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NAB 2015 Wrap-up by Mark Schubin

June 13th, 2015 | No Comments | Posted in Download, Schubin Cafe

Recorded May 20, 2015
SMPTE DC Bits-by-the-Bay, Chesapeake Beach Resort

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NAB 2015 Wrap-up by Mark Schubin

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B4 Long

April 22nd, 2015 | No Comments | Posted in Schubin Cafe

 

logo_nabshowSomething extraordinary happened at this month’s annual convention of the National Association of Broadcasters in Las Vegas. Actually, it was more a number of product introductions — from seven different manufacturers — adding up to something extraordinary: the continuation of the B4 lens mount into the next era of video production.

Perhaps it’s best to start at the beginning. The first person to publish an account of a working solid-state television camera knew a lot about lens mounts. His name was Denis Daniel Redmond, his account of “An Electric Telescope” was published in English Mechanic and World of Science on February 7, 1879, and the reason he knew about lens mounts was that, when he wasn’t devising new technologies, he was an ophthalmic surgeon.

Baird apparatus 2 croppedIt would be almost half a century longer before the first recognizable video image of a human face could be captured and displayed, an event that kicked off the so-called mechanical-television era, one in which some form of moving component scanned the image in both the camera and the display system. At left above, inventor John Logie Baird posed next to the apparatus he used. The dummy head (A) was scanned by a spiral of lenses in a rotating disk.

1931 Jenkins cameraA mechanical-television camera designed by SMPTE-founder Charles Francis Jenkins, shown at right, used a more-conventional single lens, but it, too, had a spinning scanning disk. There was so much mechanical technology that the lens mount didn’t need to be made pretty.

The mechanical-television era lasted only about one decade, from the mid-1920s to the mid-1930s. It was followed by the era of cathode-ray-tube (CRT) based television: camera tubes and picture tubes. Those cameras also needed lenses.

FernsehkanonenThe 1936 Olympic Games in Berlin might have been the first time that really long television lenses were used — long both in focal length and in physical length. They were so big (left) that the camera-lens combos were called Fernsehkanone, literally “television cannon.” The mount was whatever was able to support something that large and keep it connected to the camera.

In that particular case, the lens mount was bigger than the camera. With the advent of color television and its need to separate light into its component colors, cameras grew.

TK-41 KMTVAt right is an RCA TK-41 camera, sometimes described as being comparable in size and weight to a pregnant horse; its viewfinder, alone, weighed 45 lbs. At its front, a turret (controlled from the rear) carried a selection of lenses of different focal lengths, from wide angle to telephoto. Behind the lens, a beam splitter fed separate red, green, and blue images to three image-orthicon camera tubes.

The idea of hand-holding a TK-41 was preposterous, even for a weight lifter. But camera tubes got smaller and, with them, cameras.

TK-44P 1972 2-person croppedRCA’s TK-44, with smaller camera tubes, was adapted into a “carryable” camera by Toronto station CFTO, but it was so heavy that the backpack section was sometimes worn by a second person, as shown at the left. The next generation actually had an intentionally carryable version, the TKP-45, but, even with that smaller model, it was useful for a camera person to be a weightlifter, too.

HL-35At about the same time as the two-person adapted RCA TK-44, Ikegami introduced the HL-33, a relatively small and lightweight color camera. The HL stood for “Handy-Looky.” It was soon followed by the truly shoulder-mountable HL-35, shown at right.

The HL-35 achieved its small form factor through the use of 2/3-inch camera tubes. The outside diameter of the tubes was, indeed, 2/3 of an inch, about 17 mm, but, due to the thickness of the tube’s glass and other factors, the size of the image was necessarily smaller, just 11 mm in diagonal.

Many 2/3-inch-tubed cameras followed the HL-35. As with cameras that used larger tubes, the lens mount wasn’t critical. Each tube could be moved slightly into the best position, and its scanning size and geometry could also be adjusted. Color-registration errors were common, but they could be dealt with by shooting a registration chart and making adjustments.

B4The CRT era was followed by the era of solid-state image sensors. They were glued onto color-separation prisms, so the ability to adjust individual tubes and scanning was lost. NHK, the Japan Broadcasting Corporation, organized discussions of a standardized lens-camera interface dealing with the physical mount, optical parameters, and electrical connections. Participants included Canon, Fuji, and Nikon on the lens side and Hitachi, Ikegami, JVC, Matsushita (Panasonic), Sony, and Toshiba on the camera side.

To allow the use of 2/3-inch-format lenses from the tube era, even though they weren’t designed for fixed-geometry sensors, the B4 mount (above left) was adopted. But there was more to the new mount than just the old mechanical connection. There were also specifications of different planes for the three color sensors, types of glass to be used in the color-separation prism and optical filters, and electrical signal connections for iris, focus, zoom, and more.

When HDTV began to replace standard definition, there was a trend toward larger image sensors, again — initially camera tubes. After all, more pixels should take up more space. Sony’s solid-state HDC-500 HD camera used one-inch-format image sensors instead of 2/3-inch. But existing 2/3-inch lenses couldn’t be used on the new camera. So, even though those existing lenses were standard-definition, the B4 mount continued, newly standardized in 1992 as Japan’s Broadcast Technology Association S-1005.

Lockheed Martin sensorLockheed Martin cameraThe first 4K camera also sized up — way up. Lockheed Martin built a 4K camera prototype using three solid-state sensors (called Blue Herring CCDs, shown at left), and the image area on each sensor was larger than that of a frame of IMAX film.

As described in a paper in the March 2001 SMPTE Journal, “High-Performance Electro-Optic Camera Prototype” by Stephen A. Stough and William A. Hill, that meant a large prism. And a large prism meant a return to a camera size not easily shouldered (shown above at right).

Bayer filterThat was a prototype. The first cameras actually to be sold that were called 4K took a different approach, a single large-format (35 mm movie-film-sized) sensor covered with a patterned color filter.

An 8×8 Bayer pattern is shown at right, as drawn by Colin M. L. Burnett. The single sensor and its size suggested a movie-camera lens mount, the ARRI-developed positive-lock or PL mount.

separated Bayer colorsOne issue associated with the color-patterned sensors is the differences in spatial resolution between the colors. As seen at left, the red and blue have half the linear spatial resolution of the sensor (and of the green). Using an optical low-pass filter to prevent red and blue aliases would eliminate the extra green resolution; conversely, a filter that works for green would allow red and blue aliases. And, whether it’s called de-Bayering, demosaicking, uprezzing, or upconversion, changing the resolution of the red and blue sites to that of the overall sensor requires some processing.

Abel chartAnother issue is related to the range of image-sensor sizes that use PL mounts. At right is a portion of a guide created by AbelCine showing shot sizes for the same focal-length lens used on different cameras <http://blog.abelcine.com/wp-content/uploads/2010/08/35mm_DigitalSensors_13.jpg>. In each case, the yellowish image is what would be captured on a 35-mm film frame, and the blueish image is what the particular camera captures from the same lens. The windmill at the left, prominent in the Canon 5D shot, is not in the Blackmagic Design Cinema Camera shot.

Whatever their issues, thanks to their elimination of a prism, the initial crop of PL-mount digital-cinematography cameras, despite their large-format image sensors, were relatively small, light, and easily carried. Their size and weight differences from the Lockheed Martin prototype were dramatic.

There was a broad selection of lenses available for them, too — but not the long-range zooms with B4-mount lenses needed for sports and other live-event production. It’s possible to adapt a B4 lens to a PL-mount camera, but an optically perfect adaptor would lose more than 2.5 stops (equivalent to needing about six times more light). Because nothing is perfect, the adaptor would introduce its own degradations to the images from lenses designed for HD, not 4K (or Ultra HD, UHD). And a large-format long-range zoom lens would be a difficult project. So multi-camera production remained largely B4-mount three-sensor prism-based HD, while single-camera production moved to PL-mount single-sensors with more photo-sensitive sites (commonly called “pixels”).

Then, at last year’s NAB Show, Grass Valley showed a B4-mount three-sensor prism-based camera labeled 4K. Last fall, Hitachi introduced a four-chip B4-mount UHD camera. And, at last week’s NAB Show, Ikegami, Panasonic, and Sony added their own B4-mount UHD cameras. And both Canon and Fujinon announced UHD B4-mount long-range zoom lenses.

Grass-Valley-LDX-86The camera imaging philosophies differ. The Grass Valley LDX 86 is optically a three-sensor HD camera, so it uses processing to transform the HD to UHD, but so do color-filtered single-sensor cameras; it’s just different processing. The Grass Valley philosophy offers appropriate optical filtering; the single-sensor cameras offer resolution assistance from the green channel.

sk_uhd4000_xl_1Hitachi’s SK-UHD4000 effectively takes a three-sensor HD camera and, with the addition of another beam-splitting prism element, adds a second HD green chip, offset from the others by one-half pixel diagonally. The result is essentially the same as the color-separated signals from a Bayer-patterned single higher-resolution sensor, and the processing to create UHD is similar.

Panasonic AK-UC3000Panasonic’s AK-UC3000 uses a single, color-patterned one-inch-format sensor. To use a 2/3-inch-format B4 lens, therefore, it needs an optical adaptor, but the adaptor is built into the camera, allowing the electrical connections that enable processing to reduce lens aberrations. Also, the optical conversion from 2/3-inch to one-inch is much less than that required to go to a Super 35-mm movie-frame size.

Ikegami_23-inch_CMOS_4K_cameraSony-HDC-4300Both Ikegami’s UHD camera (left) and Sony’s HDC-4300 (right) use three 2/3-inch-format image sensors on a prism block, but each image sensor is truly 4K, making them the first three-sensor 4K cameras since the Lockheed Martin prototype.  By increasing the resolution without increasing the sensor size, however, they have to contend with photo-sensitive sites a quarter of the area of those on HD-resolution chips, reducing sensitivity.

It might seem strange that camera manufacturers are moving to B4-mount 2/3-inch-format 4K cameras at a time when there are no B4-mount 4K lenses, but the same thing happened with the introduction of HD. Almost any lens will pass almost any spatial resolution, but the “modulation transfer function” or MTF (the amount of contrast that gets through at different spatial resolutions) is usually better in lenses intended for higher-resolution applications, and the higher the MTF the sharper the pictures look.

UA80x9 tilt (2) (1280x805)UA22x8 tilt revised (3) (1280x961)With all five of the major manufacturers of studio/field cameras moving to 2/3-inch 4K cameras, lens manufacturers took note. Canon showed a prototype B4-mount long-range 4K zoom lens, and Fujinon actually introduced two models, the UA80x9 (left) and the UA22x8 (right). The lenses use new coatings that increase contrast and new optical designs that increase MTF dramatically even at HD resolutions.

There is no consensus yet on a shift to 4K production, but 4K B4-mount lenses on HD cameras should significantly improve even HD pictures.  That’s nice!

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Sensor-Lens Options for 4K Acquisition

February 25th, 2015 | No Comments | Posted in Download, Schubin Cafe, Today's Special

Recorded at the 2015 HPA Tech Retreat, Hyatt Regency Indian Wells, CA
February 12, 2015

Are “4K” cameras really 4K? Is de-bayering a form of upconversion? Why should lenses be different for HD and 4K? Why are higher-resolution image sensors usually bigger than HD sensors? Was there ever a real 4K camera? Mark Schubin provides a quick look at sensors and lens options for 4K.

Direct Link (6 MB / 5:40 TRT): Sensor-Lens Options for 4K Acquisition

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Enabling the Fix

April 29th, 2013 | No Comments | Posted in Schubin Cafe

NAB logo

Sometimes cliches are true. Sometimes the check is in the mail. And sometimes you can fix it in post. Amazingly, the category of what you can fix might be getting a lot bigger.

Sonic Notify trimmedAt this month’s NAB show, there was the usual parade of new technology, from Sonic Notify’s near-ultrasonic smartphone signaling for extremely local advertising — on the order of two meters or so (palmable transducer shown at left) to Japan’s National Institute ofARRI-Ikegami-HDK-97ARRI-Camera Information and Communications Technology’s TV “white space” transmissions per IEEE 802.22. In shooting, for those who like the large-sensor image characteristics of the ARRI Alexa but need the “systemization” of a typical studio/field camera, there was the Ikegami HDK-97ARRI (right), with the front end of the former and the back end of the latter.

Dolby 1Even where items weren’t entirely new, there was great progress to be seen. Dolby’s autostereoscopic (no glasses) 3D demo (left) has come a long way in one year. So has the European Project FINE, which can create a virtual-camera viewpoint almost anywhere, based on just a few normally positioned cameras. Last year, there was a lot of processing time per frame; this year, the viewpoint repositioning was demonstrated in real-time.

Leyard 4K wallIf you’re more interested in displays, consider what’s been going on in direct-view LED video. It started out in outdoor stadium displays, where long viewing distances would hide the visibility of the individual LEDs. At NAB 2013, two companies, Leyard (right) and SiliconCore, showed systems with 1.9-mm pixel pitch, leaving the LED structure virtually invisible even at home viewing distances. Is “virtually” not good enough? SiliconCore also showed their new Magnolia panel, with a pitch of just 1.5 mm!

The Leyard display shown here (and at NAB) was so-called “4K,” with more than twice the number of pixels of so-called “Full HD” across the width of the picture. 4K also typically has 2160 active (picture carrying) lines per frame, twice 1080, so it typically has four times the number of pixels of the highest-resolution for of HD.

The Way of the Eagle4K was unquestionably the major unofficial theme on the NAB show floor, replacing the near-ubiquitous 3D of two years ago. There were 4K lenses, 4K cameras, 4K storage, 4K processing, 4K distribution, and 4K displays. Using a form of the new high-efficiency video codec (HEVC), the Fraunhofer Institute was showing visually perfect 4K pictures Inca trimmedwith their bit rates reduced to just 5 Mbps; with the approval of the FCC, that means it could be possible to transmit multiple 4K programs simultaneously in a single U.S. broadcast TV channel. But some other things in the same booth seemed to be attracting more attention, including ordinary HD images, shot by INCA, a tiny, 2.5-ounce “intelligent” camera, worn by an eagle in flight. The eagle is shown above left, the camera, with lens, at right. The seemingly giant attached blue rod is a thin USB cable.

smartphoneThroughout the show floor, wherever manufacturers were highlighting 4K, visitors seemed more interested in other items. The official theme of NAB 2013 was METAMORPHOSIS, with the “ME” intended to stand for media and entertainment, not pure self interest. But most metamorphoses seemed to have happened before the show opened. metamorphosisDigital cinematography cameras aren’t new; neither are second-screen applications. Mobile DTV was introduced years ago. So was LED lighting.

There were some amazing new technologies discussed at NAB 2013 — perhaps worthy of the metamorphosis label.  But they weren’t necessarily on the show floor (at least not publicly exhibited). Attendees at the SMPTE Technology Summit on Cinema (TSC), for example, could watch large-screen bright images that came from a laser projector.

The NAB show was vast, and the associated conferences went on for more than a week. So I’m going to concentrate on just one hour, a panel session called “Advancing Cameras for Cinema,” in one room, the SMPTE TSC, and how it showed the metamorphosis of what might be fixed in post.

1895 MaryConsider the origin of post, the first edit, and it was a doozy! It occurred in 1895 (and technically wasn’t exactly an edit). At a time when movies depicted real scenes, The Execution of Mary, Queen of Scots, in its 27-foot length (perhaps 17 seconds), depicts a living person being led to the chopping block. Then the camera was stopped, a dummy replaced the person, the camera started again, and the head was chopped off. It’s hard to imagine what it must have been like to see it for the first time back then. And, since 1895, much more has been added to the editing tool kit.

It’s now possible to combine different images, generate new ones, “paint” out wires and other undesirable objects, change colors and contrast, and so on. It’s even possible to stabilize jerky images and to change framing at the sacrifice of some resolution. But what if there were no sacrifice involved?

Hitachi-Compact-8K-Camera croppedAstrodesign 8K trimmedThe first panelist of the SMPTE TSC Advancing Cameras session was Takayuki Yamashita of the NHK Science & Technology Research Labs. He described their 8K 120-frame-per-second camera. 8K is to 4K approximately as 4K is to HD, and 120 fps is also four times the 1080i frame rate. This wasn’t a theoretical discussion; cameras were on the show floor. Hitachi showed an 8K camera in a familiar ENG/EFP form (left); Astrodesign showed one dramatically smaller (right).

If pictures are acquired at higher resolutions, they may be reframed in post with no loss of HD resolution. With 8K, four adjacent full-HD-resolution images can be extracted across the width of the 8K frame and four from top to bottom. A shakily captured image that bounces as much as 400% of the desired framing can be stabilized in post with no loss of HD resolution. And the higher spatial sampling rate also increases the contrast ratio of fine detail.

100perc_lin_xHDR_color

Contrast ratio was just one of the topics in the presentation, “Computational Imaging,” of the second panelist, Peter Centen of Grass Valley. Above is an image he presented at the SMPTE summit. The only light source in the room is the lamp facing the camera lens, but every chip on the reflectance chart is clearly visible and so are the individual coils of the hot tungsten filament. It’s an extraordinarily high dynamic range (HDR); a contrast ratio of about ten million to one — more than 23 stops — was captured.

Yes, that was an image he presented at the SMPTE summit — five years ago in 2008. This year he showed a different version of an HDR image. There’s nothing wrong with the technology, but bringing it to the market is a different matter.

Coded apertureAt the 2013 TSC, Centen showed an even older development, one first presented by an MIT-based group at SIGGRAPH in 2007 <http://groups.csail.mit.edu/graphics/CodedAperture>, a so-called “coded aperture.” Consider a point just in front of a camera’s lens. The lens might zoom in or out and might focus on something in the foreground or background. Its aperture might be wide open for shallow depth of field or partially closed for greater depth of field. If it’s a special form of lens (or lenses), it might even deliver stereoscopic 3D. All of those things might happen after the light enters the lens, but all of those possibilities exist in the “lightfield” in front of the lens.

ApertureCoded aperture from MIT paperThere have been many attempts to capture the whole lightfield. Holography is one. Another, used in the Lytro still camera, uses a fly’s-eye type of lens, which can cut into resolution (an NAB demonstration a few years ago had to use an 8K camera for a low-resolution image). A third was described by the third panelist (and shown in his booth on the show floor). The one Centen showed requires only the introduction of a disk with a pattern of holes into the aperture of any lens on any camera.

Centen closeCenten farHere is just one possible effect on fixing things in post, with images from the MIT paper. It is conceivable to change focus distance and depth of field and derive stereoscopic 3D from any single camera and lens combo after it has been shot (click on images to enlarge).

The moderator’s introduction to the panel showed a problem with higher resolutions: getting lenses that are good enough. He showed an example of a 4K lens (with just a 3:1 zoom ratio) costing five times as much as the professional 4K camera it can be mounted on. Centen offered possibilities of correcting both lens and sensor problems in post and of deriving 4K (or even 6K) from today’s HD sensors.

Fraunhofer arrayThe third panelist, Siegfried Foessel of the Fraunhofer Institute, seemed to cover some of the same ground as did Centen — using computational imaging to derive higher resolution from lower-resolution image sensors, increasing dynamic range, and capturing a lightfield, but his versions used completely different technology. The higher resolution and HDR can come from masking the pixels of existing sensors. And the Fraunhofer lightfield capture uses an array of tiny cameras not much bigger than one ordinary one, as shown in their booth (right). Two advantages of the multicamera approach are that each camera’s image looks perfect (with no fly’s eye resolution losses or coded-aperture light losses) and that the wider range of lens positions also allows some “camera repositioning” in post (without relying on Project FINE processing).

Foessel also discussed higher frame rates (as did many others at the 2013 TSC, including a professor of neuroscience and an anesthesiologist). He noted that capturing at a high frame rate allows “easy generation of different presentation frame rates.” He also speculated that future motion-image programming might use a frame rate varying as appropriate.

jotsThe last panelist was certainly not the least. He was Eric Fossum from Dartmouth’s Thayer School of Engineering, but he was introduced more simply, as the inventor of the modern CMOS sensor. His presentation was about a “quanta image sensor” (QIS) containing, instead of pixels, “jots.” The simplest description of a jot is as something like a photosensitive grain from film. A QIS sensor counts individual photons of light and knows their location and arrival time.

An 8K image sensor has more than 33 million pixels; a QIS might have 100 billion jots and might keep track of them a thousand times a second. The exposure curve seems very film-like. Fossum mentioned some other advantages, like motion compensation and “excellent low light performance,” although this is a “longer-term effort” and we “won’t see a camera for some time.”

The “convolution window size” (something like film grain size) can be changed after image acquisition.  In other words, even the “film speed” will be able to be changed in post.

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Walkin’ in a Camera Wonderland

September 20th, 2009 | 3 Comments | Posted in 3D Courses, Schubin Cafe
If you want to see products that don’t appear in U.S. trade-press magazines, you need to go beyond NAB, SMPTE, and InfoCOMM. You need to go to the International Broadcasting Convention.
MR THOMAS FAVELL'S COMPTOMETER

MR THOMAS FAVELL'S COMPTOMETER FOR THE NEW TELESERVER

IBC is my favorite trade show. I can leave work, catch an evening flight to Amsterdam, and take a train directly from the airport to the convention center. If I’m hungry, some exhibitor will be providing food. Thirsty? Water, various forms of coffee, juices, beer, and wine flow freely. IBC even throws a party to which everyone is invited. But none of that is why I like it so much.

Americans tend to forget that we are not alone. Back in the days of RCA cameras, you needed to come to IBC to see those of the UK-based manufacturer Pye.

Today, we tend to think of NAB as an international show. Cameras are shown there by such Japanese manufacturers as Hitachi, JVC, Panasonic, Sony, and Toshiba. And Grass Valley’s cameras at NAB come from Europe. So why bother with IBC? More »

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