Monday, 17 November 2014

Arri ALEXA 65 65mm 6.5K Camera : current overview of specs

This camera looks like a bigger version of the Arri Alexa XT, with the digital viewfinder there is no news of the optical version from the XT Studio.

Here are the official specifications :

Overview :
Camera type 65 mm format digital cinema camera
Sensor ARRI A3X CMOS sensor
Image aperture 5-perf 65 mm (54.12 mm x 25.58 mm active image area)
Sensor resolution 6560 x 3102 (Open Gate – maximum recordable)
Dimensions Length: 387.8 mm | 15.3 in
Width: 208.3 mm | 8.2 in
Height: 163 mm | 6.4 in
(body only with XPL mount)
Weight 10.5 kg | 23.2 lb
Lens mount ARRI XPL mount with Lens Data System (LDS) functionality
Shutter Electronic, 5.0º to 358.0º. Adjustable with 1/10º precision.
Frame rates 20 to 27 fps (Open Gate) *
Exposure index EI 200 to EI 3200. Base sensitivity EI 800
Dynamic range >14 stops

Recording system :
Recording file format Uncompressed ARRIRAW
Recorder crop modes 5-perf 65 mm (Open Gate, 1.78 extraction)
8-perf 35 mm (future)
Storage (type) Codex XR Capture Drive *
Storage (capacity) 480 GByte capacity / 850 MByte per second data rate *
Storage (recording time) 11 minutes @ 24 fps

System interfaces :
Viewfinder Electronic color viewfinder ARRI EVF-1
BNC connectors 4 x 3G SDI
- MON (1) OUT: 2 x 3G SDI
- MON (2) OUT: 2 x 3G SDI
SD card For software updates and menu settings etc. as with ALEXA
New high speed operating mode for fast ARRIRAW frame grabs (planned feature)
Miscellanous interfaces Focus / iris / zoom motor control with full wireless lens control support
5 x RS 24 V
1 x 12 V
TC I/O (5-pin Lemo)
1 x LDD
2 x LCS
BAT and ACC connection

Monitoring and playback :
Monitoring 3 independent color outputs, all with optional overlays:
MON OUT assistive displays:
Zoom, overscan, overlay info, frame lines, false color exposure check, peaking focus check
CDL CDL server support is provided as ALEXA XT
In-camera playback Playback via EVF-1, HD-SDI MON OUT including audio

Open Gate means using the full area of the sensor. The sensor allows for the use of the entire area allocated to the actual sensor or a crop inside to measure an exact pixel size.

* Upgrade planned for Q1/2015. For more information on specifications, check out the official page from Arri.

The most important specifications are the sensor size and resolution. Then comes the lens mount and the data rate.

At this time the Alexa 65 is rental-only.

Comparing the sensor of the Arri ALEXA 65 with others

How big is the sensor of the Arri Alexa 65 and how does it compare to its competition.

The Alexa 65 is the widest sensor (there are some medium format digital sensors out there that are wider, but most of them are older models). It is bigger than traditional 65mm film and even the discontinued Phantom 65.

Here’s a comparison of the sensor of the Alexa 65 with its most important peers, as well as the aspect ratio (native):

Format H. Crop Factor Native Aspect Ratio
Super 35mm 1.40 Various
FF 35mm 1.00 1.5
Phantom 65 0.69 1.67
65mm 0.67 2.28
IQ280 0.67 1.33
Arri Alexa 65 0.69 2.11
IMAX 0.51 1.34

For a large sensor the lens image circle is bigger, which means you will need medium format lenses
For larger apertures, the lenses will be even bigger than their 35mm equivalents.
The center and corner performances of the lenses must be precise. Any imperfections will be blown up on 6.5K.

DOF will be shallower, and pulling focus will also need to be accurate.
The sensor will heat up and Arri claims the two fans used in this camera are ‘very quiet’, though we don’t know at this stage wether it is quiet enough for audio recording.

Speaking of lenses, here’s what Arri has in store for the Alexa 65:

These are rebadged (by IB/E Optics) Hasselblad lenses. The new options are eight primes and one zoom (114mm front diameter):
Lenses 35mm Equivalent Stop Equivalent
24mm T4.8 17 3.3
28mm T4 19 2.8
35mm T3.5 24 2.4
50mm T3.5 35 2.4
80mm T2.8 55 1.9
100mm T2 69 1.4
150mm T3.2 104 2.2
300mm T4.5 207 3.1
Zoom 50-110 T3.5 35-76 2.4

Arri also has a range of Vintage 765 lenses available. Hasselblad lenses are already famous for IMAX and other 65mm work, being some of the finest lenses on earth. However, they are not the only lenses available.

The Arri Alexa 65 uses a new mount called the XPL mount  It has a flange focal distance of 60mm. Here’s how the flange focal distance compares to other medium format lenses:

Mount Flange Focal Distance
Arri PL 52
Leica S 53
Panavision PV 57.15
Mamiya 7/7II 60
Arri Alexa 65 60
Mitchell BNCR 61.47
Hasselblad H 61.63
Mamiya 645 63.3
Bronica 645 ETRS 69
Pentax 645 70.87
Rolleiflex SLX 74
Kiev 60 74.1
Hasselblad 500 74.9
Kowa Six/Super 66 79
Hasselblad/Kiev88 82.1
Pentax 6×7 84.95
Zeiss Ikon Panflex 99.35
Bronica S2A 101.7
Mamiya RZ 105
Mamiya RB 112

Codex Data - Workflow

Codex has released the VaultLab65.

The Alexa 65 can record to the following resolutions:

That’s 0.7 TB/s (though in the official specs the data rate is 850 MB/s) If you shoot a 90-minute movie with a shooting ratio of 5:1, you’ll need about 20 TB. A feature or documentary will easily be in the hundreds of terabytes, and most likely in the Petabytes. The camera does not record in Prores. 

Here is the workflow diagram:

The weight of the Alexa 65 is 10.5 kg – which is almost similar to what the Arricam ST weighs with film loaded so the Alexa 65 will not be as heavy as an IMAX system, but will be similar to using a Super35mm film camera with all the reels one has to carry. The advantage of a 11 minutes-at-a-time (like a film magazine) media card makes this camera shoulder-mount friendly as well:

The Alexa 65 has a frame rate range of 20-27 fps but mostly one will shoot 24 fps. More options are possible in future updates. Even if 120p is possible at 6.5K, the data rate will be a around 3.5 TB/s. This is almost in the realm of science fiction.

Arri ALEXA 65 with the 6K Red Epic Dragon and Sony A7s the Sony A7s is the only other large sensor that can shoot 4K. The Red Epic Dragon is the only camera that can shoot 6K, but with a Super35mm-sized sensor which makes the Alexa 65 special and unique.

The Alexa 65 is a medium format 6.5K recording sensor, made for one main purpose only – to deliver the highest image quality possible. If the dynamic range is greater than 14 stops, and the highlight rendering anywhere near the Alexa XT, this camera is the ultimate cinematographer’s dream for the ultimate project.

Arri ALEXA 65 and who it is for is probably large scale big budget movies. Mega documentaries. And small format movies like The Master, where the goal is to get the ‘medium format look’. Though the price for this look is going to be too steep for the average die-hard fan.

What possibly does the future hold from here. Sony will come out with a similar sensor with 8K of pixels and resolution, and maybe Red will either increase the pixel capture size of current sensors it has had manufactured or be in the process of creating larger sensors. Although it appears the Alexa 65 has drawn a line for 2014 and current in the hands technology.

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