Sony's new 4K video sensor

Discussion in 'Digital Cameras' started by Alfred Molon, Oct 14, 2012.

  1. Alfred Molon

    Alfred Molon Guest

    - Diagonal 9.33 mm (Type 1/1.7) approx. 12.40M-effective pixels (4072H x
    - Pixel size: 1.85 µm unit pixel
    - Supports 12.40M-pixel imaging at approx. 35 frame/s
    - Back-illuminated CMOS image sensor featuring high sensitivity, high
    dynamic range and low noise
    - Provides 4K video mode (4096H x 2160V, 60 frame/s)
    Alfred Molon, Oct 14, 2012
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  2. Alfred Molon

    Huuter Guest

    For shallow DOF shooting it will present difficulties. The diagonal is
    some 4.6X less than FF. A "normal" view would be at about an 11 mm FL.
    (note the aspect ratios are not 3:2 so the above numbers will vary a
    bit - but the basic idea is there.
    Huuter, Oct 14, 2012
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  3. Alfred Molon

    Alfred Molon Guest

    Yep, but the 60 frames/s at 4K output is impressive.

    By the way, isn't there a way to make an F1 or F0.5 lens for a small
    sensor like this one, to get low DOF?
    Alfred Molon, Oct 14, 2012
  4. Alfred Molon

    Joe Kotroczo Guest

    It's small even for a camcorder sensor, which seems to be the market
    it's been designed for. According to the webpage linked, it's supposed
    to replace current 1/2.3" sensors. I don't even know which camcorders
    use a 1/2.3" chip, most XDCAM ones I'm familiar with are 3-chip cameras,
    either 1/3" or 1/2", with a trichroic beam splitter rather than a Bayer
    Joe Kotroczo, Oct 14, 2012
  5. Alfred Molon

    Huuter Guest

    I seem to recall that there's a limit around f/0.7 or f/0.5 where the
    lens will almost be in contact with the sensor. (That may have been
    limited to a particulart FL &| frame size however). Then (quibble)
    there is the case of the sensor which has a glass cover over the sensor
    proper (a mm or 2?). At these scales that counts.

    The other side of that of course is the cost, not to mention things like
    shutters. I don't know if any/many video cameras use actual shutters
    (like cine film cameras do). Red One (for example) does not have a
    shutter. It also had (has still) a rolling frame issue when the camera
    is panned or when there is fast action.
    Huuter, Oct 14, 2012
  6. Alfred Molon

    Huuter Guest

    With this sensor's back illumination structure (lower noise - good at
    this size), the advantages of trichroic seem to be all but gone (esp.
    when considering optics cost).

    The "movie" people (which drives 4k) seem to be going to RGB sensors
    while ENG seems to be the holdout for trichroic. Some ENG cameras are
    equipped with fabulou$ optics - there may be accompanying reluctance to
    dump trichroic - they also have no needs above 2k (or practically 1280
    if it's strictly "NG").

    As a 4k sensor, the one at hand is not aimed at ENG, obviously.

    Sony must anticipate a market for rather small beyond HD cameras for the
    amateur action film maker... or something like that.
    Huuter, Oct 14, 2012
  7. Alfred Molon

    Me Guest

    The "4.6x less than FF" statement with regard to (shallow) DOF is a bit
    of a red-herring. It's about 2.8x less than (typical) 35mm movie format.
    They still use crews to operate cine cameras, digital or film, with
    "focus pullers" being an important job.
    For ENG where you're not going to have a crew to operate your camera, or
    "home cinema", the deep DOF from smaller sensors is an advantage - not a
    ENG will have an eventual need for UHDTV/4k - if...
    Sport - definitely.
    Home movies shot in UHDTV format will suck (technically) just as badly
    as they did in HD and SD and 8mm.
    I don't think this Sony sensor is for the home movie market.

    Now ITU have released "Rec 2020" for UHDTV in 3840x2160 (as well as the
    "next step" - 7680 x 4320), and the first Rec 2020 compliant TV sets are
    arriving (if you have a spare $20k for a TV - with no UHD content to
    display on it), at least one thing may be being put to rest - whether
    the "next step" from HDTV was to be this format, or "4K" movie format.
    Distribution/broadcasting is the problem.
    More on-topic for this forum, a Rec 2020 compliant UHDTV, which includes
    a new ultra-wide gamut spec and for 10/12 bit colour depth should be
    pretty freaking awesome for still image display and editing.

    If UHDTV "takes off", then theatre owners, some expressing reluctance at
    investing in 4k / 3D projection equipment to upgrade the 2k gear they
    recently bought, might get a little more nervous. If UHDTV format
    movies are available to the home, and I had a 100" UHDTV set, then I
    doubt I'd want to step foot in a cinema ever again. If a movie producer
    made most of their $$ from cinema release, then they're not going to
    want to see their movies released on (UHD) disk in a hurry. The studios
    aren't going to re-master all the movies made over the past decade and
    more, almost all intermediate mastered in 2k, just so they can sell a
    few disks to the faithful, so you may as well stick to the BD version.
    It makes me skeptical that it's all going to take off any time soon.
    Even bluray disk uptake is poor, despite massive advantage over SD/DVD,
    and low cost of equipment.
    Me, Oct 15, 2012
  8. Sure. Glass-Air --- f/0.5 is the theoretical maximum (for
    conventinal lenses. You can build f/0.35, but that's one
    block of glass (with a mirror) and the image is formed
    *inside* the glass:

    In fact American Optical had a f/0.38 lens, and f/0.67 seems to
    be the fastest non-mirror lens. The f/0.7 "back side of the moon"
    lens is probably the best known of the ultra fast lenses.

    Consider the prices for a 50mm f/1.8 , f/1.4, f/1.2, f/1.0
    (all EF lenses from Canon)[1] you can see where the prices for
    a f/0.7 would be --- it'd be many times cheaper to use a normal
    large sensor and a f/1.2 lens and get *much* less DOF than using
    a f/0.7 lens and yon tiny sensor.

    Oh, note that the fastest common zooms are f/2.0. Everything
    faster is not a zoom, AFAICT. So your very fast lens would mean
    one single focal length --- try to sell *that* to someone who
    just bought a very high end (i.e. 4k) cam corder.


    [1] 12k Yen (the II version), 49k Yen, 185k Yen, 359K Yen,
    according to the camera museum, you need to add 23 years(!) of
    inflation to the f/1.0 ... which doubles the price. Then add
    in that the yen is much stronger today ... another factor
    of 1.5, unless I'm mistaken.

    Basically each half-stop over that range quadruples the ---
    towards 1.0 it goes to almost 6x per half-stop. Based on that,
    f/0.7 would be 360 times as expensive as a fast f/1.4 lens.
    Wolfgang Weisselberg, Nov 2, 2012
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