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Stunning Good Looks

by Art Adams

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Monday, March 17, 2008

RED ONE Build 14 Latitude Tests

Wherein I investigate whether the RED ONE’s 5000k chip loses effective latitude in tungsten-lit environments

RED ONE Build 14 Latitude Tests

My goal was to see if RED’s 5000k chip is limited in exposure latitude under tungsten lighting conditions due to a tendency for the red channel to clip early. This seems to be the case, but I’m told there’s a post fix for this problem that I hope to learn about in the near future.

Here’s what I did:

-Shot a Kodak 18% gray card, with some texture to it, at different exposures to see where the camera clipped and to see where significant underexposure noise occurred.

-Shot two tests, one under tungsten light and one under tungsten + full CTB, to see how the camera did under both kinds of light.

-Originally set exposure by setting gray at 50 units using the camera’s Rec 709 output, which turned out to be a stop slower than REDLog would have me believe. Zone 4 on Rec 709 turned out to be Zone 5 in REDLog. (The ASA appears to be a true 320.)

-Took the darkest three tones for each lighting situation and boosted them to 18% gray value to better see noise; also isolated each color channel to see where the noise was coming from.

-Included histograms for each clip from Red Alert.

-Captured in RedCode28, 4K 2:1, 23.98 fps and 1/48 shutter.

I wasn’t able to check underexposure latitude as far down as I wanted because of the ambient light in the test location.

The process was: open .R3D in Red Alert and export clip; then reset white balance to 5600k and capture the histogram to see what the daylight-balanced chip was doing in each situation. The clip was scaled and output as a ProRes HQ Quicktime, 1280x720, and assembled on a ProRes HQ timeline in Final Cut Pro 2. It was then output via Compressor using H.264 VBR encoding at 1k/sec. bit rate, where I tried to keep the file size down without letting the noise get lost or exaggerated by the compression process.

Enjoy!

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Monday, March 17, 2008

It’s All Up to Me Now

I never knew how much processing cameras did for me, until I used a camera that didn’t do any.

My quest for digital truth took me to a little known corner of the world, a private spot where there are three mountains known as The Gains. The middle one, Green Gain, is considered the most stable, and that was where I sought the Guru of all Digital Media.

After a long hike through windy prairies and along steep cliffs I found myself at his abode. At the annointed hour I let myself in and took a seat on the floor opposite the guru’s prayer matte. And then I waited.

An hour later, after discovering that Zen Monthly was simply a magazine designed to help you fill the moments of your life (2,505,600 ideas just for February alone), and realizing that the centerfold model of New Solipsist was actually the editor, I was startled by a voice.

“Sorry I’m late. Take my advice, never buy a British car.”

I half jumped out of my skin. “Where did you come from?”

The Guru pointed to his green robes. “They key very nicely, even in reality. Sorry to sneak up on you like that.” He took his seat across from me. “Tell me, son, what brings you to my retreat.”

I steeled myself, thinking of all the trouble and turmoil that brought me to this point. “It’s very simple,” I said. “I’ve been trying to wrap my mind around this whole ‘RED’ thing and it’s really perplexing. For a long time we’ve all been looking forward to an affordable, raw 4k camera for the masses, and now that we have it… I don’t think we know what to do with it. For myself, I’m learning that there’s an incredible amount that goes into making a digital camera work--and if I’m to make the RED work for me I have to learn how to do in post what other cameras have been doing for me automatically all along.”

The Great Teacher looked sedate, eyes closed, a faint smile on his lips. After a few moments he started. “Ah, sorry about that. Miles away. I do love the Bahamas.”

He leaned closer to me, as if trying to determine whether I could handle the Great Truth he was about to unleash upon me. “Tell me more about these troubles you so desperately wished for.”

“Well, I thought I wanted a camera without any processing built-in,” I whined. “But now I’m learning about all the things that cameras do for me every day that I took for granted. For example, color clipping. I’ve learned that the RED creates these interesting cyan highlights if you shoot under tungsten light, with the RED’s daylight-balanced chip, if you clip the red channel--something that’s easier to do under tungsten light because of the large red component of the spectrum. Apparently it’s not terribly hard to fix and I’m talking with RED about how to accomplish that, after which I hope to publish the solution as a tip on my blog (see ‘Self-Promotion 101,’ New Solipsist, February 2008). But I never knew that this was a common problem solved by the knee circuits in all the other cameras that I use. I know I wished for a raw camera, but now I’m discovering that someone has to take care of all these problems later, and supposedly they can do it better than it can be done in camera--but I’m not sure who that’s going to be. No one knows who will be converting the footage into dailies: is that the rental house that furnished the camera, a post house, an editor who fancies himself a colorist? Will someone do a final color correction pass or will dailies be it? There are so many questions.”

“Ah, grasshopper.” The Guru smiled, seeing a grasshopper nearby. “Now you know why you must be careful what you wish for. Yes, having a camera that dumps a pile of steaming raw data onto your plate, for you to do with what you will, seems attractive at first. THEN you find out how much has been done for you all along without your ever knowing it was happening, and suddenly there’s a new learning curve: it’s not about delivering a pretty picture anymore, it’s delivering footage and making sure someone else turns it into the pretty picture you intended it to be.

“It’s very similar to the problems my old friend, the Film Guru, used to hear all the time. His followers eventually figured it all out, and so will you. I see him less and less these days. I think he’s getting ready to retire. I guess all his silver reclamation schemes paid off.”

The Guru of All Digital Media stood, adjusted his robes, and smiled. “Let me know how things go with RED. I like them, after a fashion. It’ll be interesting to see what evolves.

“Now, if you’ll excuse me, I’m late for a meeting with Sony. I’m trying to talk them out of another prism camera and I’m already overdue. You know, for a guy who’s always supposed to ‘be here now’, I’m always late!”

He slowly started to fade away, his green robe disappearing against the background of reality. “Be careful what you wish for, young man,” he said. “Take my advice and skip the Monkey’s Paw concession on your way out.”

And he was gone.

CamerasPost ProductionProduction • (2) Comments • Most recent comments by: mmorpg, Joofa, • Permalink

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Stunning Good Looks by Art Adams

Art AdamsArt Adams A native of Northern California, Art Adams spent ten years in LA--first at film school (Loyola Marymount) and then working in the film industry. He started out as a camera assistant on low budget features and worked his way into spots, music videos, features, sitcoms and episodic television shows. He transitioned from assistant to operator to DP by the time he returned to the San Francisco Bay Area in 1993.

Currently Art focuses his energies on shooting spots and high end corporate productions, as well as special venue and blue/green screen projects. He likes jobs that make his brain hurt with ingenuity and cleverness. He has been published in HD Video Pro, American Cinematographer, Camera Operator Magazine and Film/Tape World.

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