Higher bit conversion in DSLRs unlikely

Discussion in 'Digital Photography' started by Rich, Apr 9, 2006.

  1. Rich

    Rich Guest

    According to one engineer. Going from 12 to 14 or 16 bit A/D
    conversion is unlikely because
    the 14 and 16 bit converters (although they have provide higher
    resolution) have sampling rates
    that are too slow and their power consumption is too high, sometimes
    6-15x higher than
    12 bit converters. I guess it would mean a battery pack like some of
    those medium format
    backs have?
    Rich, Apr 9, 2006
    #1
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  2. Rich

    J. Clarke Guest

    Rich wrote:

    > According to one engineer. Going from 12 to 14 or 16 bit A/D
    > conversion is unlikely because
    > the 14 and 16 bit converters (although they have provide higher
    > resolution) have sampling rates
    > that are too slow and their power consumption is too high, sometimes
    > 6-15x higher than
    > 12 bit converters. I guess it would mean a battery pack like some of
    > those medium format
    > backs have?


    It means waiting. I remember when a machine with less processing power than
    my Palm Pilot filled two floors of a large building and consumed enough
    power to light a small town.

    Funny that after 40 years of seeing Moore's Law at work there are still
    engineers who don't grasp the concept.

    --
    --John
    to email, dial "usenet" and validate
    (was jclarke at eye bee em dot net)
    J. Clarke, Apr 9, 2006
    #2
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  3. Rich

    Roy Smith Guest

    In article <>,
    "J. Clarke" <> wrote:

    > Rich wrote:
    >
    > > According to one engineer. Going from 12 to 14 or 16 bit A/D
    > > conversion is unlikely because
    > > the 14 and 16 bit converters (although they have provide higher
    > > resolution) have sampling rates
    > > that are too slow and their power consumption is too high, sometimes
    > > 6-15x higher than
    > > 12 bit converters. I guess it would mean a battery pack like some of
    > > those medium format
    > > backs have?

    >
    > It means waiting. I remember when a machine with less processing power than
    > my Palm Pilot filled two floors of a large building and consumed enough
    > power to light a small town.
    >
    > Funny that after 40 years of seeing Moore's Law at work there are still
    > engineers who don't grasp the concept.


    When I was in college (graduated 1981), I learned a version of Moore's Law
    that went, "Sooner or later, anything built out of silicon is going to cost
    $5". Forget the flying cars, I'm holding out for a tricorder.
    Roy Smith, Apr 9, 2006
    #3
  4. Rich wrote:
    > According to one engineer. Going from 12 to 14 or 16 bit A/D
    > conversion is unlikely because
    > the 14 and 16 bit converters (although they have provide higher
    > resolution) have sampling rates
    > that are too slow and their power consumption is too high, sometimes
    > 6-15x higher than
    > 12 bit converters. I guess it would mean a battery pack like some of
    > those medium format
    > backs have?
    >

    I don't know what the power consumption of current 12-bit ADCs are
    in DSLRs, but here is one, for example a 14-bit ADC:
    http://focus.ti.com/docs/prod/folders/print/ads5541.html
    that does more than 100 mega samples per second at 710 milliwatts.
    The is faster than the 1D Mark II. And since the time the
    ADC is on is small, I would think that 710 mwatts is OK.
    Since the 1D Mark II processes at 8.5 frames per second,
    the ADC is on less than 0.11 second/frame, so would consume
    only 84 milliwatts/frame.

    Roger
    Roger N. Clark (change username to rnclark), Apr 9, 2006
    #4
  5. Rich

    Rich Guest

    I don't know what the power consumption of the average DSLR is now, but
    it seems
    to me that if people are using them in some situations where they are
    using a flash for
    each shot, the power consumption of the ADC wouldn't be that big an
    issue, by comparison. But the makers of cameras now undoubtedly are
    shooting for shot capacities in the high hundreds of non-flash shots
    per battery charge.
    These ones from Analog Devices seem to consume a good deal more power
    than the
    TI one you found.
    http://www.analog.com/IST/SelectionTable/?selection_table_id=204
    Rich, Apr 9, 2006
    #5
  6. Rich

    Scott W Guest

    Roger N. Clark (change username to rnclark) wrote:
    > Rich wrote:
    > > According to one engineer. Going from 12 to 14 or 16 bit A/D
    > > conversion is unlikely because
    > > the 14 and 16 bit converters (although they have provide higher
    > > resolution) have sampling rates
    > > that are too slow and their power consumption is too high, sometimes
    > > 6-15x higher than
    > > 12 bit converters. I guess it would mean a battery pack like some of
    > > those medium format
    > > backs have?
    > >

    > I don't know what the power consumption of current 12-bit ADCs are
    > in DSLRs, but here is one, for example a 14-bit ADC:
    > http://focus.ti.com/docs/prod/folders/print/ads5541.html
    > that does more than 100 mega samples per second at 710 milliwatts.
    > The is faster than the 1D Mark II. And since the time the
    > ADC is on is small, I would think that 710 mwatts is OK.
    > Since the 1D Mark II processes at 8.5 frames per second,
    > the ADC is on less than 0.11 second/frame, so would consume
    > only 84 milliwatts/frame.
    >
    > Roger

    I think you meant to say 84 mJ / frame not millwatts.

    Scott
    Scott W, Apr 9, 2006
    #6
  7. Scott W wrote:
    > Roger N. Clark (change username to rnclark) wrote:
    >
    >>Rich wrote:
    >>
    >>>According to one engineer. Going from 12 to 14 or 16 bit A/D
    >>>conversion is unlikely because
    >>>the 14 and 16 bit converters (although they have provide higher
    >>>resolution) have sampling rates
    >>>that are too slow and their power consumption is too high, sometimes
    >>>6-15x higher than
    >>>12 bit converters. I guess it would mean a battery pack like some of
    >>>those medium format
    >>>backs have?
    >>>

    >>
    >>I don't know what the power consumption of current 12-bit ADCs are
    >>in DSLRs, but here is one, for example a 14-bit ADC:
    >>http://focus.ti.com/docs/prod/folders/print/ads5541.html
    >>that does more than 100 mega samples per second at 710 milliwatts.
    >>The is faster than the 1D Mark II. And since the time the
    >>ADC is on is small, I would think that 710 mwatts is OK.
    >>Since the 1D Mark II processes at 8.5 frames per second,
    >>the ADC is on less than 0.11 second/frame, so would consume
    >>only 84 milliwatts/frame.
    >>
    >>Roger

    >
    > I think you meant to say 84 mJ / frame not millwatts.


    Yes, that would be the correct unit.
    Roger N. Clark (change username to rnclark), Apr 9, 2006
    #7
  8. Rich

    bmoag Guest

    Power usage is the most easily solved problem as far as the processing
    cirucitry itself is concerned. Decreasing power consumption, and therefore
    heat, is the current mantra for microprocessor design. Heat from excessive
    power requirements is what killed the Pentium 4 for Intel and drove what
    little is left of Apple away from the PowerPC.
    When you go 16 bit color you generate very large files. If current dSLRs
    were to go to 16bit color there is no way to write files of that size, even
    with the fastest Compact Flash cards, that would allow more than single
    frame shooting.
    This too is surmountable.
    Is 16 bit color all that desirable?
    As wonderful as 16 bit color seems we see and print in an 8 bit (and
    actually less, considering the limited color gamuts of viewing and printing
    processes and individual variations in color vision) world.
    Even many sophisticated digital photographers do not really understand, or
    prefer to ignore, the compromises involved in processing images in 16 bit
    color when they are down converted for real world 8 bit use by arbitrary
    device driver algorithms. That supposedly smoother 16 bit histogram is
    irrelevant to the 8 bit driver in the imaging/printing device that is
    incapable of rendering that gradation.
    A bigger advance than 16 bit color would be sensors and processing circuitry
    capable of exposure latitude greater than the current pitiful fractions of
    an f stop.
    bmoag, Apr 9, 2006
    #8
  9. Rich

    Scott W Guest

    bmoag wrote:
    > Power usage is the most easily solved problem as far as the processing
    > cirucitry itself is concerned. Decreasing power consumption, and therefore
    > heat, is the current mantra for microprocessor design. Heat from excessive
    > power requirements is what killed the Pentium 4 for Intel and drove what
    > little is left of Apple away from the PowerPC.
    > When you go 16 bit color you generate very large files. If current dSLRs
    > were to go to 16bit color there is no way to write files of that size, even
    > with the fastest Compact Flash cards, that would allow more than single


    Well this is a pretty crazy idea, that you could not save the images to
    flash. The 20D already saves images in 12 bits per color and so going
    to 16 bits will only be a small increase. Beyond that I often save
    both the raw and the jpeg at the same time, for a total of around 12 MB
    / photo, this is more then what a raw 16 bit / color image would take,
    and any the camera has no problems writing it all to flash.

    Figure the raw file would grow from aound 8 MB to around 10.6 MB, I
    would not call this a very large file.

    Scott
    Scott W, Apr 9, 2006
    #9
  10. Rich

    Bruce Hoult Guest

    In article <>,
    "Rich" <> wrote:

    > I don't know what the power consumption of the average DSLR is now, but
    > it seems
    > to me that if people are using them in some situations where they are
    > using a flash for
    > each shot, the power consumption of the ADC wouldn't be that big an
    > issue, by comparison. But the makers of cameras now undoubtedly are
    > shooting for shot capacities in the high hundreds of non-flash shots
    > per battery charge.


    In fact DSLRs such as the Nikon D70(s) are getting 2000 - 2500 non-flash
    shots per battery charge. And the batteries are pretty small.

    --
    Bruce | 41.1670S | \ spoken | -+-
    Hoult | 174.8263E | /\ here. | ----------O----------
    Bruce Hoult, Apr 9, 2006
    #10
  11. bmoag wrote:

    > Power usage is the most easily solved problem as far as the processing
    > cirucitry itself is concerned. Decreasing power consumption, and therefore
    > heat, is the current mantra for microprocessor design. Heat from excessive
    > power requirements is what killed the Pentium 4 for Intel and drove what
    > little is left of Apple away from the PowerPC.
    > When you go 16 bit color you generate very large files. If current dSLRs
    > were to go to 16bit color there is no way to write files of that size, even
    > with the fastest Compact Flash cards, that would allow more than single
    > frame shooting.
    > This too is surmountable.
    > Is 16 bit color all that desirable?
    > As wonderful as 16 bit color seems we see and print in an 8 bit (and
    > actually less, considering the limited color gamuts of viewing and printing
    > processes and individual variations in color vision) world.
    > Even many sophisticated digital photographers do not really understand, or
    > prefer to ignore, the compromises involved in processing images in 16 bit
    > color when they are down converted for real world 8 bit use by arbitrary
    > device driver algorithms. That supposedly smoother 16 bit histogram is
    > irrelevant to the 8 bit driver in the imaging/printing device that is
    > incapable of rendering that gradation.
    > A bigger advance than 16 bit color would be sensors and processing circuitry
    > capable of exposure latitude greater than the current pitiful fractions of
    > an f stop.


    Like Scott said, we are already writing 12-bits to cards,
    so 16 isn't that much more.

    Good digital cameras have huge dynamic range, much more than film, and
    with more bits to digitize the low end, dynamic range would be better.
    Dynamic range is limited by how many photons you can capture
    and what the read noise is to get the photoelectrons off
    the sensor. Big pixel cameras like the 1D Mark II can store
    as many as 80,000 electrons and have read noise of about 4
    electrons. 80000/4 = 20,000 = 14.3 stops. See:
    http://www.clarkvision.com/imagedetail/evaluation-1d2

    For dynamic range info on sensors, see Table 3 at:
    http://www.clarkvision.com/imagedetail/digital.signal.to.noise

    14-bits would be a big improvement on many cameras, 16-bits
    a modest improvement over 14.

    Roger
    Roger N. Clark (change username to rnclark), Apr 9, 2006
    #11
  12. In article <>, Rich
    <> writes
    >According to one engineer. Going from 12 to 14 or 16 bit A/D
    >conversion is unlikely because
    >the 14 and 16 bit converters (although they have provide higher
    >resolution) have sampling rates
    >that are too slow and their power consumption is too high, sometimes
    >6-15x higher than
    >12 bit converters. I guess it would mean a battery pack like some of
    >those medium format
    >backs have?
    >

    In 1980 I was using what was then a state of the art 20MHz 8-bit
    convertor, a TRW part TDC-1007. Power consumption was around 5W and the
    only reason it was supplied in a 64pin 1inch wide package was so that
    they could get an adequate heat sink onto it! I still have one - the
    biggest ceramic packaged silicon chip I have ever seen. ;-)

    By 1990 ADCs with that performance at less than 1W dissipation in small
    packages were commonplace and the state of the art was the Analogue
    Devices AD9005, I still have one of those, stamped "Prototype". That
    was a 20MHz 12-bit convertor with a power dissipation of 3W.

    By 2000 the monolithic low power equivalent of that AD device was again
    commonplace and we were designing circuits with 16 or more such chips in
    the same space of the old AD9005. By then, state of the art was 16-bit
    devices such as the AD9446, 80MHz 16-bit convertor consuming around 2.5W
    and a more recent version of this will go even faster.

    This should give you some idea of the trend - 4 bits per decade with
    improved power and speed. So anyone that tells you that a 14 or 16bit
    device won't be available now or in the near future with equal or better
    power consumption of a 6 year old 12-bit device (using the Y2K
    introduction date of the D30 dSLR as reference) doesn't have much
    experience as an engineer.
    --
    Kennedy
    Yes, Socrates himself is particularly missed;
    A lovely little thinker, but a bugger when he's pissed.
    Python Philosophers (replace 'nospam' with 'kennedym' when replying)
    Kennedy McEwen, Apr 10, 2006
    #12
  13. On Mon, 10 Apr 2006 10:37:03 +0100, Kennedy McEwen
    <> wrote:

    >In article <>, Rich
    ><> writes
    >>According to one engineer. Going from 12 to 14 or 16 bit A/D
    >>conversion is unlikely because
    >>the 14 and 16 bit converters (although they have provide higher
    >>resolution) have sampling rates
    >>that are too slow and their power consumption is too high, sometimes
    >>6-15x higher than
    >>12 bit converters. I guess it would mean a battery pack like some of
    >>those medium format
    >>backs have?
    >>

    >In 1980 I was using what was then a state of the art 20MHz 8-bit
    >convertor, a TRW part TDC-1007. Power consumption was around 5W and the
    >only reason it was supplied in a 64pin 1inch wide package was so that
    >they could get an adequate heat sink onto it! I still have one - the
    >biggest ceramic packaged silicon chip I have ever seen. ;-)
    >
    >By 1990 ADCs with that performance at less than 1W dissipation in small
    >packages were commonplace and the state of the art was the Analogue
    >Devices AD9005, I still have one of those, stamped "Prototype". That
    >was a 20MHz 12-bit convertor with a power dissipation of 3W.
    >
    >By 2000 the monolithic low power equivalent of that AD device was again
    >commonplace and we were designing circuits with 16 or more such chips in
    >the same space of the old AD9005. By then, state of the art was 16-bit
    >devices such as the AD9446, 80MHz 16-bit convertor consuming around 2.5W
    >and a more recent version of this will go even faster.
    >
    >This should give you some idea of the trend - 4 bits per decade with
    >improved power and speed. So anyone that tells you that a 14 or 16bit
    >device won't be available now or in the near future with equal or better
    >power consumption of a 6 year old 12-bit device (using the Y2K
    >introduction date of the D30 dSLR as reference) doesn't have much
    >experience as an engineer.



    Does anyone remember Bernie Gordon (founder of Analogic) stating
    categorically that there would never be a monolithic integrated 12-bit
    A/D converter?

    Heh.


    rafe b
    www.terrapinphoto.com
    Raphael Bustin, Apr 10, 2006
    #13
  14. Rich

    Rich Guest

    On Mon, 10 Apr 2006 10:37:03 +0100, Kennedy McEwen
    <> wrote:

    >In article <>, Rich
    ><> writes
    >>According to one engineer. Going from 12 to 14 or 16 bit A/D
    >>conversion is unlikely because
    >>the 14 and 16 bit converters (although they have provide higher
    >>resolution) have sampling rates
    >>that are too slow and their power consumption is too high, sometimes
    >>6-15x higher than
    >>12 bit converters. I guess it would mean a battery pack like some of
    >>those medium format
    >>backs have?
    >>

    >In 1980 I was using what was then a state of the art 20MHz 8-bit
    >convertor, a TRW part TDC-1007. Power consumption was around 5W and the
    >only reason it was supplied in a 64pin 1inch wide package was so that
    >they could get an adequate heat sink onto it! I still have one - the
    >biggest ceramic packaged silicon chip I have ever seen. ;-)
    >
    >By 1990 ADCs with that performance at less than 1W dissipation in small
    >packages were commonplace and the state of the art was the Analogue
    >Devices AD9005, I still have one of those, stamped "Prototype". That
    >was a 20MHz 12-bit convertor with a power dissipation of 3W.
    >
    >By 2000 the monolithic low power equivalent of that AD device was again
    >commonplace and we were designing circuits with 16 or more such chips in
    >the same space of the old AD9005. By then, state of the art was 16-bit
    >devices such as the AD9446, 80MHz 16-bit convertor consuming around 2.5W
    >and a more recent version of this will go even faster.
    >
    >This should give you some idea of the trend - 4 bits per decade with
    >improved power and speed. So anyone that tells you that a 14 or 16bit
    >device won't be available now or in the near future with equal or better
    >power consumption of a 6 year old 12-bit device (using the Y2K
    >introduction date of the D30 dSLR as reference) doesn't have much
    >experience as an engineer.


    So does anyone know what 12 bit converters are currently being used
    in various digital cameras? At least that way, you'd know what the
    designers are willing to work with. The cost of 16 bit converters
    is not low, from Analog Devices site, about $50/ea. per 1000-4999.
    That seems like alot for one component of a digital camera aside of
    course from the sensor.
    -Rich
    Rich, Apr 11, 2006
    #14
  15. Rich

    Scott W Guest

    Rich wrote:
    >
    > So does anyone know what 12 bit converters are currently being used
    > in various digital cameras? At least that way, you'd know what the
    > designers are willing to work with. The cost of 16 bit converters
    > is not low, from Analog Devices site, about $50/ea. per 1000-4999.
    > That seems like alot for one component of a digital camera aside of
    > course from the sensor.
    > -Rich

    My guess is most are using one chip to control the CCD and do the A/D
    conversion.
    This seems like the the kind of thing either National or TI might make.

    Scott
    Scott W, Apr 11, 2006
    #15
  16. On Mon, 10 Apr 2006 19:13:06 -0400, Rich <> wrote:


    >So does anyone know what 12 bit converters are currently being used
    >in various digital cameras? At least that way, you'd know what the
    >designers are willing to work with. The cost of 16 bit converters
    >is not low, from Analog Devices site, about $50/ea. per 1000-4999.
    >That seems like alot for one component of a digital camera aside of
    >course from the sensor.
    >-Rich



    The company I work for makes a line of chips used in
    consumer MFPs.

    These chips have (currently) several million gates and
    include a complete three-channel 16-bit analog front-end --
    and cost around $10 in large quantities.

    The AFE is about 1/100 of the functionality of the chip,
    by the way. The chip controls all the functions in a
    typical MFP, including scanner, printer, USB, user
    interface elements, and all image processing.

    <http://www.sigmatel.com/products/multi/mfp/stdc3000.asp>

    See Wolfson for AFEs:

    <http://www.wolfson.co.uk>


    rafe b
    www.terrapinphoto.com
    Raphael Bustin, Apr 11, 2006
    #16
  17. Rich

    Rich Guest

    On Tue, 11 Apr 2006 00:47:19 -0400, Raphael Bustin <>
    wrote:

    >On Mon, 10 Apr 2006 19:13:06 -0400, Rich <> wrote:
    >
    >
    >>So does anyone know what 12 bit converters are currently being used
    >>in various digital cameras? At least that way, you'd know what the
    >>designers are willing to work with. The cost of 16 bit converters
    >>is not low, from Analog Devices site, about $50/ea. per 1000-4999.
    >>That seems like alot for one component of a digital camera aside of
    >>course from the sensor.
    >>-Rich

    >
    >
    >The company I work for makes a line of chips used in
    >consumer MFPs.
    >
    >These chips have (currently) several million gates and
    >include a complete three-channel 16-bit analog front-end --
    >and cost around $10 in large quantities.
    >
    >The AFE is about 1/100 of the functionality of the chip,
    >by the way. The chip controls all the functions in a
    >typical MFP, including scanner, printer, USB, user
    >interface elements, and all image processing.
    >
    ><http://www.sigmatel.com/products/multi/mfp/stdc3000.asp>


    I don't know what the differences are between those multicontrol chips
    and the AD chips, but the price seems pretty cheap.
    -Rich
    Rich, Apr 12, 2006
    #17
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