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mohamed el masry · January 9, 2011

hi

i would like to know what is the defrant between red and alexa

thank you

David Mullen ASC · January 9, 2011

hi

i would like to know what is the defrant between red and alexa

thank you

Err... about $30,000???

Both cameras have a 35mm-sized single CMOS sensor with a Bayer filter.

The main difference is the resolution - the Alexa is limited to 2K/HD, whereas the Red One can record up to 4.5K RAW, which allows a 4K post if desired. Currently most people are shooting the Alexa in 1080P HD mode and recording to SxS cards in the Apple ProRes codec (422 or 4444), usually in a Log format. RAW is not yet enabled on the Alexa, but when it does, it will be an uncompressed 2.88K RAW format (from a 3.5K sensor), as opposed to Red's compressed RAW format (Redcode) which varies from 4.5K to lower. There are different levels of Redcode compression that can selected. Red can record to CF cards, hard drives, RAM drives, or SSD cards. The CF or SSD card recorder is mounted/fixed flush into the body, whereas the RAM and hard drives are mounted externally as accessories.

Both cameras are in the 800 ASA range (if you use the newer M-X sensor in the Red One) practically-speaking and both have similar dynamic ranges (around 12 to 13 stops) but the Alexa has a slight edge in terms of noise and dynamic range, the Red (obviously) has the edge in terms of resolution and is a bit less prone to aliasing (either because the higher-res sensor allows for a stronger low-pass filter, or the aliasing in the Alexa is more due to the 1080P format and may be more minimal once RAW recording is allowed.)

The features of both cameras are online in various places.

Keep in mind that ARRIRAW from the Alexa will require some sort of data recorder, and that it's uncompressed so it's a lot of data unless the data recorder itself has a compression scheme that can be selected. RAW recording requires a conversion step to create RGB files.