The Arri Alexa is a film-style digital motion picture camera system made by Arri first introduced in April 2010. The camera marks Arri's first major transition into digital cinematography after smaller previous efforts such as the Arriflex D-20 and D-21. It features modularity, PL mount lenses, a Super 35 sized CMOS sensor shooting up to 2880 x 2160 resolution and supports uncompressed video or proprietary raw (ARRIRAW) data.
The camera is equipped with an onboard SxS card encoder that can record in either Rec. 709 or Log-C to ProRes 422 or ProRes 444 codecs. as well as DNxHD in 1080p resolution. For an additional 1,350 Euros, Alexa camera owners can purchase a software "key" that will unlock the camera's ability to record up to 120fps in ProRes 422 HQ.
The camera is designed for use in high budget feature films, television shows, and commercials, and is widely seen as Arri's answer to the growing acceptance of the Red One camera, along with lower resolution cameras like the Sony CineAlta (35 mm, 1080p), Panavision Genesis (35 mm, 1080p), Thomson Viper FilmStream (2/3", 1080p) to shoot feature films.
Currently there are five different models of the Alexa:
The first camera of the Alexa product family. Introduced in April 2010.
The ALEXA Plus adds integrated wireless remote control, the ARRI Lens Data System (LDS), additional outputs, lens synchronization for 3D, and built-in position and motion sensors.
Alexa Plus 4:3
The ALEXA Plus adds integrated wireless remote control, the ARRI Lens Data System (LDS), additional outputs, lens synchronization for 3D, and built-in position and motion sensors and a 4:3 sensor making it ideal for anamorphic cinematography.
The Alexa M has its imaging and processing unit broken down in two parts to be small, compact and leightweight for 3D rigs and other uses where size is a concern.
The Alexa Studio features an optical viewfinder, mechanical shutter, and a 4:3 sensor making it ideal for anamorphic cinematography.
The Alexa's ALEV III sensor has 3392 × 2200 effective pixels used for generating an image, however, only 2880 × 2160 pixels are used for recording on the Alexa Studio and M in 4:3 mode, and 2880 × 1620 pixels are used for recording on the regular Alexa and other models in 16:9 mode, the rest are used for lookaround in the viewfinder.
The Arri Alexa can record to 1920x1080 ProRes 422 or ProRes 444 on SxS Cards or 2880x1620 ARRIRAW to external recording devices. The Arri Alexa Firmware 7 increases the resolution on the SxS cards to 2k ProRes 4444 (previously 1080p)
ArriRaw is a Raw codec similar to CinemaDNG that contains unaltered Bayer sensor information, the data stream from the camera can be recorded via T-link with certified recorders like those from Codex Digital or Cineflow.
The ArriRaw format (along with the other recordable formats) contains static and dynamic metadata. These are stored in the header of the file and can be extracted with the free web tool metavisor  or with the application Meta Extract provided by Arri. Of particular importance for visual effects are the lens metadata, which are stored only when Arri's lens data system (LDS) is supported by the lens used.
According to cinematographer Roger Deakins, the Alexa's tonal range, color space and latitude exceed the capabilities of film. "This camera has brought us to a point where digital is simply better", says Deakins. Deakins used the camera to shoot the James Bond film Skyfall.
Due to the camera's simplicity of use and high image quality, quite a few network television shows have been shot with the Alexa.
- A Gifted Man (TV)
- Bored to Death (TV)
- Doctor Who (TV)
- Sherlock (TV)
- Extremely Loud and Incredibly Close
- Final Destination 5
- Fringe season 4
- Game of Thrones (TV)
- Grimm (TV)
- Hell On Wheels (TV)
- Homeland (TV)
- How to Make It in America (TV)
- Hugo – Winner of Academy Award for Best Cinematography
- In Time
- Jack and Jill
- Once Upon a Time (TV)
- Pan Am (TV)
- Person of Interest (TV)
- Prime Suspect (TV)
- Revenge (TV)
- Running Wilde (TV)
- Teen Wolf (TV)
- The Chicago Code (TV)
- The Playboy Club (TV)
- The Three Musketeers
- Torchwood: Miracle Day
- Unforgettable (TV)
- Abraham Lincoln: Vampire Hunter
- Amour 
- Bel Ami
- Dracula 3D
- Life of Pi – Winner of Academy Award for Best Cinematography
- Luna Blanca (TV)
- Makapiling Kang Muli (TV)
- One True Love (TV)
- Robot & Frank
- Rock of Ages
- Seeking a Friend for the End of the World
- Skyfall – Nominated for Academy Award for Best Cinematography
- Stefan v/s Kramer
- The Avengers
- The Captured Bird
- The Dictator
- The Five-Year Engagement
- The Gangster Squad
- The Paradise (TV)
- This Is 40 
- What to Expect When You're Expecting
- World War Z
- Zero Dark Thirty 
- 47 Ronin
- Gravity 
- Identity Thief 
- I'm So Excited 
- Iron Man 3 
- Kick-Ass 2 
- Only God Forgives 
- The Last Stand 
- The Lunchbox 
- Thor: The Dark World 
- Vivir a Destiempo 
- Arriflex D-20 and D-21
- Panavision Genesis
- Red One, Red Scarlet-X and Red Epic
- Sony CineAlta PMW-F55 and CineAlta F65
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