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Ultrastudio 4k with Arri Alexa on set

PostPosted: Wed Oct 17, 2012 8:39 pm
by fredrik.lindgren
I have recently start to work as a Digital Imaging Technician in the film industry. The ordinary workflow on set if you work with the Alexa is basically saving all data from the camera and applying REC 709 to the offline files in Davinci Resolve, and a bunch of other tasks ofc.

I read about the new Ultrastudio 4k and instantly thought of the possibilities of optimizing the workflow on set. Instead of using the SxS/RED mag cards maybe I could record directly in to my RAID disks with a HD SDI cable from the Alexa, RED epic ect with a full HD resolution and save it as a Quick time file with Apple ProRes 444 conversion. Imagine not have to transcode the REDs r3d files to ProRes but instead record it as ProRes directly, it would save hours of work!

Does this sound plausible? Would I need any other equipment to optimize the security of the image quality?

Re: Ultrastudio 4k with Arri Alexa on set

PostPosted: Fri Oct 19, 2012 8:28 am
by Sareesh Sudhakaran
The Alexa does not output 3K in the SMPTE (HD-SDI) standard, and neither does Red output 4K or 5K via this protocol. If all you want is 1080p then it's okay, but then again why would anyone shoot with these cameras if all they wanted was HD? Maybe if they want the cropping ability, but for that they'll have to record 5K to crop!

The Alexa Arriraw can be recorded to Gemini 4:4:4 (the cheapest option) while Redcode is only written on Redmags. I don't think BMD has a device that can take either of these codecs directly off camera.

What's wrong with SxS or Redmags? Isn't recording to media directly the simplest route? Have I missed something in your workflow?

Re: Ultrastudio 4k with Arri Alexa on set

PostPosted: Sat Oct 20, 2012 9:40 pm
by fredrik.lindgren
Sareesh wrote:The Alexa does not output 3K in the SMPTE (HD-SDI) standard, and neither does Red output 4K or 5K via this protocol. If all you want is 1080p then it's okay, but then again why would anyone shoot with these cameras if all they wanted was HD? Maybe if they want the cropping ability, but for that they'll have to record 5K to crop!

The Alexa Arriraw can be recorded to Gemini 4:4:4 (the cheapest option) while Redcode is only written on Redmags. I don't think BMD has a device that can take either of these codecs directly off camera.

What's wrong with SxS or Redmags? Isn't recording to media directly the simplest route? Have I missed something in your workflow?


All the productions I've been on with the alexa has been shot in 1080p, both feature films and for television. Its obviously much easier to handle than the higher resolutions at the moment, and 1080p you can just enlarge to 2k for DCP projection.

Well I guess I don't need the Ultrastudio 4k then, but maybe a smaller HDlink. If you can output LOG-C from the alexa? Otherwise it would be perfect for applying Look Up Tables and making dailies.

Of course there is noting wrong with recording to SxS cards, I'm just looking for other ways to make the work on set more effective now when the thunderbolt technology is evolving. :D

Re: Ultrastudio 4k with Arri Alexa on set

PostPosted: Mon Oct 22, 2012 10:08 am
by Sareesh Sudhakaran
Well I guess I don't need the Ultrastudio 4k then, but maybe a smaller HDlink. If you can output LOG-C from the alexa? Otherwise it would be perfect for applying Look Up Tables and making dailies.


Yes, you can output LogC.

Maybe you know this already, but the beautiful thing about the Alexa is that you can customize each output with its own gamma via look files.

You create a Look file and then copy that to the camera via the SD card. You can have one look file per output. E.g., one for SxS, one for SDI, and so on. You can record Log C on SxS for post but create a look file just for viewing on set via mon out.

This information will be added to the metadata of the output, so you can use a recorder to record this stream, but the recorder should be able to work with Log C.

I haven't used the HDLink so I can't tell you for certain if they'll match. If you really want an external recorder, why not the Gemini 444? You will always have the option of reading Arriraw when required. I don't think the Gemini supports Log C, though.

Check out this excellent discussion: http://forums.creativecow.net/thread/45/887723

By the way, Arri recommends Prores 444 with LogC, otherwise you might experience banding.

Hope this helps.