IBC: 4K and better pixels

thefilmbook by Benjamin BIn my previous post I discussed digital anamorphic.

I now turn to a second theme of the IBC show, and of its conferences: “4K” resolution, and more generally “better pixels”.

(click on any image in this post for a larger version)


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History of TV Formats in Martin Faehnrich presentation on Ultra-HD -thefilmbook-

Panasonic’s Martin Faehnrich presenting the evolution of TV formats at an IBC conference
As you can see UltraHD in blue is simply four times HD in green
Note that a grey oval is left blank for a possible evolution to 8K in another decade or so…

Outline:

1. 4K and UHD
2. the 4K wave
3. better pixels
4. Arri 2.8K
5. Sony 4K and UHD
6. theaters challenged
7. compression & Rec 2020
8. 2K VFX
9. quality


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1. 4K and UHD

Many of us are already familiar with images close to 4K, created by the “point-and-shoot” cameras in our pockets. For example, the photos in this post are taken with my small Panasonic LX3, which outputs images that are 3968 pixels wide. Obviously, there can be a wide range of quality in 4K images.

The term 4K sometimes leads to misunderstandings due to a confusion between the number of photosites on the sensor versus pixels on the screen. The actual resolution of a camera system depends on the lens, the camera optics, the number of photosites and the signal processing that lead up to the output pixels.

At IBC, most of the talk was not about photosites, but about the pixels in camera outputs and screen displays. Here are the DCI (Digital Cinema Initiative) and HD formats:

4096 × 2160 – DCI 4K projection standard
3840 × 2160 – UltraHD aka UHD aka Quad-HD aka 2160p
2048 x 1080 – DCI 2K projection standard
1920 x 1080 – Full HD aka 1080P aka HD

To speak precisely, I’ll reserve the term 4K for 4096 pixels across, and UHD for 3840 pixels by 2160.

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2. the 4K wave

The first widely-used camera with a 4K output was the Red One introduced in 2007. Red’s 4K resolution was clearly ahead of its time, at a time when most cameras and workflows were HD. The Epic followed in 2011 and Red established a loyal following among some feature filmmakers, and is competing with Arri’s Alexa. At IBC 2013 Red showed its latest offering: the Dragon with a new 6K sensor, with a claim of “16 plus” stops of dynamic range.

The Girl with the Dragon Tattoo by David Fincher with DP Jeff Cronenweth shot with Mysterium X-

The Girl with the Dragon Tattoo remake by David Fincher, shot with Epic & Red One by Jeff Cronenweth, ASC, with 4K post-production

Today 4K is becoming the norm for professional cameras. Sony launched the F65 in 2011, then the F55 and F5 in 2012. Canon introduced its C500 4K camera in 2012. Panasonic is promising a 4K Varicam next year, with a mock-up in a case at IBC. In addition Panavision has given very promising demos of new lenses for its upcoming large-format high-resolution camera.

There are also an increasing number of lower-cost 4K cameras. JVC introduced their camcorder for $5k ($5,000) last year. At IBC Sony presented the PXW-Z100 for $6.5k. It competes with Blackmagic‘s upcoming Production Camera which was shown in a glass case, and announced at $4k without a lens.

A host of 4K & UHD television sets are being offered for the same price as the camcorders. Early-adopter consumers will soon be able to buy 55-inch and 65-inch UHD television sets from LG, Samsung, Sony, Panasonic, Toshiba and others for prices between $3.5k and $6.5k. And everyone expects the prices to go down.

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3. better pixels

The catch phrase of the IBC conferences was that the manufacturers should not simply offer more pixels, but “better pixels”. This is an acknowledgement that resolution is just one of the elements that contribute to image quality. The key elements for 4K cameras, workflows and television distribution that came up were:

- Dynamic Range
- Resolution
- Color
- Bit Depth
- Frame Rate
- Compression

There is often a trade-off between resolution and dynamic range in a camera. For a given sensor area more resolution usually means smaller photosites, which have less dynamic range because they have a shallower “photon well”. This can be offset by intelligent signal processing.

The range and subtlety of colors that can be recorded by the camera is a result of sensor dyes and image processing. Display colors are presently limited to two dominant color spaces: Rec 709 (traditional television) and DCI P3 (digital projection).

The bit-depth for each pixel defines the subtlety of gradations in colors and contrast. I have seen a few examples of amazing finesse in films with 16-bit workflows.

Peter Jackson’s 48 fps version of The Hobbit — shot by Andrew Lesnie ACS, ASC– has drawn mixed reviews, perhaps because he combined both high frame rate and 3D. UHD proponents propose 50 and 60 and 120 fps frame rates to reduce motion blur, to give a clearer view of the action in sports.

Going from HD to UHD is a fourfold increase in storage and workflow processing . Any further improvement in the elements cited above increases the file size and bandwidth requirements beyond that. To deliver UHD to the consumer, manufacturers are betting on the development of H.265 compression (aka HEVC) to lower file sizes.

Successful cameras, workflows and distribution of 4K and UHD will depend on manufacturers finding “sweet spots” with intelligent well-chosen compromises between dynamic range, color, bit-depth, frame rate and compression.

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4. Arri 2.8K

It’s striking that the only major camera manufacturer not to have a 4K camera at IBC was Arri, which presented a new variation on the Alexa sensor, the Amira, designed for documentary use. Alexa’s maximum output resolution in 16:9 is 2880 x 1620, or “2.8K“. The Alexa’s big photosites yield more dynamic range, which is further extended by dual-processing of the high and low parts of the signal.

The Alexa was first introduced in 2010 and presently dominates digital features, with strong competition from Red. The folks at Arri point out that many successful films have been made in 2.8K, and they invited Roger Deakins to IBC last year to discuss using the Alexa on Skyfall by Sam Mendes.

Roger Deakins and Franz Kraus - IBC 2012 - photo by Benjamin B - thefilmbook

Roger Deakins, ASC, BSC, with Franz Kraus after their public discussion at IBC 2012

In the past, Arri’s managing director Franz Kraus has told me that he believes dynamic range is more important than resolution. In an article in the Hollywood Reporter, Kraus states that Arri did not develop a 4K Alexa to avoid sacrificing “dynamic range for resolution”. He also hints at the future possibility of a larger sensor, and adds “we want to develop a camera that continues to deliver high dynamic range as well as greater resolution.”

Stephan Schenk from Arri -thefilmbook-At IBC I asked Arri’s Stephan Schenk when they planned to come out with a new camera, and he told me Arri will not deliver “a new sensor platform for another 15 to 18 months”.

It is of course important for Arri to reassure buyers of Alexas and Amiras that their investments have a certain longevity.

Stephan’s timetable implies that we may see a new Arri camera presented at IBC 2014, and delivered in early 2015.

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5. Sony 4K & UHD

Sony is pushing higher resolution to both ends of the market: 4K professional movie cameras and UHD consumer televisions. Sony’s big F65 camera has a remarkable resolution of 4K green photosites, making it capable of “8K” output in the future. The F65 has a wide color gamut, and delivers 16-bit lin Raw output. The compact, lower-cost F55 and F5 4K cameras are proving popular with independent filmmakers.

Sony’s European cinematography specialists Fabien Pisano and Ainara Porron confirmed that the F65 has just started to be used on feature films this year. They cited Oblivion (by Joseph Kosinski with ASC DP Claudio Miranda), After Earth (by M Night Shyamalan with DP Peter Suschitzky), Venus in Furs (by Roman Polanski, DP Pawel Edelman) and Beauty and the Beast (by Christophe Gans, DP Christophe Beaucarne) in the first batch of F65 features.

Fabien and Ainara stated that there are about 400 F65s worldwide, and 2,500 F55s and F5s. My personal experience is that there are a growing number of 4K projects shot with the F65 and F55, alongside the films shot with Alexas and Epics.

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Sony reps Ainara Porron- Peter Sykes- Fabien Pisano at IBC- photo Benjamin B- thefilmbook

Sony’s Ainara Porron, Peter Sykes & Fabien-Pisano in the IBC 4K screening area

Sony’s Peter Sykes told me that they were opening a Digital Motion Picture Center at Pinewood Studios outside London as a 4K training, demo and test center for filmmakers.

Peter acknowledges that the introduction of UHD is a chicken and egg problem. Consumers clearly need to feel that there is enough high-resolution content to warrant buying a new $5,000 set. He presented a convincing demo with soccer and concert footage shown with Sony’s new 4K projector, and noted that the 2014 World Cup would be shot at 60 fps in 4K. In addition, Sony has launched a 4K download service in the US with 70 movies called Video Unlimited.

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6. theaters challenged

Will UHD be adopted by consumers, or will it disappear from electronics stores like 3D did? I believe that UHD will take hold, but it’s a question of when. We may have to wait a few years before consumers are ready to trade in their existing flat panel set.

If and when consumers adopt UHD, it will create a challenge for movie theaters. Anamorphic filmmaking was developed by the Hollywood studios in the 1950s in part to counter the threat of television. If tomorrow’s audience has large UHD televisions in their home, what will make them come to the theaters? Camera and projection technology may have to raise the bar.

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7. compression & Rec 2020

It was heartening to hear television manufacturers at IBC evoke higher dynamic range, enlarged color gamut and higher frame rates. We must be wary however of attempts to fit that expanded content in existing bandwidth. Obviously much depends on how H.265 pans out; there are estimates of a 50% improvement for the new compression format, but the UHD signal is still 4 times greater than HD. There is no point in having UHD resolution with 8-bit depth or terrible compression to squeeze the signal into an existing broadcast or cable channel.

gamut_rec_2020_dciSome speakers at the IBC conference spoke of the need to draw a “line in the sand” to ensure quality.

Rec 2020 is such an attempt to replace Rec 709 with a minimum quality for UHD, although some have said parts of the proposed standard, like the expanded color space, are unworkable. Others state that Rec 2020′s minimum 10-bit depth is too low. In any case it’s a step in the right direction.

The 3 triangles show the large color space proposed by Rec 2020, the smaller DCI P3 color space (digital projection), and the smallest Rec 709 space (traditional video monitors)

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8. 2K VFX

In the meantime, it can only help UHD to have more 4K finished films to provide content for the future. There is however one elephant in the room: 2K VFX. Most movies currently have visual effects footage produced in 2K, because 4K is deemed too expensive and time-consuming. And some movies shot in 4K do their DI in 2K.

After Earth by M Night Shyamalan - DP Peter Suschitzky-

After Earth by M Night Shyamalan, shot with F65 by DP Peter Suschitzky, ASC, BSC, with 2K VFX and 4K DI

Cinematographer Peter Suschitzky loved shooting with the F65, but he expressed his frustration about 2K VFX upon finishing After Earth, the first F65 film with a 4K post workflow: “There are more than 600 visual-effects shots in the picture, so nearly half the shots in the movie were done in 2K and up-converted to 4K. The effects work is beautifully done, but the resolution isn’t as good as it would be in 4K, which they say is too expensive. That has to change.”

This is both a technological and an economic obstacle. Some have suggested that VFX may evolve in steps, by going to a 3K standard on the way to 4K.

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9. quality

Still, whether pure or up-converted, I for one really enjoyed the richness of some of the 4K images I saw at IBC.

Some of my film-loving friends feel that too much resolution breaks the magic of cinema, because we see too much: every defect of the actor’s skin. I tell them to think of 65mm film. Resolution can bring a finesse to the image, when it is accompanied by other image qualities like an elegant contrast curve and film texture, and the right lens.

And I believe that 4K in the home can drive filmmakers to pursue images of such quality, using digital cameras that will create movies with smooth motion, with high dynamic range, with great subtlety of tones, with beautiful color finesse… With better pixels.

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links

- Standards
wikipedia: DCI 4K spec
streamingmedia.com: What is HEVC (H.265)?
wikipedia: Rec 2020
thefilmbook: My post on Super High Vision 8K
dot.color.com: color space
dot.color.com: Rec 2020 color space

- Cameras
thefilmbook.net: Notes on the Red Dragon
thefilmbook.net: Arri Amira photos & links
hollywood reporter: Arri’s Franz Kraus
thefilmbook.net: Sony F55 photos
procam.tv: The lowdown – F5 F55 F65
redshark news: Blackmagic 4K camera on horizon
thefilmbook.net: Sony 4K PXW-Z100 photos & links
fstopacademy.com : JVC GMY-HMQ10 4K camera Review

wikipedia: list of digital films

- Televisions
techcentral.co.za: Future’s bright for UHD TV: Deloitte

- Distribution
Sony’s Video Unlimited 4K download service (US only)

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IBC PART 1: DIGITAL ANAMORPHIC

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Please don’t hesitate to give me your corrections, via mail, or in the comments below. And, as always, your comments are also welcome.

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5 Responses to “IBC: 4K and better pixels”


  • Merci, Benjamin! Enlightening as always.

    -David Heuring

  • Nedunghattil Dhanil

    Thanks Sir for sharing your brilliant knowledge with us.
    But I think there something still confusing on “Dynamic rage and higher resolution”.
    If one camera gives greater resolution for “X-size” sensor area so the size of photo-sites may be smaller. Theoretically it may deliver smaller dynamic range, but by practice it delivers greater dynamic range than others. If dynamic rage boosting process is happening after the the sensor it may cause to loose the details of the comparatively low and over exposed area.
    And the other way is the sensor grab different images for the high light and mid then the recording-algorithm will combine the both to make a high dynamic rage image. So what will be the result of a shot of highly moving objects? we already have a rolling shutter issue now these too!
    I hope you will find time to clear my doubts.

    • Thank you for your thoughtful comment, Nedunghattil.

      The general principle of more dynamic range with bigger photosite can be offset by other sensor characteristics, like for example the “fill factor” — the percentage of the photosite that is light sensitive.

      Some camera systems like the Arri Alexa stretch the photosite dynamic range by implementing dual signal paths for the high and low parts of the signal.

      You also allude to sequential exposures, one for high and one for low, as is done in the Red Epic’s EXR mode. This approach can create a problem with fast moving subjects, creating double images of high and low exposures.

      Please let me know if I have not addressed your topics.

      All the best
      Benjamin

  • Thank you Sir for your kind replay. This is the perfect answer to my question.

    Nedunghattil Dhanil

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