(Page 1 of 1 pages for this article )

Filed under: Cameras •Post Production •

RED ONE Build 14 Latitude Tests

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!

(Page 1 of 1 pages for this article )

                   

 

The Best of Stunning Good Looks Art Adams | 08/30 A directory of my best articles, sorted by topic. This entry is a guide to my best articles, sorted by topic. Enjoy!

4K > 1080P? Matt Jeppsen | 01/30 Why you probably don’t need a 4K TV in your living room There’s a nice, ranty article over at CNET entitled “Why…

LIGHTING STRATEGIES: Rough Guide to Illuminating a Bounce Card Art Adams | 01/29 Lighting a bounce card is easy, right? Right… IF you know the basics. Here they are. Is bounce light really just about aiming a light at a white card and walking away? No. There are a couple of tricks to getting the most out of your bounce source, and I can show them to you fairly quickly using…

You must be registered to comment. This is an effort to reduce spam. Please REGISTER HERE.

Name:

Email:

Location:

URL:

Smileys

Remember my personal information

Notify me of follow-up comments?

Submit the word you see below: