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Techniques for Independent Production
The challenges of creating Digital Cinema and other narrative forms.

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Old July 19th, 2003, 03:28 AM   #1
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after careful study i have the answer!

ive been trying to figure out what the differences are in film and video, you should all know the production qualities. im going to first assume you know how to do properly lighting and staging and camera work, and that you know how to use your camera as well as DOF and the motion issues (frame rate, motion blur, shutter speed, etc).

secondly, im going to assume you know that the contrast lattitude of digital video on average is about 4 stops versus around 9 for film.

so.....after much experimenting and deep thought and study of film frames and digital frames i have found the closest thing to an answer.

CURVES.

the article posted on this site has a very vague and in my opinion incorrect description of how to use curves (in after effects) when describing the creation of a 'film' look, they might as well have just increased the contrast.

i have determined that you can give digital video something equivalent to a 16 or super16 quality look in post, at least in terms of latitude....digital is its own animal, not film for sure, but not without hope.

by increasing (or extending) the APPEARANCE of more values in the highlights and more values in the low mids and less in the darks you can fool the human eye into seeing more lattitude then is there.
it seems silly and its difficult to explain and must be tailored to each scene and a desired look. but the key is to use curves and leave the mid tones alone, slope the highlights downward (towards grey) subtly and the darks towards black.

also, this only works well if you dont have large areas of blow-out or deep shadows, a neutral image is preffered as it gives you creative freedom with your images look.

i am working on a guide with specific examples for a film look, once its done ill post a link to the guide.

of course color grading and color correction are also critical to the process as well....but thats just because modern film uses it all over the place....so im assuming you want a contemporary look as well.
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Old July 19th, 2003, 03:37 AM   #2
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Hmmm, so your basically saying to DECRASE the contrast? It doesn't look right.

If you have a well composed shot, you shouldn't have to deal with any dynamic range problems.

I did what you described (basically decreased the contrast) and this is what I got, along with "my method" and the original. It's a framegrab from some video I shot yesterday doing tests for that extra extra wide cinema look.

http://img.villagephotos.com/p/2003-...5/Image475.jpg

Right, decreasing the contrast brings out more detail, but it also gives you a ugly grey overcast. I'd rather loose some detail and get nice colors. :D
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Old July 19th, 2003, 05:24 AM   #3
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yah, so thats not quite it.....it'll be clear what i mean when i post some pics (of the curve), the key is only lowering the contrast at the very peak of the brights and subtle slopes....your method is similar to what i get and quite good as well....as far as i can tell at the small size....if your method works you dont need to listen to me anyway, heh.

....heres my sample using my method on the middle picture (untouched).

http://www.letterstoyou.com/sample.jpg

of course what i said about highlights doesnt really apply here because the picture is so small that the detail isnt really there to tweak, but you can see how all the other levels are adjusted as well.
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Old July 19th, 2003, 08:36 AM   #4
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Joe,

You're a genius and don't know it. What you've described is a relatively recent method of High Dynamic Range (HDR) imaging used in computer graphics and, recently, some computer games. Essentially, they're taking the true range of available light and moving it into the range of the viewed medium.

For example, a scene with bright sun and deep shadow in a range from 1 to 100 to be displayed on a medium with a range of 1 to 10. Calculate what percentage each brightness value is and fit it into the smaller range. This way very bright and very dark areas look the same though you have adjusted their range.

This is the same thing someone in a darkroom does with a film negative. The phrase is "expose for the shadow, develop for the highlights". This way the photographer is sure to capture all the image information on the negative. He can then pull detail out of areas by dodging and burning.

Film though is an analog medium. You are correct about curves. Everything on film is recorded in an analog curve of light. Digital is not a smooth curve due to the digital recording method. While this gives digital its "sharper looking" appearance, the reality is it loses information between color and light levels that film captures. An edge between a solid black and solid white area may be sharper than film because the digital camera can't record all the light between the two ranges. But that is also what causes stairstepping.
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Old July 19th, 2003, 03:10 PM   #5
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<< This is the same thing someone in a darkroom does with a film negative. The phrase is "expose for the shadow, develop for the highlights". >>

Yup, and the trick for good looking video is "expose for the highlights" (similar to the practice one would follow for shooting reversal film). I routinely underexpose exteriors by anywhere from 1 to 2.5 stops if they feature bright sunlight and contrast. You can always expand the range back in post. The important thing is to capture detail in the highlights; what your camera tells you is the correct exposure usually results in washed-out faces and blotchy skies.

Adjusting the gamma curve has long been a core element in filmlook emulation.
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Old July 19th, 2003, 03:44 PM   #6
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Charles- I have seen photographers using a light meter, and something similar used in film. What do you use?
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Old July 19th, 2003, 05:41 PM   #7
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From a layman's (newbie) perspective - if Charles underexposed exterior shots (making sure highlighted areas have detail), then could I apply that to the example below?

If I am shooting a stage play (which I frequently do) where faces are sometimes washed out by bright lights, I should shoot manual mode, slightly UNDER-exposed so that I can see the detail in their faces. Then in post, tweak the clip so that the appropriate color/contrast is shown. And theoretically I'll have a finished video with a good, sharp image with good detail in their faces.

Did I explain that right?

Thanks in advance. This is very interesting for me!
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Old July 20th, 2003, 05:49 AM   #8
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Keith:

For film work I do use meters: a Spectra incident meter and a Minolta spot meter.

However, for video work I usually light to the monitor and a waveform monitor if available. The exception would be if I was pre-lighting a set without the camera present, in which case I would use a meter to make sure the light level is correct.

Mark:

That sounds like a good plan. A while back I shot a play that a close friend had written and produced, probably the first time in 10 years or so I'd done that sort of shooting. I had my XL1 with the manual lens, and we had another camera with a GL1. I had hoped to work with the tech crew to balance out the light levels for the video, but it wasn't going to happen, and there were several scenes that were very high contrast (spotlights and pools of light). During the performance I was constantly riding the manual iris to net the best exposure, which as you indicated was slightly under-exposed depending on the scene. In those high contrast scenes I went tight on the characters within the hot areas and rode the stop down to an appropriate level. The other shooter went with auto iris.

The result was that his camera was constantly too hot, and the actors in the spotlights or hot pools were blown out, sometimes beyond recognition. On my camera, they rendered nicely. During the editing phase, the producer constantly urged me to try to bring back some detail into the blown-out faces from the GL1, and of course I had to tell him that it wasn't possible.

Sometimes I ended up with a slightly dark image overall from the XL1, with the actors out of the spotlight coming in a bit muddy, but using the color correction in FCP3 I was always able to punch up the midtones to a satisfactory level.

Hope this answers the question!

By the way, the underexposure technique for exteriors was well used in "28 Days Later" (one of the articles I read described this process exactly).
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Old July 20th, 2003, 01:01 PM   #9
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joe, please do post some specific techniques to use in After Effects when you get a chance. I like the results you are getting. I find that the tutorial on this site results in footage that is overly saturated. It's definitley an improvment, but I'd like to try out your method and I'm a bit confused on which curves to manipulate in which way. When you get a chance, I'm sure we'd all appreciate you writing out a mini-tutorial with some screenshots of those color curves. thanks!
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Old July 20th, 2003, 04:31 PM   #10
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Thanks for that info, Charles. I shoot all of the stage plays for the City Arts and the Playwright's Forum I belong to and a good percentage of the finished video looks good (GL1), but when actors move around on the stage (ie: separate to either end) and I have to have a very wide shot, then that's when their faces are blown out.

If I zoom in tight, I can get good detail in the brightest conditions, but then the other 95% of the stage is unseen - which is not an optimal condition shooting theatre!

I'm going to try the manual way on AUG 9, as I'm shooting a doc that culminates in three short plays in the evening (three playwrights, three directors, one music composer and twelve actors write, rehearse and perform three short plays, beginning at 10:00 a.m. with live performances at 8:00 p.m.).

One question though - I don't suppose a 2x or 4x Nuetral Density filter would do the same thing would it? Or would it just under-expose everything?

Thanks again.
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Old July 21st, 2003, 06:22 PM   #11
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In another thread somewhere I came across this tutorial which seems to cover similar ground

http://www.dvinfo.net/articles/filmlook/broadway2.php

and shows curves etc -- it's all about replicating the density curve of film isn't it?

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Old July 22nd, 2003, 03:42 AM   #12
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that is the tutorial listed on this site that i find does not properly explain or (necesarily) understand the use of curves to as you said properly emulate the curve density of film

since this is the big example ive made a few examples myself of different looks using different, curves, since the look you want will affect how you adjust the curves and then the color grading all are unique. i should have my guide finished soon and then ill put it up, with specific examples on how to understand the original picture, how to make that emulate the look of film properly and then how to distort the curves further to create your own look that is still film-like. the main thing with curves is that the curves have to slope subtly to be believable.

the top left is the original and the top right is the post they made (too saturated for my taste but otherwise good) and then 4 different looks i created below using curves and then color balance.

http://www.letterstoyou.com/curves00.jpg
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Old July 22nd, 2003, 05:40 AM   #13
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Mark, to answer your question (sorry Joe, we seem to have two different threads going at once in here), ND filters won't help in this situation as you guessed. The problem is too much contrast within typical stage lighting which can really only be addressed by altering the lighting itself (or the gamma curve of the camera--to make this more relative to the subject of the thread!!--which can't be done with the GL2).
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Old July 22nd, 2003, 05:49 AM   #14
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By sloping the colour curves, that's almost the same as adjusting the contrast from what I see.

Why not just adjust the contrast then?
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Old July 22nd, 2003, 11:15 AM   #15
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Joe, slightly off topic but I would like to add that there is a very good, lengthy film look article on http://www.dv.com
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