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Filed under: Alexa

Alexa used to film the Avengers

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via arri.com
"The ALEXA had more range and produced a cleaner key in all conditions" says Seamus McGarvey, ASC, BSC. Because of the high number of both interior and exterior visual effects shots, McGarvey undertook extensive testing. "We were going to shoot sometimes on a very large scale in situations where I couldn't control the ambient spill of daylight," he says. "I would have greenscreen lit with hard sun and shade at the same time, within the same shot. One of the first tests I did was to see the tolerance of various camera systems in terms of latitude and ability to extract a key from blue and greenscreen in those ambient lighting conditions. The ALEXA had more range and produced a cleaner key in all conditions." via arri.com

It's one bad-a%$ camera!

Going Wireless

Wireless lens control is quickly becoming really popular on film and TV sets. Essential when using car mounts, jibs, Steadicam and various other types of rigging where the AC can't touch the camera during a shot.

ARRI makes a wonderful system that is actually integrated directly into an Alexa Plus or Studio camera. Other cameras can work off a small box called the UMC-3. You can see a wireless in action here on a Alexa EV with an Alura Zoom lens.

Did you know that wireless tech for cameras was inspired by Radio Controlled cars, airplanes and helicopters? See www.rccaraction.com for all the latest R/C toys for the geek in you.

3D Alexa music-video shoot in Vancouver

Recently I had a chance to join my collegue Sebastian from the Arri Canada office as he taught an Alexa 3D workshop for IATSE in Vancouver.  There was a lot of new technical info that I learned during the two days I was with the class.  3D has a whole new set of rules, guidelines and asthetics that must be paid attention to if you are to create a successful 3D experience for the audience.  Two Alexa Plus cameras were rigged in a mirror setup and Arri wireless remotes were used for focus, iris, zoom as well as convergence (with the use of a second wireless).  Since the Alexas were connected by sync cables, all controls and settings on the Master camera were matched by the Slave camera.  The operation in this 3D configuration was flawless.

On the second day, I got to direct a 3D music video with a group of dancers.  There was a lot to pay attention to including placement, framing and movement on screen.  Depending on close the subject was to the camera, a number a tweaks had to be monitored.  It definitely takes a dedicated team of folks to keep up with a 3D production.

To get started with 3D filmmaking, I suggest you get start with a class that goes over the basics but also give you time on-set to apply what you learned.  The rig we used is similar to the one used by Cameron/Pace group for the film Hugo.  Lots of mirror rigs and side-by-side rigs are now on the market and I look forward to seeing what's new in 3D at NAB 2012.

 

ARRI Alexa VFX metadata extraction | fxguide

Snehal Patel, Sales Associate (Pro Camera Accessories) at ARRI, has been working with Bill Bennett, ASC to test out a workflow for VFX to extract Lens Data and Tilt/Roll information from the Log-C Quicktime files coming out of an Alexa Plus. He posted this information which allows one to extract dynamic per frame Alexa metadata from Alexa files.

It was known that all metadata information was being saved in the Quicktime video file including “per frame” info for things like F-Stop, Focal Length and Zoom data.

Link to the ARRI web page on metadata

The problem was that there were not any metadata readers available for Quicktime that spit out frame-by-frame info. Luckily, ARRI has just released “Meta Extract” for both Mac and PC which is software that runs in a terminal window (command line) and allows you to spit out a semi-colon delimited CSV database file which you can open in Excel. The database is organized by timecode and contains info for every frame in your shot. Some info is static (exposure index, look file, etc.) and other info changes line by line (f-stop, tilt, roll).

Here is the download page for both the instructions (release notes) and software for “Meta Extract”

If you read the PDF it gives precise instructions on how to extract the data.

For example, to extract the metadata for a video file named “A002C016_110719_R33F.mov” on the desktop and make a CSV file called “A002C016_110719_R33F.csv” you would type:

./ARRIMetaExtract /Users/MyUser/Desktop/A002C016_110719_R33F.mov /Users/heugel/Desktop/
A002C016_110719_R33F.csv

This will also extract a look file, in .xml format, that was used for that shot (if one had a Look assigned in the camera) which you can run through the LUT generator to get an LUT without having to go back and find the original Look file.

Snehal Patel explains in his post that when someone wants to look at the CSV file in Excel or another database viewer, make sure they open Excel and do an “import” of the CSV file as opening directly will give you an incorrect display. “During import, be sure to specify that the file is ‘semi-colon delimited’ and don’t reformat the columns. The database opens up and you can see your shot frame-by-frame along with all the metadata that is recorded. To get a list of extracted fields that will show up in the database, see the Meta Extract release notes PDF”.

Here is a direct link to just the PDF

 


via fxguide.com

An article about a forum post I did. VFX peeps should be happy that we got this MetaData Extractor working.

Snehal

Arri Alexa 120fps preview

120 frames per second ability will be coming to the Arri Alexa late this year. This will be at FULL HD resolution of 1920x1080 at ProRes 422HQ setting. Even at this high frame rate, Alexa will still retain the 14stops of Dynamic Range and High sensor sensitivity that the camera has become known for.

Snehal Patel