform must be used. A video signal isn't some abstract signal you can bend and twist any way you want. You may like 120% white, or blacks at minus 20 when you shoot, or reds so rich that they bloom, but when that final project is outputted, it must fit into the standard that is HD digital. And many times it is automatically done for you in your final output, but many don't know this. But whether you are going to tape, DVD, or anything else, colors must be in spec as must all video signals. And even if you shoot them way out of spec, proc amps will most always bring them back into spec so not knowing this and shooting for some look may end up yielding a look you didn't expect or want. I am working on a video to teach this to people as many untrained video people think you can just add as much color as you want to a signal or make pictures as dark or as bright as needed. You can but if it is out of spec, it affects how the viewer sees it (sometimes not in a good way) and sometimes adversely affects the screen you see it on to the point of creating unwatchable pictures. Knowing how a waveform/vectorscope works is key to understanding how to make great looking pictures. Those that do not know how to use them are lacking a key part of the knowledge of video and are often the ones who complain that video never looks great. You can play all you want with internal controls on a camera, but if you have no way of measuring your results and where those results fall inside the spec of a video signal, you are driving a car with no speedometer, no mirrors and nothing but second gear.

I have not read Mr. Wheelers book, but a statement such as this shows little understanding of video and more ignorace than education.
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#9 John Holland

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Posted 30 May 2008 - 06:42 AM

The only times i have made any form of video picture look good is by not using or ignoring what the waveform was showing and getting some vision engineer upset ,which is always good fun.
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#10 Phil Rhodes

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Posted 30 May 2008 - 06:45 AM

Not a - gulp - BBC vision engineer? Aaugh!

I find waveforms are useful for maintaining consistency of exposure - or more properly consistency of underexposure, on video. I habitually, as I suspect is standard practice, enormously underexpose video, and it's easily overdone.

P
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#11 John Holland

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Posted 30 May 2008 - 06:49 AM

Yep Phil. a BBC vision engineer they are the best to bait .
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#12 Jonathan Bowerbank

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Posted 30 May 2008 - 02:27 PM

Yep Phil. a BBC vision engineer they are the best to bait .


Ha ha, I was working with the aforementioned DP on a BBC project. And he was given 4 pages of specifics from a BBC video engineer instructing how to get the "film look" from a Varicam. He flipped through it for a couple seconds, tossed it aside then just told me to do what I felt was best.
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#13 Satsuki Murashige

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Posted 31 May 2008 - 12:14 AM

The only times i have made any form of video picture look good is by not using or ignoring what the waveform was showing and getting some vision engineer upset ,which is always good fun.

That's funny, I asked my DP something along these lines today while he was lighting a shot. I wanted to know where on the IRE scale he generally liked to place skin tones since he judges exposure almost entirely from the waveform. His reply: "anywhere on the scale that I want for the look that I'm going for. If I want a high key look with bright flesh tones like on our last job together (a cheesy corporate Intel ad), I'll set them around 85-90 IRE. For the dark look we're going for today, I want to live around the 50 IRE range."

This really got me thinking that exposing from the waveform in this way is functionally the exact same thing as taking spot meter readings of various tonalities and placing them on the film negative's characteristic curve (as you would with the Zone System). If you want the look of a skin tone underexposed two stops on film, wouldn't you use a light meter to make sure you had the correct amount of light to achieve this effect? Well, substitute the light meter for a waveform and you will be able to make the same determination of exposure while shooting video. I imagine there are a lot of ultra-orthodox techs out there who would have a problem working this way, but the DP is the one who is supposed to make these exposure decisions, not the tech. So if the footage looks uninteresting, then as the DP the final responsibility for shooting bland footage must rest with you (I'm not attacking you personally John, I'm only speaking generally). If you can light well, then you can make any format look good, be it film, video, or pixelvision. Anyway, that's just my opinion.
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#14 George Ebersole

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Posted 31 May 2008 - 12:32 AM

Thanks everyone, for the very informative replies.

Digital (HD), according to Wheeler, is supposed to alleviate the problem with color correction and detail level that a waveform does for a traditional studio camera, but I'm not entirely sold. He goes into the history of the technology of how and why colors were so skewed (the whole reason why waveforms were needed in the first place), but even though it's digital, it's still a video signal.

I didn't get the sense that Wheeler thought he was so good he didn't need the extra equipment. I got the sense that he had real faith in digital technology to overcome the problem of color bleed and video noise. I'm a babe in the woods, so I really have no clue, but like hearing all of your opinions.

Again, as I gear myself up for going back into film and video I'm learning about how some things have changed.

Thanks again.
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#15 Tim O'Connor

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Posted 31 May 2008 - 12:34 AM

I worked with a DP once who seemed to be very confused in regards to the usefulness of a waveform, either that or we just didn't have time to discuss his opinion further. But he claimed a lot of people he's worked with who adhere to the waveform monitor usually produce very flat and uninteresting work because they're overly concerned with blown out portions of the frame.

I do understand what he's saying in regards to how concerned some people may get about the blow out issue though. A frame is usually more interesting if it contains a full range of underexposure to overexposure, so I'm generally perfectly fine if there's an unimportant object in the frame that's clipping a bit. But with the inexperienced shooter who's just finishing his first "How to shoot DV" book, those zebras in the viewfinder/LCD display are like fiery darts in their eyes and sometimes causes for panic.

But as long as my waveform is showing me that the whites are clipping at 100+ and not something like 85, then it's all good in my hood.


I've used both for a long time, although not on every shoot because sometimes I simply don't have them.

I've noticed that since the digital age, many people say that they want their whites to clip at 105 IREs and they use the zebras to measure this (in those cameras that will allow that setting.) Maybe I've just had it ingrained in me, but I'm hesitant to do that, especially since I remember the days when a blown out sky would sometimes cause audio noise ( a distinct, faint buzz) every time those shots with blown out areas came up.

I learned how to use waveform monitors/vectorscopes working at television studios and on commercial sets by talking to the engineers. I used to look for a good book on the subject but except for occasional short articles and the manuals that came with the equipment which do presume a certain amount of
knowledge on the part of the reader, I've never found a good text. Has anybody?
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#16 Satsuki Murashige

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Posted 31 May 2008 - 12:38 AM

I imagine there are a lot of ultra-orthodox techs out there who would have a problem working this way, but the DP is the one who is supposed to make these exposure decisions, not the tech.

Now that I think about it, this situation is very similar to the days of Technicolor and the company consultants would would tell the DPs and art directors not to use certain colors, not to under/overexpose,not to use lens diffusion, not to use smoke, etc. etc. A lot of Technicolor films that followed those guidelines are pretty bland looking too. Of course, some courageous and artistic cinematographers, art directors, and directors broke those rules and managed to produce some of the great cinematic images in film history. But they had to know what they were doing in order to do so. They're artistry was a result of their gift for visualizing textures of light and color, and also their technological prowess to realize those visions.
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#17 Walter Graff

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Posted 31 May 2008 - 01:41 AM

You can expose faces anywhere you want. Or the sky anywhere you want. Or crush blacks as much as you want. But somewhere in the chain those signals need to be put in spec. Spec is basically the highs and the lows, and color. If you decide you like blue and arbitrarily decide to use a blue that is so pumped up as to be nowhere to be seen on a vectorscope, your shot is going to be put into spec and all you thought you had or wanted as a DP is going to be lost in the end form the way you envisioned it. No ifs ends or buts about that. So say you decide to overexpose your faces because you like the look. And in doing so you push the gammas high, and over expose the highlights to the point of pushing the picture well off the chart. Regardless of how you wanted it to look when you shot it, it's going to be adjusted so it fits properly in a proper TV picture specs. And that means regardless of what you thought it was going to look like, it's not going to. Knowledge comes not necessarily from reading a waveform with every shot but understanding what it translates to on a waveform so that when you light, you know what the limits are and know what the subtleties will do, so that you understand what is between 0 and 100 and what it represents. That's why it's critical to know how to read one and to know how it translates to the voltage on a scope. It's the equivalent of understanding how a film stock reacts. Its no different than when you get good enough with light meter that you can call out the stop you want just with film by simply looking at a shot by eye. The light meter was the guide that gave you an understanding of the range you had to work with and what they translate to on film.

An engineer is not a DP, he's a spec man. He knows how to keep signals where they belong or put them where you want them as long as it is in the proper spec. To ignore an engineer or have a caviler attitude about an engineer or network standerds shows a real lack of understanding of the art and a real loss of knowledge about the possibilities of the format in my opinion.
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#18 Walter Graff

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Posted 31 May 2008 - 02:05 AM

The difference between analog signals and digital is like the difference between sending water down two different pipes. The water remains the same in the end but how you got it there was different. In the end digital has a more exact tolerance (eg: difference between 7ire ed and 0ire) but the methods and results are the same, based on a standard and a tolerance to be in that standard. Waveforms didn't go the way of the wastebasket, rather more people got involved in video that were not properly taught about the tools and methods that make for better pictures. In years past you had people that knew how to get good pictures and knew the limits and worked together to make those pictures great. Now you have a bunch of people that think it is their right to play with the controls of a camera (control labeled 'engineering settings') as if anything they adjust, regardless of whether they understand it is perfectly acceptable and no one has any right to tell them what they are doing might not be the best thing to do, all because they are DPs and DPs are in charge of how a picture looks... Cowboys who always learn the hard way.
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#19 George Ebersole

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Posted 31 May 2008 - 03:58 AM

I remember a DP I used to work with every now and then, Mickey Freeman, was pretty skilled when it came to handling an Arri IIIBL, but rarely, if ever, shot any video (or so I recall) But when he did shoot video he always referred to the video tech, the person running the deck, for info on color. At least I think I remember him sitting on top of a Chapman at what used to be Stage 39 on a Betacam shoot. Then again, when I was working film DPs and videographers were usually two different breeds of people entirely. It sounds like that's not so much the case anymore.

I guess if you're a DP you need to be a little video-tech savvy these days.
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#20 Walter Graff

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Posted 31 May 2008 - 06:16 AM

I remember twenty years ago when I worked for some pretty big names in film, guys who hired me because of my knowledge of video and background in film, to be a pair of eyes over their shoulders as they shot video because they knew nothing about video, how to expose it, how to adjust it, etc. Sort of like what happens when you take an English only speaking person and drop them in the middle of Japan. But they learned a lot, and I learned a lot about how film only people perceived video. Flash forward twenty years. Manufactures are using catch phrases that make video more like film from the get go, HD is the new "Just like film" craze. The internet is now a resource that makes anyone a DP, and anyone an expert at video, just by looking up what settings are 'best' for a camera on a web page after a Google search. And people now know how to access the engineering menus of a camera, and even more, apply the knowledge of film terms and everything else between the shoulder and toe to video with the ignorant thought that it's like film, just with less dynamic range. Oh, yea, and DPs are the people that have total control over a picture so the hell with any concern for video standards, etc. I'm the DP, and just like with film, I can adjust a camera with the false notion that like film, my ignorance to the engineering settings in a video camera matter little. But unlike twenty years ago when a film person knew little about film vs video and thought it okay to expose highlights at 20 units because it looked good on a monitor and 'like' film, now I'll expose the same way, but be able to make all sorts of adjustments to the camera and think it's all okay, everyone knows you can adjust a camera as you please, ignore people who are trained to make proper video adjustments, never consider that cameras need to be shaded for a baseline and accuracy before shooting anything, just turn them on and go, not need a waveform or vector, mostly because "I really don't know much about what they do and I've gotten along fine without any more knowledge than a film DP needs to have to make good pictures" when working with video. Bottom line, same problem people had twenty years ago, but now with a different attitude and the internet to tell them it's all okay. :)
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