35mm film photography comeback?

Discussion in 'Photography' started by Cursitor Doom, Apr 5, 2014.

  1. In fact there is a variable gain low noise amplifier
    between the sensor's analog output and the analog input
    to the ADC.

    That is the way digital cameras have switched ISO values
    until the most recent generation of cameras.

    Until the more recent generations the "sensor", the "ISO
    Amp" and the "ADC" were each discrete, though the amps
    and the ADC's were probably mounted on the same circuit
    board. Today they are all on one chip ("the sensor").
    Each amp and each ADC are dedicated to a single row of
    sensor locations. That is as compared to something
    like perhaps 2 to 12 channels that each take the data
    from multiple rows of sensor locations and feed a chain
    of amps and ADC's on a separate circuit board.

    That basic analog method is still used; however, with
    newer cameras a method of digital amplification is also
    being used. Rather than multiply the digital output,
    the newer ADC's can work with an adjustable comparison
    voltage. By changing the voltage that an analog input
    sample is compared to, ISO values can be changed at the
    digital stage and yet still have the full bit depth
    (which cannot be done with simple multiplication of the
    ADC output).
    It is a variable gain amplifier with a digitally
    programmable gain control too!
    Well, they've been doing exactly that since the middle
    1970's! That is exactly what an OP AMP is. Prior to
    the concept of "integrated circuits" an OP AMP fit your
    description, but was not packaged small enough to solder
    onto a circuit board either.

    That used to be precisely true, but as noted above it is
    not exactly the case with many of the most recent
    Every digital camera that I'm aware of in the past 15
    years as changed ISO with a variable gain analog
    Floyd L. Davidson, Apr 17, 2014
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  2. Cursitor Doom

    Alan Browne Guest

    (1) Counter-rotating is not coaxial (contra-rotating). Counter rotating
    cancels torque only when both engines are operating (at the same power

    (1a) The a/c in the photo has opposite direction turning engines,
    downward bladed outboard which caught my attention - contrast to this

    (2) Seminole, with the blades (properly) downward turning inboard. (eg:
    no "critical" engine).


    (3) v. same direction


    (3a) Critical engine left - you lose that, and the right engine has the
    downgoing blade outboard of the engine - higher yaw couple in climb on
    single engine.

    Again, this is not the same as coaxial (contra-rotating) props like on
    some versions of XF-11 which is similar in form to the P-38 (though
    larger) or the many racing P-51's (etc) that have
    coaxial/contra-rotating props:


    That cancels torque, climb yaw and impingement effects.
    Looking at the photo you posted, it is clear the downgoing blade was
    outboard of the engine, not inboard, on both engines. This means higher
    yaw effect during single-engine climb v. an inboard downgoing blade.

    So it would require strong rudder on the "on" engine side during engine
    failure (eg: dead-foot/dead engine) - and that would apply even if the
    props were contra-rotating coax.
    Alan Browne, Apr 17, 2014
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  3. Cursitor Doom

    Noons Guest

    Yawn.... More unsubstantiated BULLSHIT.
    Try something more actual than CCD technology for 1Mpixdel sensors?
    Why do you think CMOS is so successful? It couldn't be because it allows
    a lot more IC integration, could it?
    What that url describes is old technology for digital imaging, which is
    not used anymore.
    Did you try READING the first sentence?
    Here it is:
    "In the case of digital cameras, ISO sensitivity is a measure of the
    camera's ability to capture light"

    Think about it. Or rather: meditate about it.

    Nope. A programmable analog amplifier is not a continuous variable gain
    amplifier. In CMOS technology for example it's simply a series of fixed
    gain amplifiers that is switched-in or out of the signal path as needed
    to deliver the required amplification.
    There is NOTHING variable about their gain - they are simply added or
    taken out as desired. The sum of their effect is what you and other
    idiots call "variable gain". It's incomparably cheaper and simpler to do
    that with CMOS technology than to design and etch a true variable-gain
    analog amplifier.

    Get some true knowledge of MODERN analog signal processing.
    Or rather: STFU, because your kind of science-by-url-quoting means
    absolutely NOTHING and proves NOTHING.
    Stop quoting text and start UNDERSTANDING and INTERPRETING it.
    And do some research yourself, instead of quoting urls.
    It makes a difference to true knowledge.
    Noons, Apr 18, 2014
  4. Cursitor Doom

    Noons Guest

    Agreed. But I'll note that a diagram of a processing path is NOT the
    actual circuit.
    Until CMOS came up as the main technology for sensors.
    That is a bit older than "most recent generation", no?
    That was the case with CCD technology. Most of it, anyway.
    That is the beauty of CMOS: you can do many things in the same chip with
    the same semiconductor technology. No need for multiple circuit boards
    or mixed silicon - which is incredibly expensive to do.
    That makes a pro-level CMOS chip very expensive.
    Some professional level cameras have such sensors.

    Common, run of the mill cameras - including most amateur dslrs and
    certainly most p&s cameras - don't. They have all the circuitry in the
    sensor, but there is no such thing as individual processing chains per
    row. That still costs a lot to do.

    A sensible and totally correct point! Totally agree. The only thing I'd
    add is that NOT ALL sensors and AD mechanisms work that way.
    Price is still a major factor here, and why there is a SIGNIFICANT
    difference between pro-level sensor cameras and amateur level sensor

    There is no such thing in digital imaging. The circuitry needed to do
    that would introduce unacceptable levels of noise. What thay use is a
    sequential line of simple mosfet low-noise amplifiers that are
    piggy-backed or not as needed by digital switching (I guess we can call
    that programmable). And yes, they have noise problems as well. But
    unlike other technologies, the first stages are the only ones that need
    to be very low-noise. The rest can be standard - aka, cheap - mos

    Disagree. An opamp is NOT low-noise by definition - nor is it variable
    gain either! Yes, they can be configured into variable-gain circuitry,
    but certainly not low-noise one! And if you add the complexity of a
    conventional opamp IC to every row of a sensor, you'll need a prime
    mover to move that sensor! (I'm exaggerating just to drive home the point!)
    741-style opamp ICs have been around for at least 40 years, I used them
    to make analog music synthesizers back in the 70s. But I wouldn't DREAM
    of using a vanilla op-amp IC for low-level, low-noise amplification -
    which is needed if you want to eek out the last bit of photon sensitivity.

    Low-noise IC opamps are NOT easy to integrate into a CMOS chip. But
    mosfet serial-stage amplifiers are dirt easy to make with CMOS
    technology and can work real well with low signals.
    Potentially, they can be less noisy than conventional non-CMOS opamps:
    low-level, low-noise signal processing is almost totally dependent on
    the amount of current passing through the device and mosfet is by its
    very nature inherently low-current technology.
    Yes, I know there are high power audio amp output stages made with
    mosfet transistors. But those use specially made devices and parallel
    layouts to achieve the high currents needed.

    P&S? Not since they all became cmos-chipped. Before that they all did
    curve manipulation, which is why their high ISOs were absolutely
    horrible back then! :)

    As for dslrs, most had a single or a few channels of variable gain
    amplifiers as you described. I'm reminded of the Nikon D2. The
    breakthrough for the current extremely high ISO cameras came when CMOS
    started to be used almost exclusively for the sensors. Adding
    low-level, low-noise serial analog amplifier stages to sensors with that
    technology is child's play, compared to mixed silicon or mixed circuit
    approaches for the older CCD technology.

    Mind you: I still prefer the colour balance of CCD sensors. But that's
    beside the point here and a totally different discussion.

    A LOT of the high ISO is also done by modifying the way the AD is done -
    as you correctly described above- as well as a LOT of it being done by
    manipulating the signal levels a-la HDR.

    There is a good example in the Nikon link provided by nospam where "no
    flash low-light" imaging is described as "high ISO" when the example
    provided really looks more like D-lighting - Nikon's long word for HDR.

    But that Nikon link clearly describes why nospam's arguments about
    "raising ISO is easy and intrinsic" are so flawed. The last sentence
    says it all:

    "We recommend that you raise ISO sensitivity only as high as needed to
    avoid blur."

    "only" means "only".
    Not "always".

    And thanks for injecting a bit of your own knowledge into this. I do
    really object to "argument by url-quoting", which is all the nospams of
    this world are capable of.
    Noons, Apr 18, 2014
  5. The point was that there is in *fact* "a variable gain low
    noise amplifier between the sensor's analog output and the
    input to the ADC." That has nothing to do with any diagram,
    it has to do with the circuits used in cameras.
    It has nothing at all to do with use of CMOS sensors.
    That is used with CCD sensors and with CMOS sensors. My
    reference to "until the most recent" should not be taken
    to mean that it is no longer used, just another method
    is used in *addition* to analog gain.

    The latest Nikon camera, the D4S, has an analog
    amplifier that can be switched to 1x, 2x, and 4x gain
    (it can also be switched in 1/3 and 1/2 stop
    That was historically the case with CMOS too.

    Your attempt to change the goal post by claiming this is
    a distinction between CCD and CMOS is incorrect.
    That does not change the point of contention in the
    original discussion. You repeatedly said there was
    no analog amplifier related to ISO switching, and
    that is not true. There was with CCD sensors in
    2000 and there is with CMOS sensors in 2014.
    It makes the camera less expensive, and produces a much
    better sensor. I'm not positive about the Nikon D3300
    entry level camera, but there is no question that all of
    the current D5xxx and D7xxx Nikon cameras use that
    technology, not to mention all of the FX bodies.
    That is not true.
    That does not agree with what you have been saying in the
    thread previous to now...
    Just everything Nikon has done in the past 3-4 years.
    Can't be significant then. Look at the wonderful
    straight line graphs for ISO versus dynamic range that
    the D5xxx and D7xxx cameras from Nikon produce! Those
    preceded that technology being used in the D4 and D800.
    Don't make silly statements based on the use of

    There have been variable gain amplifiers with digitally
    programmed gain control for an awful long time.
    So you say it isn't done, and then describe one
    technology to do it! Regardless, that proves the point
    that it is done.
    But "low-noise" is not and never was the issue. That is
    not something specific anyway, "low noise" is relative
    to what the design target might be.
    Discrete opamp IC design is exactly what was being done
    with CCD and CMOS designs right up until the last
    generation or two of digital cameras.
    In a current design, true. But they have been used, and
    were until just a blink of an eye past. I'm sure there
    are hundreds of digital camera models still in use that
    are designed exactly that way.
    Who cares about any of that. I has nothing to do with
    what was being discussed. It doesn't support what you
    had previously claimed.
    BS. Stop making stuff up.
    Then why have you maintained over a series of several
    articles that they don't, and further say it can't be
    The D2 generation used CMOS, and it cannot be claimed to
    be a "high ISO" camera. It did not use all these recent
    innovations that you claim were immediate results of
    CMOS. In fact they are just further advances in the
    That statement ignores reality. The high ISO's obtained
    by "modifying" the ADC is a very new technology that has
    just recently been implemented.

    Techniques such as Nikon's Active-D Lighting are done with
    post digitization manipulations.
    "Raising ISO is easy and intrinsic" is correct.
    It means *always* *raise* *it*, as high as is needed.
    How clear can they get?
    Opinions are like assholes, and everyone has one. If
    that is all you have, and it can't be backed up with
    credible and authoritative references that provide
    facts, then you lose when the other guy has valid and
    provable facts that contradict your opinion.
    Floyd L. Davidson, Apr 18, 2014
  6. Cursitor Doom

    Bartolomeo Guest

    W dniu 2014-04-05 21:45, Cursitor Doom pisze:
    I do film and digital. Why?
    There is one attribute of film photography that many don't seem to pay
    much attention too. This is especially true about b&w silver film.
    It is the archival durability that surpasses all current physical data
    media. Of course one can say that with digital you have no problem of
    losing quality with aging. It's true but where would your digital files
    will be 80 years from now? Will you move it each time to newer media
    from the obsolete ones? What if you die and with your death the
    knowledge where the files and backups are die too? Or your great
    grandchildren might find someday a bunch of DVD M-DISC that might be
    still readable but the equipment that could read them will be no longer
    The silver negative without any special care will outlive all your
    digital files. Keep that in mind when throwing away your film camera.
    Bartolomeo, Apr 19, 2014
  7. Cursitor Doom

    nospam Guest

    that's a huge myth. digital will outlast film by a long shot.
    they'll be on whatever storage exists in 80 years.

    where will your negatives be? probably moldy, if a fire or flood hasn't
    destroyed them. you can't make a backup (a copy is a second-generation
    and not as good as the original).
    of course, and that happens any time you buy a new computer or hard
    drive. it can even happen automatically with cloud backup.
    the same thing that happens to the box of negatives and slides you have
    now. if someone wants the images, they will do something to preserve
    them, otherwise they'll be tossed.
    migrate to new media, but even if you don't do that, there will
    probably be a way to read it. other family members probably will have

    and you're assuming they'll even be interested in those photos.

    it's no different than finding old moldy, scratched or faded negatives.
    if you think there will be ways to print film 100 years from now, you
    might be in for a surprise.
    completely wrong. negatives absolutely require care to avoid mold and
    scratches, or damage from fire, flood, etc. there is no way to make a
    backup of film (copies are second generation), so if something happens
    to the original, you lose.

    with digital, you can have unlimited backups, all 100% identical to the
    original, entirely done without any effort whatsoever (other than
    setting up a backup plan initially). you'd have to work at destroying
    all copies.

    digital is without question, more archival than film ever was or will
    nospam, Apr 20, 2014
  8. Cursitor Doom

    Noons Guest

    Sure. But CMOS made it incomparably easier to do.
    Hence why now we have nose-bleed ISO: it was prohibitively expensive to
    do with CCD, a lot cheaper with CMOS.

    Actually, it has a LOT more than just one (1) amplifier...
    Nope. CMOS allows much easier and simpler integration of light sensors,
    analog AND digital circuitry in the SAME silicon waffer. That is what
    makes it a preferable technology: less complexity, cheaper to produce,
    less rejects.
    Of course: an incomplete quote.
    I also specifically said: analog amplifiers are used IN PRO-class cameras.
    Which is what ALL the examples you have provided up to now are.
    Oh, let me see: the D4, all the FX and the top of the line APS-C are p&s
    digital cameras? #facepalm...
    Do you even grasp the notion of a difference in cost between p&s and
    dslr technology?

    That doesn't prove the pro-level CMOS sensor is not expensive.
    It is the main reason the DF is such an expensive camera. Feature-wise,
    the DF is piddly. Slap-in the D4 sensor and watch what happens to its

    Yes it does. The problem is: you do not have the mental capacity to
    read more than one post...

    And that changes what I said where? Familiar with the meaning of "NOT
    ALL"? Hint: Nikon is NOT the only maker of digital cameras. And NOT ALL
    digital cameras are dslrs. And if I didn't restrict my assertion to only
    Nikon, why are you doing so?

    Then why is it that the DF is so expensive when it has a LOT less
    features than the D5X and D7X series? Ah, let me see: marketing bullshit?

    Yes, but not in digital dslr photography. In that realm, they are very
    new. As in: last 3-4 years.

    I never said it isn't done. Learn to read.

    Oh yes IT IS! Amplify a low signal and watch noise unavoidably crop up.
    Hint: high ISO is there to handle low-levels of light, which cause
    low-levels of pixel signal.

    And that makes the opamp itself variable gain? News to me...
    Here is an "authoritative" reference to their use.
    Note the date. I'm quite sure dslrs started being made with that
    technology in 2001?...
    Oh, and read the whole article. It'll show clearly why your reply to
    the next statement is so stupid and uninformed:
    Of course it has and does. You really didn't understand one word of
    what I said above, did you? Ah well, go back to electronics school and
    learn about how to make analog ICs and what the problems are.
    Hint: the article i referenced specifically mentions a low-noise
    pre-amplifier stage. Why would that be if it wasn't relevant for low-noise?
    That applies to you as well. At least I provide references to back MY
    assertions. I don't use references to assertions of others. Which is all
    you and nospam can do. Mostly because you don't have the educational
    background to discuss or argue any of this.

    That is why you quote articles as your arguments, when they should only
    be used as supporting a reasoning of yours. But then again, that is
    common to how education is carried out nowadays: just quote urls, there
    is no need to construct an argument or assertion.
    Isn't it? N0 wonder the "smart people" are not in the USA anymore...

    Because the original posters had no clue what they were talking about
    when they equated p&s and other simpler digital cameras to dslrs and
    pro-level gear.
    They are NOT the same, they are NOT built the same, they do NOT use the
    same technology! Which is the point I've been making all along and you
    have continually missed.

    Blind Freddy could have figured it out, so keep hitting your head
    against logic: it's fun to watch.

    And it is why nosebleed ISOs have only been commercialized from about 3
    years ago, and only for dslrs or similar high class gear. Which part of
    that do you see as a conflict?

    Dunno, let me see: perhaps Nikon should stop using the word "ONLY" when
    according to you they mean "ALWAYS"?
    What, "ONLY" in the Queen's language is a synonym for "ALWAYS"?
    Fantastic - you should be a linguist!

    And your "Credible and authoritative references" are which ones?
    Ah yes: "ONLY" is the same as "ALWAYS". Obviously!...
    Noons, Apr 28, 2014

  9. End of discussion. You have now admitted that every
    single point you initially made was wrong.

    And now you are arguing that everything said to counter
    your claims is in fact right, and claiming are the one
    who said so. Hilarious.
    Floyd L. Davidson, Apr 28, 2014
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