The ARRI ALEXA is a different beast than RED, it incorporates uncompressed RAW and huge photosites (twice as large as RED) with dual-gain output. All this comes in a package that doesn't compromise build-quality (machined parts, steel sensor holder, entirely sealed electronics...) or handling in comparison to regular professional 35mm cameras - except for the missing optical viewfinder which comes later this year. They worked on cameras for over 90 years, on digital cinema since 15 years and digital cameras since 10 years - you'll notice the difference when you look beyond pure specs from marketing.
The unique, very "filmic" image quality of ALEXA is achieved by generous oversampling (because a 2k-camera cannot generate high-quality 2k-output just as a 4k-camera cannot generate hq-4k-output), high-quality filters, careful internal processing and the low noise-floor and high fill capacity of it's sensor (which is carefully temperated with a cooling system similar in size to some cameras!). Provideocoaliton.com has done a 1:1 comparison (not perfect, the RED is pushed to 800ASA to keep up with ALEXA and the ALEXA only uses it's internal, compressed recording in ProRes) which looks like that:
This is a difference of about 3 stops in actual dynamic range, that's like the difference between a HDSLR and RED. The price is the lower pixel count (which doesn't necessarily mean less detailed images) and the high cost in comparison to a RED MX.
Of course such a tiny jpg from a simple test chart doesn't do it justice, but it gives you an idea why a high dynamic range can result in these crisp, contrasty, yet detailed images we know from 35mm and why the most respected DoPs in Hollywood (Robert Richardson, Roger Deakins...) prefer the ALEXA and don't care about "K".
ARRI itself thinks that a 4k+-workflow with their 35mm-cameras and DI-equipment is still the way to go for high-quality feature film - the ALEXA is more the acceptable digital replacement especially for television-work, 3D or extreme lighting situations.
The EPIC is ideal for a 3D-rig because of it's size (it's not a big difference for steadicam or handheld because balance is more important here) but the sensor is exactly the same as the RED MX despite a few mm in size - the IQ won't be vastly different from "The social network". 120fps vs 60fps? Hard to tell, if you need more than "normal" slow-mo you likely end-up with specialized high-speed cams, anyway. "TSN" is easily the best looking film shot on RED, partly due to the vastly improved sensor but also due to the experienced crew doing a good job hiding it's deficiencies with smart lighting and processing - but it's not 35mm - not even close. The main issue still is the IQ, even on "TSN" and upcoming projects: the skin tones, the tonal transitions in shadows as well as highlights, the dynamic range itself... especially in contrasty scenes, the image just falls apart.
As long Mr. Nolan/Pfister want a "filmic" look with resolution beyond HD, they rather stick with 35mm or even larger formats - Mr. Jackson is much less picky about these things, he rather wants to keep things simple and convenient and compromises IQ which also clearly shows in the poor DIs and Blu-Ray-transfer for LoTR as well as his choice for Super35 instead of anamorphic which wasn't a good idea regarding IQ with it's limited DI-quality at that time.
The unique, very "filmic" image quality of ALEXA is achieved by generous oversampling (because a 2k-camera cannot generate high-quality 2k-output just as a 4k-camera cannot generate hq-4k-output), high-quality filters, careful internal processing and the low noise-floor and high fill capacity of it's sensor (which is carefully temperated with a cooling system similar in size to some cameras!). Provideocoaliton.com has done a 1:1 comparison (not perfect, the RED is pushed to 800ASA to keep up with ALEXA and the ALEXA only uses it's internal, compressed recording in ProRes) which looks like that:
This is a difference of about 3 stops in actual dynamic range, that's like the difference between a HDSLR and RED. The price is the lower pixel count (which doesn't necessarily mean less detailed images) and the high cost in comparison to a RED MX.
Of course such a tiny jpg from a simple test chart doesn't do it justice, but it gives you an idea why a high dynamic range can result in these crisp, contrasty, yet detailed images we know from 35mm and why the most respected DoPs in Hollywood (Robert Richardson, Roger Deakins...) prefer the ALEXA and don't care about "K".
ARRI itself thinks that a 4k+-workflow with their 35mm-cameras and DI-equipment is still the way to go for high-quality feature film - the ALEXA is more the acceptable digital replacement especially for television-work, 3D or extreme lighting situations.
The EPIC is ideal for a 3D-rig because of it's size (it's not a big difference for steadicam or handheld because balance is more important here) but the sensor is exactly the same as the RED MX despite a few mm in size - the IQ won't be vastly different from "The social network". 120fps vs 60fps? Hard to tell, if you need more than "normal" slow-mo you likely end-up with specialized high-speed cams, anyway. "TSN" is easily the best looking film shot on RED, partly due to the vastly improved sensor but also due to the experienced crew doing a good job hiding it's deficiencies with smart lighting and processing - but it's not 35mm - not even close. The main issue still is the IQ, even on "TSN" and upcoming projects: the skin tones, the tonal transitions in shadows as well as highlights, the dynamic range itself... especially in contrasty scenes, the image just falls apart.
As long Mr. Nolan/Pfister want a "filmic" look with resolution beyond HD, they rather stick with 35mm or even larger formats - Mr. Jackson is much less picky about these things, he rather wants to keep things simple and convenient and compromises IQ which also clearly shows in the poor DIs and Blu-Ray-transfer for LoTR as well as his choice for Super35 instead of anamorphic which wasn't a good idea regarding IQ with it's limited DI-quality at that time.
