Here’s a list of some popular external recorders:
- Atomos Samurai
- Atomos Ninja
- Sony SR-R4
- Codex Arriraw
- S.two OB-1
- Convergent Design Nanoflash
- Convergent Design Gemini 4:4:4
- Sound Devices Pix 240i
- Aja Ki Pro
- Aja Ki Pro Mini
Important: Not all signals are read by all recorders. Sometimes, like in the case of Red cameras, the ‘best’ signals are not even passed through for external recording. In the case of the Arri Alexa or Sony F65, the ‘best’ signal is only passed through via the external connectors.
Rule of thumb: Just because you and I speak the same language doesn’t mean we’ll always understand each other. This is true of external recorders as well.
Here’s a simplified table showing data rates that can be expected from external recorders. The table might be incomplete or incorrect. Ask the manufacturer for exact details.
|Cameras/Data||Maximum Data Rate in MB/s||Media|
|Uncompressed 4K 10-bit RGB @ 24 fps||720||Various|
|Sony F65 4K||704||SR Memory|
|Arri Alexa 3K||384||SSD|
|Uncompressed 2K 10-bit RGB @ 24 fps||190||Various|
|Prores/DNxHD HQ 220||27.5||Various|
Now would be a good time to read these, if you haven’t already:
About Containers and Codecs
The Costs of Working with 2K and 4K Uncompressed Footage
Deconstructing RAW, Parts I, II and III.
The common trend among the ‘cheaper’ external recorders is that they don’t record uncompressed video. These recorders transcode the footage internally to either Prores, DNxHD or Cineform, etc.
This is not done to cheat anybody or to cut corners. Manufacturers of such systems know that the filmmakers opting for their products (instead of the ‘higher end’ recorders) probably don’t have the budgets to work with uncompressed footage.
The recorder that stands heads and shoulders above everyone else is the Sony SR-R4, made specifically for the F65. It records at a phenomenal 5.5 Gbps sustained, and that even beats SATA III (6 Gbps) in real-world performance. No wonder Sony had to make something proprietary to read this monster torrent.
Arri Alexa is another camera that pushes a heavy data stream through dual HD-SDI ports (I’ll be covering connectors later), under the proprietary T-link technology.
These data rates are murder for a cash-starved indie filmmaker.
Rule of thumb: Don’t shoot RAW or Uncompressed unless you have the muscle, money, time and manpower to handle such streams.
Playing with a few minutes of uncompressed footage is one thing. Handling hours of uncompressed data is another thing entirely. I suggest you test your readiness to work with such data before you dive in for a full shoot.
- Frame rate and signal protocol match
- Interlacing, psF, progressive signal match
- Options for transcoding to many codecs
- Option of uncompressed recording
- Cheapest media possible
- As many connectors as possible
- Ability to connect to monitor for live feed
- Full audio capability
- Good LCD Monitor for video/format display
- Simple no-frills controls layout
- Rugged construction
- A good friggin’ manual, and 24/7 support!
If you don’t understand some of these terms, read the Understanding Terminology series on wolfcrow.
Since most recorder-camera combinations are unique, it’s hard to give universal recommendations. Sometimes your options are really limited. However, just for fun, the recorder I find the most versatile is the Convergent Design Gemini 4:4:4:
Here are a couple of good videos that explain how external recorders work: