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Cinegamma & IRE

Published : 31st August 2004


Hi :

I'm a DP in Mexico and my next feature will be shoot at HD with the Sony FW900 24p. Its my first experience with the HD. I read that the contrast should not exceed 80 / 20 IRE -80 Is this so? I think this will limit a lot of shoots and since the main reason to shoot in HD is the lack of money we will not have a lot of time neither resources to limit the scene latitude.

In case of having to take a decision should I rather pay more attention to the hi lights?

Also I have read that there is a special gamma setting "cine gamma" -This on the Varicam- Which is the best setting for a nice and rich tape to film.

Any advice on the menu setting? Any special matter to take care? white and black gamma?

Thanks

Jorge Suarez C.
DP./ Operator
Mexico City



Jorge Suarez wrote:

>I read that the contrast should not exceed 80 / 20 IRE -80 Is this so?

Are you sure you want to contain your signal between 20 & 80 units ? That's what you read ? Its not clear to me exactly in the way you quoted the IRE units. Maybe they meant that's where the knee and shadow slope points begin, not the extent of your total range (which would be really limiting and counterproductive).

If you want something to look remarkably flat, with really lifted blacks, then I think I'd make it more like 10 to 90 units if you need really round numbers.

But you can use and recover highlights up into the upper 90's and shadows down into the single digits (5 points max is a good, safe place to set it...just barely lifted off the floor on the waveform if its lit & exposed properly). In fact, you can even touch 0 or go below it (it depends on your post workflow whether this will be clipped or not or whether you care if its crushed - it might look great and give you a more powerful image).

I'm a big fan of stretching the signal out as far as possible, unless for some reason the scene or shot or the look you're going for doesn't allow for it.

you are right about one thing, watch your highlights more. The shadows you'll have an easier time crushing later.

Mark Doering-Powell
LA based DP



>I read that the contrast should not exceed 80 / 20 IRE -80 Is this so?

That doesn't sound right to me. There are others here with more experience doing film outs (I assume you're going to film) but those limits are artificial, the equivalent of saying "To shoot film for TV you must never exceed a lighting ratio of 3:1".

>In case of having to take a decision should I rather pay more attention >to the hi lights?

Highlights are the big weakness of HD, just like video.

>Also I have read that there is a special gamma setting "cine gamma" - >This on the Varicam - Which is the best setting for a nice and rich tape >to film.

Cinegamma is a menu option: your two choices under the Cinegamma menu are FilmREC and VideoREC. If you are going to film you probably want FilmREC. This will yield a flat-looking image that can be stretched back to normal in post. VideoREC gives you a normal-looking picture primarily for video use.

>Any advice on the menu setting? Any special matter to take care? white >and black gamma?

Get a really good digital imaging technician to manage all this for you.

Art Adams, DP [film|hdtv|sdtv]
San Francisco Bay Area - "Silicon Valley"
http://www.artadams.net/
Local resources : http://www.artadams.net/localcrew



You might want to tryout the Cinegamma that Sony supplies with their CvpFileEditor (available on www.cinealta.com ). This creates a very nice curve in the highlights that rolls off nicely at 3-stops over middle grey and gives you about 4-4/12 stops over before clip (if you're exposing the camera at ISO 250 which is where the film-look curve is made to expose at. You're loosing detail above 3-1/2 stops, but it compresses much more gently, not a very nasty video look like simply adjusting the knee point and slope does-I've tried both and definitely prefer the film gamma curves from CvpFileEditor). Also you're getting around 4-5 stops under, for a total of 8-1/2 to just about 9 stops total (nine-stops might be stretching it a little bit, I haven't tried color- correction to see what's recoverable in the shadows, I'm just going off what my light meter and waveform monitor were saying, and at 5 stops under we were at 7.5 IRE with the black levels lifted slightly. More testing might reveal that there is indeed nine stops there).

Suffice to say, that with the film gamma curves from Sony, I've found the F900 to be a very capable camera, and not quite so video looking.

Jason Rodriguez
Post Production Artist
Virginia Beach, VA



>I read that the contrast should not exceed 80 / 20 IRE -80 Is this so?

All you need to understand that when something gets clipped (let's say, at 100 IRE) it becomes white with no detail -- and there never will be any detail there. So when you want something white and undetailed, it's OK to let it get clipped. Let's say someone momentarily shines a flashlight into the lens, flaring the lens. Obviously it's not important that you record the detail of the filament in the bulb so much as you get the bright flare (if that's what you want) and the flashlight beam actually exposes areas in the frame (if that's what you want.) Or let's say you have a hot backlight on someone's hair, creating a halo. Again, parts of the hair will get clipped once it hits 100 IRE or so but if you don't need detail in that bright halo, then it's not a problem.

Large areas of clipping tends to look ugly and unfilm-like and probably should be avoided except for an unreal effect. So if someone is wearing a white T-shirt and you want to hold some of the fabric’s texture and not let it look too hot and clipped, you might try and hold it just below 100 IRE, knowing therefore that you are recording some detail in the whites.

But otherwise, you might as well use the whole exposure range that the camera is capable, if not push it - because perfectly exposed and low-contrast photography, with no deep blacks nor pure white areas, is a little boring. A little clipping here and there in small areas is acceptable if it helps create an overall interesting image. Just know that once something is clipped, it's gone -- there is no detail there to be recovered later.

David Mullen, ASC
Los Angeles



David Mullen wrote:

>Large areas of clipping tends to look ugly and unfilm-like and probably >should be avoided except for an unreal effect.

There are several examples of this in "Bowling for Columbine" -- one has the feeling that the person shooting had not shot video before, and tended to overexpose like one would overexpose film. I'm assuming that the improved CineAlta camera has somewhat better dynamic range than the earlier one used on these scenes.

Jeff Kreines



>There are several examples of this in "Bowling for Columbine" -- one >has the feeling that the person shooting had not shot video before, and >tended to overexpose like one would overexpose film.

There is an ugly shot that starts in parking lot - which looks like 90% ire or higher - nearly totally blown out, and they go into the store (WalMart?) where the exposure is correct. They must have started inside, set the exposure, then gone out and pretended like they were just beginning. (Or maybe they zoomed into the store windows and set exposure).

I'm not sure of the purpose of that - nor why they didn't just put it on automatic - it's not like we would be jarred by the effect of the camera adjust - it is a documentary after all. More or less.

I'm assuming...

>that the improved CineAlta camera has somewhat better dynamic >range than the earlier one used on these scenes.

Yes, it does.

Dale Launer
Writer / Filmmaker
Santa Monica



>All you need to understand that when something gets clipped (let's say, >at 100 IRE) it becomes white with no detail -- and there never will be >any detail there. So when you want something white and undetailed, it's >OK to let it get clipped.

Also keep in mind that other things can happen in these areas, for example, if you do have a clipped area and you do a global color correction such as darkening the picture, the clipped area can become a slightly gray highlight depending on the amount of correction. Also, grossly clipped areas can solarize, and even invert in color.

Very difficult to fix in post.

Dave Stump ASC
VFX Supervisor/DP
LA, Calif.



>one has the feeling that the person shooting had not shot video before, >and tended to overexpose like one would overexpose film.

I'm not sure what list this belongs on, I'm tempted to say ALL of them.

Is it just me or has this whole notion of "overexposure" broken loose from reality ? I'm starting to believe people are out there are "overexposing" film negatives NOT in regard to any real notion of photochemistry, but because they've read on the internet that Real DP's "overexpose the film"

No small wonder that this lemmingism might extend to HD shooting.

(As far as I'm concerned if I rate a box rated EI 250 at say 160, am I really overexposing ? Not exactly, I'm exposing "normally" according to purpose).

Sam Wells



Sam Wells wrote :

> Real DP's "overexpose the film

Tell that to the Godfather-era Gordon Willis, who underexposed film so that no one could print it to look differently than he wanted (or at least limited the damage that they could do).

Jeff "he wuz robbed by the Academy multiple times" Kreines



IRE readings are not an absolute measurement and should be taken as rough guidelines only in my opinion. On an HD feature I shot I had a situation with a completely white room with white, shiny props and African American actors. After setting exposure, looking at the monitor, tweaking the knee function severely and liking the image, I looked at the waveform and saw in horror that the values went up to 112 IRE. With these knee settings I would get details to about 108IRE on the monitor and the rest would go white with no detail, in portions of the frame where this was visually fine with me.

It worked for the shots and the mood I was after. Although I was a little concerned about this, I stuck with my instinct and didn't run into any problems through post with this approach.

My 2cents

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



Jason wrote :

>You might want to tryout the Cinegamma that Sony supplies with their >CvpFileEditor (available on www.cinealta.com). This creates a very nice >curve

Thanks everybody for the advices.

I'm trying to download the gamma builder from the Cvpfileeditor but I can not get through. Does it work with the F900 first model? that's the one I'm using.

Thanks

Jorge Suarez
DP/Operator
Mexico



Hi Jorge :

In order to use the film gamma you need the new version of F-900 or the old one update v.3. You can not use film gamma in older F-900.

To download film gamma you need CVP file editor v.2 It not possible with version 1.

You can found information of film gamma in www.alfonsoparra.com An article from high definition magazine.

Best regards

Alfonso Parra (a.e.c.)



>Is it just me or has this whole notion of "overexposure" broken loose >from reality ? I'm starting to believe people are out there are >"overexposing" film negatives NOT in regard to any real notion of >photochemistry, but because they've read on the internet that Real DP's >"overexpose the film"

There's little doubt that's a part of it.

The other part I have experienced is DP's who resent having to shoot electronically when they would much rather shoot film, and go out of their way to play on the electronic medium's weaknesses to justify their endless whining on set about video (HD or SD).

Setting an exterior window light (so the outside looks blown out) at ten stops over instead of what will actually work to reveal some detail in the blowing white curtains is an example which I've witnessed several times, along with the DP complaining to the director/producer/client that this is a clear example of why shooting on video in any form is a waste of time and effort.

Suggestions to lower the value of the exterior light are either ignored or attacked.

It makes me wonder why they took the job in the first place.

>IRE readings are not an absolute measurement and should be taken >as rough guidelines only in my opinion.

In fact, IRE readings are an absolute measurement of the luminance component of the image being viewed. You are certainly free to ignore them, but that doesn't make them any less correct.

In that regard, they are not much different from a spot meter reading.

Bob Kertesz
BlueScreen LLC
http://www.bluescreen.com



Bob Kertesz wrote:

>Setting an exterior window light (so the outside looks blown out) at ten >stops over instead of what will actually work ...

On stage, I have to agree with that to some degree. However, on location, the ability to handle hot highlights, particularly when the light through some of those windows is uncontrollable (i.e., a dome in a church that cannot be tented) is one of the unassailable advantages of film origination.

Mike Most
VFX Supervisor
IATSE Local 600
Los Angeles



Bob Kertesz writes :

>The other part I have experienced is DP's who resent having to shoot >electronically when they would much rather shoot film, and go out of >their way to play on the electronic medium's weaknesses to justify their >endless whining on set about video (HD or SD).

I'm shocked...shocked to hear this

Brian Heller
IA 600 DP



Bob Kertesz writes :

>Setting an exterior window light (so the outside looks blown out) at ten >stops over

This anecdote is no doubt an extreme example, but there's some truth behind it. As someone who slaves over hot Cineon files every day, I can tell you that film captures an amazing amount of extended highlight information, and that the ability to pass those brighter-than-white values through into the final negative is a critical part of making a good-looking print. If a DP is going to err, I would much rather they erred on the side of over-exposure with color negative, and under-exposure with reversal or digital. Yes, declining film response starts crushing shoulder scenes, but within limits they can be pulled it into the straight-line portion. Which is usually preferable to pulling a scene up off the toe/noise floor, i.e. having to heavily degrain an underexposed scene. Extreme degraining works, if you don't mind soft, plasticky scenes with sizzling edges.

Again, IMHO digital acquisition won't really be the mainstream until we're devoting about 30% of the brightness scale to over-whites. Today's RAW file capture in my experience only gives you a very crushed and banded 5%.

Tim Sassoon
Sassoon Film Design



>the DP complaining to the director/producer/client that this is a clear >example of why shooting on video in any form is a waste of time and >effort. Suggestions to lower the value of the exterior light are either >ignored or attacked.

Wow. Talk about unprofessional... what a bunch of whiners.

It's only a matter of time before film goes away, unless it continues to improve dramatically every couple of years. I love film, but I also see many people jumping at HD because it's "almost as good" and often quite a bit cheaper. (The cheaper part is the key, obviously.)

As chips improve more and more projects will be shot on HD. One could almost say there's a mad rush to provide an alternative to film, what with Dalsa and Arri rushing to catch up and surpass Sony, Thomson and Panasonic.

Those of us who embrace HiDef will ultimately win out over the film Luddites. Yes, film is marvellous; but I'm guessing that in five years HiDef will have made even greater strides against film. Hopefully the forthcoming Vision3 stocks will jump light years ahead of electronic acquisition once again.

I regularly hear stories about film DP´s having to shoot their first HiDef job and being completely clueless. Most, though, see the reality of having to learn the format in order to stay employable. I'm just surprised that there seem to be so many DP´s out there who don't know the basics of how video works. (I guess I'm a bit jealous.)

Art Adams, DP [film|hdtv|sdtv]
San Francisco Bay Area - "Silicon Valley"



No, you have to have the "/3" version of the camera.

Jason Rodriguez
Post Production Artist
Virginia Beach, VA



Tim Sassoon wrote :

>Today's RAW file capture in my experience only gives you a very >crushed and banded 5%.

From which cameras? The Viper?

Do you think the Genesis has improved anything in this area?

Jason Rodriguez
Post Production Artist
Virginia Beach, VA



Jason Rodriguez writes:

>From which cameras? The Viper?

A big generalization, including everything from Viper to digital stills. I reserve the right to be sort-of accurate for dramatic effect.

>Do you think the Genesis has improved anything in this area?

Not noticeably. We need a big, big jump in highlight detail. I'm not a film Luddite, but let's be realistic about what the real capabilities are now, and where they need to be for digital to truly surpass film, which I absolutely believe it can.

Tim Sassoon
Sassoon Film Design
(gonna hold on to my Arri 35 until it's worthless, though)



> I'm not a film Luddite...

Why is it that people who prefer the sound of vinyl over CDs are called audiophiles, serious collectors, real music lovers, etc. but people who prefer the look of film over digital are called Luddites?

(OK, I'm due on set shortly and didn't get much sleep and am cranky, but I still think it's a valid point...)

Jessica Gallant
Los Angeles based Director of Photography
West Coast Systems Administrator, Cinematography Mailing List
http://www.cinematography.net



Jessica Gallant writes:

>Why is it that people who prefer the sound of vinyl over CDs are called >audiophiles, serious collectors, real music lovers, etc. but people who >prefer the look of film over digital are called Luddites?

This may be because vinyl recordings are no longer produced.

If the day comes when film is no longer manufactured, and if, in order to insure yourself a steady supply of spare parts, you are hoarding the carcasses of old projectors in your basement, you'll be able to call yourself a serious collector and a real movie lover

Living in an abandoned movie theatre would also help.

Brian "now going to chat" Heller
IA 600 DP



Art Adams writes :

>I'm just surprised that there seem to be so many DP´s out there who >don't know the basics of how video works.

Brace yourself, Art. Motorola is about to put video cameras in cell phones.

It may help to put your mind at ease about ignorant DP's to think of all the people out there on the highways driving their cars at 80+mph who don't have the slightest idea of how their cars work either.

BTW, I haven't heard any stories of any deaths resulting from bad video. Although there is a rumour about a video engineer who ran screaming from the control room of America's Funniest Videos and hasn't been heard from since.

Brian "You talkin' to me?" Heller
IA 600 DP



Brian,

>This may be because vinyl recordings are no longer produced.

Guess you haven't been to a record store lately? Vinyl is back and hot. Film is not going to go away nor will it for decades. HD is getting better but it's not a perfect substitute for film.

Another tool in the bag of tricks.

Remember still photographers are still using all sorts of processes that date from the 1800s.

The echoes of technology are very long indeed.

Robert Goodman
Author/Photographer
Philadelphia, PA



>Brace yourself, Art. Motorola is about to put video cameras in cell >phones.

Will give fresh meaning to the when someone says an actor
"phoned in their performance".

Dale Launer
Writer / Filmmaker
Santa Monica



Robert, you wrote:

>Guess you haven't been to a record store lately?

You're right about that. Not since Skippy White's closed anyway.

>Vinyl is back and hot.

So several others have told me as well. Vinyl is also required by DJ's to do their scratch thing. You'd think I would know that since I've worked on a bunch of Rap videos

>Film is not going to go away nor will it for decades. HD is getting better >but it's not a perfect substitute for film. Another tool in the bag of tricks.

I agree with that sentiment. I was just tweaking Jessica's lament about being called a Luddite.

>Remember still photographers are still using all sorts of processes that >date from the 1800s.

>The echoes of technology are very long indeed.


That's absolutely true for still photography which is essentially a one man operation, but I'm not so sure that the incredible precise manufacturing techniques necessary to produce motion picture film that will properly run through a modern MP camera is going to be easily picked up by future movie makers.

Just so you know, I'm a card carrying member of the Photographic Historical Society of New England. And I have no doubt that at some future date enthusiasts will be making their own motion picture film. However, I also have no doubt that the end of film as a practical production medium will be brought about when it is no longer economically viable for Kodak or Fuji to produce film.

Also I couldn't agree with you more about HD's not being a substitute for film.

Brian Heller



>Remember still photographers are still using all sorts of processes that >date from the 1800s...The echoes of technology are very long indeed.

Somehow this seems relevant even on Hd list: to anyone in LA area, go see the exhibit at the Getty called "Photographers of Genius". I think it ends July 25th, so hurry. Get there by 10:30am and you can get $5 parking without a reservation.

A remarkable representation of the history of photography, and I had no idea the mastery of soft light, painterly and impressionistic portraits done back in the late 1800's. Really great stuff.

And the absurd level of detail in these old prints, the level of technique and skill in capturing and printing them. I realize many are large format and clunky until the Graflex (still big by today's "elf" standards) but that didn't stop any of the pioneering photographers in capturing some great images.

Long echoes indeed, and having as much or more to do with the artist than the technology.

Mark Doering-Powell
LA based DP



Brian Heller writes :

>Also I couldn't agree with you more about HD's not being a substitute >for film.

It's only a substitute when you put DP's in a screening room and they can't tell the difference....or one is better than the other.

Nick Hoffman



Jason Rodriguez wrote :

>No, you have to have the "/3" version of the camera.

How can I know if the f/900 has that version.

Also Can anybody recommend a place to make the tape to film in Austin Area?

Regards

Jorge Suarez



Jorge Suarez wrote:

>Also Can anybody recommend a place to make the tape to film >in >Austin Area?

Isn't DVfilm in Austin? ( www.dvfilm.com )

I've never used them before, (heck, I've never done a film-out of video before), so I'm not sure how good they are, but you might want to check them out.

Jason Rodriguez
Post Production Artist
Virginia Beach, VA