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ARRI Alexa 35


Tim Tyler

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17 Stops of Dynamic Range!

ALEXA 35 is a 4K Super 35 camera that elevates digital cinematography to unprecedented heights. ARRI’s first new sensor for 12 years builds on the evolution of the ALEXA family over that period, delivering 2.5 stops more dynamic range, film-like highlight handling, better low light performance, and richer colors. The new REVEAL Color Science takes full advantage of the sensor’s image quality and provides a fast, simple workflow, while ARRI Textures enhance in-camera creative control. Easy operation, robust build quality, new electronic accessories, and a complete new mechanical support system round out the ALEXA 35 platform.

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ALEXA 35 measures at 17 stops of dynamic range (exposure latitude), far more than any other digital cinema camera. Filmmakers gain 1.5 stops in the highlights and a stop in the shadows over previous ALEXA cameras, while retaining the naturalistic, film-like highlight roll-off. Sophisticated stray-light suppression ensures that the full character and contrast range of each lens is captured. Together, the increased dynamic range and stray light control make it easier to handle any lighting conditions on set, increase flexibility in post, and provide the best possible source for HDR (High Dynamic Range) projects.

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Impressively low noise and sensitivity settings ranging from EI 160 to EI 6400 make ALEXA 35 a “High ISO” camera. An optional Enhanced Sensitivity Mode can be applied to settings between EI 2560 and EI 6400, producing an even cleaner image in low light. This exceptional sensitivity, combined with the wider dynamic range and truer contrast, allows ALEXA 35 to capture the most delicate nuances of light and shadow in a wider range of shooting situations. Filmmakers can work with available light in real locations, safe in the knowledge that even at extreme ISO values, any noise will have a pleasingly film-like structure.

Introduced alongside the ALEXA 35 is REVEAL Color Science, which is the collective name for a suite of image processing steps that, along with the new sensor, help the camera to record more accurate colors with subtler tonal variations. Skin tones of all types and colors are rendered in a flattering, lifelike way. Highly saturated colors such as those in neon signs or car brake lights are captured with incredible realism, as are typically challenging colors like cyan, burgundy, and pastel shades. Overall, the true-to-life color fidelity and amazing resolving power of the sensor make for beautiful, immersive images.

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ARRI Textures provide a new and unique way for cinematographers to exert greater creative control on set. A texture defines the amount and character of grain in an image, as well as the amount of contrast at different levels of detail, perceived by the viewer as sharpness. Previous ALEXA cameras were pre-programmed with a default texture, but with ALEXA 35 you can choose from an evolving menu of custom ARRI Textures, either to suit a specific shooting environment or to hone your look. This allows you to fundamentally alter the way the camera records images, much like selecting a film stock.

With its Super 35 4:3 native 4K sensor, ALEXA 35 can be used with the vast global inventory of existing lenses—modern and vintage, anamorphic and spherical, Super 35 and large format. Filmmakers wanting to shoot with ARRI cameras while having to fulfill 4K mandates now have an immeasurably broader lens choice. A total of 19 recording formats, incorporating efficient in-camera downsampling and anamorphic de-squeezing, allow productions to optimize data rate, resolution, and other parameters, based on their individual needs. Mixed Reality Productions (MRP) will benefit from the camera's ability to record lens metadata in all common standards and output real-time streaming metadata to ARRI's Live Link Metadata Plug-in for Unreal Engine.

ARRI’s discussions with filmmakers and careful review of the image pipeline have led to significant image quality enhancements and a faster, easier workflow. REVEAL Color Science is a suite of new image processing steps used by ALEXA 35 internally and also available through leading third-party postproduction tools for ARRIRAW processing. It includes an improved debayering algorithm for cleaner compositing, a new color engine for more accurate color reproduction, a new wide gamut native color space for faster grading, new LogC4 encoding to contain the increased dynamic range, and new LogC4 LUTs (Look Up Tables) for enriched color fidelity.

ALEXA 35 is the smallest fully featured ARRI production camera ever, packing the features and processing power of a larger ALEXA into a Mini-sized body. Crews will be intuitively familiar with the simple menu structure; support for 1TB and 2TB Codex Compact Drives; and MVF-2 viewfinder, now with HDR. Fast and easy operation is assured through usability improvements such as a new left-side display and additional user buttons. Temperature resistant, splash and dust-proof, and conceived with future hardware and software updates in mind, ALEXA 35 is the best A-camera, B-camera, and drone or gimbal camera on the market, all rolled into one.

ARRI has crafted a new line of bespoke ALEXA 35 accessories that expand the camera's capabilities and ensure maximum speed and versatility on set. Closely integrated electronic accessories offer additional power outputs or extended audio features. A complete new set of mechanical support items provides flexible options for any situation, scaling quickly and easily from a small and lightweight setup to a full-blown production configuration. ALEXA 35 is available in sales sets that group together components suitable for different shooting styles and production types, with further accessories and system options facilitating countless setups.

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Film and Digital Times
ALEXA 35 Camera Report

by Jon Fauer, ASC

(Here's is Jon Fauer's Introduction on Film and Digital Times' comprehensive 90+ page report.)

An ALEXA 35 pre-production test camera was delivered to the FDT office by ARRI’s Guenter Noessner on March 18. The result, 74 days later at camera launch, is this camera report of 96 pages. Initially, the June edition was planned with some pages of ALEXA 35 along with many other products that missed the April deadline. The page count kept growing, a massive Dickensian doorstop. And then, real world supply chain challenges arrived, and not only limited to semiconductors, copper, cars and aluminum. Paper deliveries, and ink for the paper this is printed on, dried up.

But, that is not the only reason all 96 pages are monopolized by ALEXA 35. If you send a camera here three months before deadline, you know that it will be tried, taken out, taken apart, scrutinized and tested like a ship’s open water sea trial. Every angle and surface will be photographed with as much obsession as Col. Henry Charles Baskerville Tanner, the Victorian surveyorartist who mapped the Himalayas.

Moreover, this was the first time a company has made available so many scientists, engineers, executives, product managers, designers, testers and planners to talk about their work in lengthy discussions. Usually a factory visit is a sweaty tour lasting a couple of days, punctuated by a few meetings of short duration. (By the way, “Sweaty Tours” was what film director Mel London called location scouting trips.) This time, it was Zoom that enabled so many fascinating, in-depth interviews.

The new ALEXA 35 is like a film lab inside a digital camera. A film lab is an alchemy of permutations: chemicals, water, temperature, light and human temperament. Let’s forget the dreaded 3 a.m. call, “Oh sorry, the developing machine jammed with all your footage ruined inside.” ALEXA 35 is digital and fortunately doesn’t jam.

And yet, ALEXA 35 offers many hitherto unobtainable digital possibilities that are reminiscent of an analog film process: textures, contrast, grain, sharpness. The digital camera is no longer just a lens onto which you put all kinds of different lenses to achieve unique looks. Now the camera itself returns as an instigator of looks, along with your good looks created by lighting, lenses, composition, art, planning and happy accidents.

I never suspected that something Super35 was afoot at ARRI, not even several years ago when they kept asking why FDTimes was writing so fervently about Full Frame: “But don’t you think there’s room for a new generation Super35 camera?” I must have caused Franz Kraus great agida at Yamazato in Amsterdam one evening after IBC. It wasn’t the sushi, but rather my unknowing (about plans of a new camera) speculation and repetition of Jeff Allen’s observation that “old” 35mm would be relegated to productions that formerly were done in 16mm, while Full Frame would be the “new” replacement for high-end productions that previously shot on 35mm. Little did I know that ALEXA 35, or at least its sensor, had been in development for a decade or more.

It turns out that a camera this interesting and good certainly provides ample room for both formats to continue to coexist salubriously. The 35mm format has been a universal standard ever since the Lumière Brothers projected Workers Leaving the Factory on December 28, 1895 at the Grand Café in Paris. Along the way, cinematographers have enjoyed a vast inventory of 35mm lenses, many of them still cherished and used today. As for ARRI, there has always been a historical affinity of separate cameras for different formats: 16BL and 35BL; 16SR and 535; 416 and 435 and 765. And now: ALEXA 35 for Super35—together with ALEXA Mini LF for Large Format, a.k.a. Full Frame.

If someone told you, “The new ALEXA 35 has 17 stops of dynamic range, prettier images and better color, your inner DP instinct would most likely reply, “Great, but show me.” This healthy skepticism of verbal description—how ironic—is assuaged by viewing real and really good images. They’re here. ARRI’s series of Encounters films shot around the world by eleven talented cinematographers are online (arri.com) with frames and production stills beginning page 81.

ALEXA 35 represents a new chapter in the hundred and five years of ARRI. I hope you enjoy the ALEXA 35 camera system as much as I did trying it and writing all about it.

Read the full report here.

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Damn, very impressive! Well done ARRI. 

Am certain the ALEXA 35 is going to be the #1 preferred choice (when budget allows) for the next five years. 

Fascinating reading the FD Times report on the ALEXA 35. Seems all past cameras they took a waterfall approach to development, but the ALEXA 35 was the first time they used agile development. 

https://www.fdtimes.com/pdfs/free/115FDTimes-June2022-2.04-150.pdf

  

9 hours ago, Phil Rhodes said:

Seventeen stops is an... Interesting claim.

That's more than 131,000:1. Many companies have made interesting dynamic range claims.

This isn't RED! (or others...)

ARRI has historically been more conservative with their DR claims, I'd be inclined to believe them, and that does appear to be what we're seeing. 

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1 hour ago, David Peterson said:

ARRI has historically been more conservative with their DR claims, I'd be inclined to believe them, and that does appear to be what we're seeing. 

Yeah. The problem is, that's a claimed SNR of over 100dB, which is barely possible. If true this number will involve some degree of digital noise reduction, which is probably fine, but it's worth understanding what's really being discussed here. After all the thermal noise of just a resistor at 300K is about -84dBm.

P

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50 minutes ago, Phil Rhodes said:

Yeah. The problem is, that's a claimed SNR of over 100dB, which is barely possible. If true this number will involve some degree of digital noise reduction, which is probably fine, but it's worth understanding what's really being discussed here. After all the thermal noise of just a resistor at 300K is about -84dBm.

P

some low noise cameras (like astronomy cameras) use Peltier elements for cooling down sensors to low temperatures, don't know if Arri does this but it is possible (though using Peltiers consumes lots of power. "digital cinema camera" users are used to having huge power consumption though so if one could save on signal processing power needs there would be some power available to run cooling systems)

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My understanding of this is that active sensor cooling mainly makes sense on long exposures, which is why it's found in astrophotography. I've read at least one paper which suggested it's not particularly helpful for the sort of exposures we use in motion picture work.

The other issue is that its only purpose is to be able to cool things below ambient temperatures, which is impossible with simple forced-air cooling. The problem is, any time you cool something below ambient, it becomes a target for condensation. To speculate wildly, it's possible that the design could use a peltier to cool something more aggressively toward ambient, but it's hard to imagine that being easy to do without risking condensation on at least some part of the device.

So it's possible, but I'd say unlikely.

 

 

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3 hours ago, Phil Rhodes said:

Yeah. The problem is, that's a claimed SNR of over 100dB, which is barely possible. If true this number will involve some degree of digital noise reduction, which is probably fine, but it's worth understanding what's really being discussed here. After all the thermal noise of just a resistor at 300K is about -84dBm.

B&H's video with ARRI's Günter Nösner talks a little about the Alexa 35's application of noise reduction.

 

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11 minutes ago, Tim Tyler said:

B&H's video with ARRI's Günter Nösner talks a little about the Alexa 35's application of noise reduction.

Seems Noise Reduction isn't an option for lower ISO settings. Which kinda makes sense, is unnecessary. 

Thus we know ARRI isn't cheating DR claims by using NR

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5 hours ago, Phil Rhodes said:

Yeah. The problem is, that's a claimed SNR of over 100dB, which is barely possible. If true this number will involve some degree of digital noise reduction, which is probably fine, but it's worth understanding what's really being discussed here. After all the thermal noise of just a resistor at 300K is about -84dBm.

P

Phil—are you taking into consideration the dual-gain sensor path? 
 

Its likely achieved from two 60db-ish data pathways merged together.

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Yes, although at some point there has to be a path from the photosites to the amplifiers. OK, more modern stacked semiconductor manufacturing can provide more flexibility in exactly how this is done, and I would imagine Arri has paid for every modern convenience in pursuit of exactly this sort of performance, but the single biggest issue in every cinema-grade sensor is managing capacitance as these tiny signals go flying around and that isn't a problem that can be entirely worked-around.

Now what happens when they make the LF version of this...

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On 6/2/2022 at 8:12 AM, Phil Rhodes said:

Yes, although at some point there has to be a path from the photosites to the amplifiers. OK, more modern stacked semiconductor manufacturing can provide more flexibility in exactly how this is done, and I would imagine Arri has paid for every modern convenience in pursuit of exactly this sort of performance, but the single biggest issue in every cinema-grade sensor is managing capacitance as these tiny signals go flying around and that isn't a problem that can be entirely worked-around.

Now what happens when they make the LF version of this...

As always your posts are brilliant and enlightening - 

May I ask, what do you mean in terms of managing capacitance? Is that in terms of storing charge at the photosite itself? The MOSFET power follower? The impedance prior to the drain causing noise? Or the actual read-outs running to the column amplifiers and then to ADC?

Thanks

G

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8 hours ago, Gabriel Devereux said:

As always your posts are brilliant and enlightening - 

May I ask, what do you mean in terms of managing capacitance? Is that in terms of storing charge at the photosite itself? The MOSFET power follower? The impedance prior to the drain causing noise? Or the actual read-outs running to the column amplifiers and then to ADC?

Thanks

G

There are two pathways from the dual gain sensor. Every photo-sites output is boosted to a target voltage level before it hits the ADC. The voltage level plus the well capacity determine the saturation point of the photo-site. The ADC matches the range of the incoming signal.  In dual sensors, a separate pathway with lower than  usual  amount of gain is added. The lower amount of gain increases the saturation point(brings back the highlights). The difference in gain determines how many stops can be added to the top of the dynamic range of the dual gain system.  The photo-site itself has a limited dynamic range, but this engineering trick acts like you are combining the readings of two photo-sites at the same location. It also doubles the processing power needed since you are combining 2 frames to get one.

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20 hours ago, d shea said:

There are two pathways from the dual gain sensor. Every photo-sites output is boosted to a target voltage level before it hits the ADC. The voltage level plus the well capacity determine the saturation point of the photo-site. The ADC matches the range of the incoming signal.  In dual sensors, a separate pathway with lower than  usual  amount of gain is added. The lower amount of gain increases the saturation point(brings back the highlights). The difference in gain determines how many stops can be added to the top of the dynamic range of the dual gain system.  The photo-site itself has a limited dynamic range, but this engineering trick acts like you are combining the readings of two photo-sites at the same location. It also doubles the processing power needed since you are combining 2 frames to get one.

I don’t mean to be obtuse but, that isn’t my question. 
At what point is a sensors capacitance reached?

A photo site well doesn’t exist -
A photodiode has a depletion region. A photo site is the area of the photodiode plus circuitry.

In terms of managing capacitance with tiny readouts are we talking about actual latitude of the analogue ‘wire’ the photo sites ‘drain’ as in the depletion region itself of a photodiode or the readout time in relation to the shutter.

I should also add a photo site doesn’t store photons… it’s a common misconception. Instead electrons absorb the magna of energy from the incoming photons and generate a current.

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1 hour ago, Gabriel Devereux said:

I don’t mean to be obtuse but, that isn’t my question. 
At what point is a sensors capacitance reached?

A photo site well doesn’t exist -
A photodiode has a depletion region. A photo site is the area of the photodiode plus circuitry.

In terms of managing capacitance with tiny readouts are we talking about actual latitude of the analogue ‘wire’ the photo sites ‘drain’ as in the depletion region itself of a photodiode or the readout time in relation to the shutter.

I should also add a photo site doesn’t store photons… it’s a common misconception. Instead electrons absorb the magna of energy from the incoming photons and generate a current.

I'm quite sure what you mean by sensor capacitance. Do you mean well capacity of the photodiodide?

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On 6/1/2022 at 4:45 PM, Phil Rhodes said:

Seventeen stops is an... Interesting claim.

That's more than 131,000:1. Many companies have made interesting dynamic range claims.

 

 

 

Originally, TV studio cameras typically had about an 8-stop (~1:256) dynamic range.
256 centimetres is about 8.5 feet,  a little over the height of a typical living room ceiling.
On the same scale, 17 stops would equate to a ceiling about 1.3 kilometres high, about  eight-tenths of a mile!

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