"digital" flash mode (no actual flash fired) HP945

Discussion in 'Digital Photography' started by David Bindle, Jul 12, 2004.

  1. David Bindle

    David Bindle Guest

    I was just reading what Bob Atkins had to say about the "digital" flash mode
    on the HP945.
    He demonstrates with a mountain scene. It doesn't actually fire the flash at
    all, but it lightens up darker parts of the scene. For some purposes, it
    looks like a good idea to me.

    I wonder, could this technique effectively replace the split neutral density
    filters that are commonly used in mountain scenics where the valleys are so
    much darker than the white capped mountains? (Of course, only in digital
    cameras...)

    Can you achieve this with basically all digital cameras by just reducing the
    contrast settings?

    Are there any other cameras besides the HP945 that has a similar flash, or
    program setting?

    I wonder how well this would work for flashless portraits near full
    telephoto (~300mm equiv.) to bring out shadow detail in the eyes on a sunny
    day.

    Thanks for any help or info you can provide.

    David
     
    David Bindle, Jul 12, 2004
    #1
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  2. David Bindle

    Sabineellen Guest

    >
    >I was just reading what Bob Atkins had to say about the "digital" flash mode
    >on the HP945.
    >He demonstrates with a mountain scene. It doesn't actually fire the flash at
    >all, but it lightens up darker parts of the scene. For some purposes, it
    >looks like a good idea to me.
    >
    >I wonder, could this technique effectively replace the split neutral density
    >filters that are commonly used in mountain scenics where the valleys are so
    >much darker than the white capped mountains? (Of course, only in digital
    >cameras...)
    >
    >Can you achieve this with basically all digital cameras by just reducing the
    >contrast settings?
    >
    >Are there any other cameras besides the HP945 that has a similar flash, or
    >program setting?
    >
    >I wonder how well this would work for flashless portraits near full
    >telephoto (~300mm equiv.) to bring out shadow detail in the eyes on a sunny
    >day.
    >
    >Thanks for any help or info you can provide.
    >
    >David
    >
    >


    Hi... I had the HP 945 for a week now and it's an easily likeable camera,
    though i have not used the digital flash function and don't really have
    intention to anytime soon.

    From what i read, and I assume you probably read it itoo, the advantage of the
    one done on the HP is that the camera does it directly on the fresh CCD data,
    which means it'll probably do it better than JPEG editing on the computer. I
    think it's different from contrast settings in cameras, because this one seems
    a little "intelligent", if that's the right word. Basically, reviewers seemed
    impressed with it, which gave me the impression they probably didn't expect it
    to work, but it did.

    I have no idea how it'd perform on a sunny day portrait, but i have the vague
    impression that i read somewhere that it can be used for such situations of
    harsh shadows on sunny days and that it does actually work. That said though,
    the camera has up to +/-3 in exposure compensation which is the usual trick,
    plus a spot metering mode. Those two are what is usually used for such
    situations, at least in 35mm photography.

    I also vaguely remember reading one user review that said indoors it could turn
    a black hair gray, but that was the only negative comment i read regarding it.

    Maybe i ought to try it for you.

    The only other camera that has it is the newer HP camera, HP Photosmart R707,
    just out lately.
     
    Sabineellen, Jul 13, 2004
    #2
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  3. "David Bindle" <> writes:

    > I was just reading what Bob Atkins had to say about the "digital" flash mode
    > on the HP945.
    > He demonstrates with a mountain scene. It doesn't actually fire the flash at
    > all, but it lightens up darker parts of the scene. For some purposes, it
    > looks like a good idea to me.
    >
    > I wonder, could this technique effectively replace the split neutral density
    > filters that are commonly used in mountain scenics where the valleys are so
    > much darker than the white capped mountains? (Of course, only in digital
    > cameras...)


    The problem is most digital cameras have a lot less range than print films do,
    between dark and light. Slide films have the same sort of problems, and the
    solution is typically the same (expose to avoid burning out the highlights and
    bring out shadow detail in post processing). In the most common case of JPEG,
    there are only 8 bits (values 0-255) for each color per pixel. With some
    cameras by going to the RAW formats, you get a bit more range. I suspect that
    in general you will get better results under a photo editor like photoshop or
    gimp than with the camera doing the processing.

    --
    Michael Meissner
    email:
    http://www.the-meissners.org
     
    Michael Meissner, Jul 13, 2004
    #3
  4. David Bindle

    Paul H. Guest

    "David Bindle" <> wrote in message
    news:ccv0c6$fm4$...
    > I was just reading what Bob Atkins had to say about the "digital" flash

    mode
    > on the HP945.
    > He demonstrates with a mountain scene. It doesn't actually fire the flash

    at
    > all, but it lightens up darker parts of the scene. For some purposes, it
    > looks like a good idea to me.
    >
    > I wonder, could this technique effectively replace the split neutral

    density
    > filters that are commonly used in mountain scenics where the valleys are

    so
    > much darker than the white capped mountains? (Of course, only in digital
    > cameras...)
    >
    > Can you achieve this with basically all digital cameras by just reducing

    the
    > contrast settings?
    >
    > Are there any other cameras besides the HP945 that has a similar flash, or
    > program setting?
    >
    > I wonder how well this would work for flashless portraits near full
    > telephoto (~300mm equiv.) to bring out shadow detail in the eyes on a

    sunny
    > day.
    >
    > Thanks for any help or info you can provide.
    >
    > David




    David, while it's neat that the HP-945 provides this function in-camera, the
    same sort of "digital flash" can be applied out of the camera using any
    fairly sophisticated photo editor such as Photoshop or Photoshop Elements.
    The technique is called "constrast masking" and is used to selectively
    brighten darker portions of an image while leaving the brighter parts
    relatively untouched. Actually, "contrast masking" is a bit of a misnomer;
    "luminance enhancement" would probably be a better term.

    Here's how it's done in Photoshop Elements. With an image loaded into the
    program,

    1) Duplicate the image layer and make the duplicate layer the active layer
    2) De-saturate the layer (ctrl-shift-U)
    3) Invert the layer (ctrl-I)
    4) Set the blending mode of the layer to "Overlay" or "Soft Light". Overlay
    provides greater contrast.
    5) Set the layer transparency to around 80%.
    6) Apply a Gaussian blur to the layer. Start with something around 50 and
    work up/down from there. The purpose of this blurring step is to reduce the
    severity of the transitions between light and dark areas in the photo to
    avoid that awful cut-and-paste look.
    7) Optional--Play around with steps 4, 5 and 6 to get the most pleasing
    result.
    8) Flatten the image (ctrl-E)
    9) Optional--Adjust Levels or Brightness/Contrast, if desired
    10) Save the picture under a different name.

    If you've never done this before, it might sound complicated, but it really
    isn't in practice. Just a few keystrokes/button-presses and you've got an
    amazingly enhanced picture in many cases and you can often even turn
    throw-away shots into real keepers using this technique. ("Yes--now you can
    turn TRASH into CASH!" as an infomercial might put it.) Also, if you're
    using full Photoshop, not Elements, you can turn this process into an
    action. Finally, to answer your other question, enhancing
    brightness/contrast on a digital camera simply can't duplicate the
    digital-flash/contrast-masking effect.

    I'd rather do my "digital flashing" outside the camera anyway since I have
    far more control over the finished result, though as I said above, it *is*
    an interesting feature to include in a digital camera. BTW,
    www.steves-digicams.com has an HP-945 review with a couple of digital-flash
    examples along with their normally-shot counterparts so you can try out
    contrast masking on your own to see how it compares to HP's implementation.

    Hope this helps.
     
    Paul H., Jul 13, 2004
    #4
  5. In article <>,
    m says...

    > Actually, "contrast masking" is a bit of a misnomer;
    > "luminance enhancement" would probably be a better term.
    >
    > Here's how it's done in Photoshop Elements. With an image loaded into the
    > program,


    [snip excellent step-by-step]

    > Hope this helps.


    Indeed! Thanks for posting this; it's a great tool to add to my quiver.

    --
    Charles Jones -- Loveland, Colorado
    ICQ: 29610755
    AIM: LovelandCharles
    Y!M: charlesjonesathpcom
    MSN:
     
    Charles Jones, Jul 14, 2004
    #5
  6. David Bindle

    Guest

    Michael Meissner <> wrote:

    > The problem is most digital cameras have a lot less range than print
    > films do, between dark and light. Slide films have the same sort of
    > problems, and the solution is typically the same (expose to avoid
    > burning out the highlights and bring out shadow detail in post
    > processing). In the most common case of JPEG, there are only 8 bits
    > (values 0-255) for each color per pixel.


    Yeah, but usually those 8 bits represent a value that you raise to the
    power 2.2 to get luminance. When you work that out, 8 bits is a heck
    of a dynamic range.

    From what I can see, digital sensors (or at least those in DSLRs) have
    more dynamic range than transparencies but less than print film. It
    may be that with a drum scanner you can squeeze a bit more out of a
    transparency.

    > With some cameras by going to the RAW formats, you get a bit more
    > range. I suspect that in general you will get better results under
    > a photo editor like photoshop or gimp than with the camera doing the
    > processing.


    Yup.

    Andrew.
     
    , Jul 24, 2004
    #6
  7. lid writes:

    > Michael Meissner <> wrote:
    >
    > > The problem is most digital cameras have a lot less range than print
    > > films do, between dark and light. Slide films have the same sort of
    > > problems, and the solution is typically the same (expose to avoid
    > > burning out the highlights and bring out shadow detail in post
    > > processing). In the most common case of JPEG, there are only 8 bits
    > > (values 0-255) for each color per pixel.

    >
    > Yeah, but usually those 8 bits represent a value that you raise to the
    > power 2.2 to get luminance. When you work that out, 8 bits is a heck
    > of a dynamic range.


    The classic counterexample is shooting weddings, and trying to get detail in
    both the bride's white dress and the groom's black tux. From what I've read,
    most digital cameras give you the range of slide film, but print film still
    gives more latitude.

    > From what I can see, digital sensors (or at least those in DSLRs) have
    > more dynamic range than transparencies but less than print film. It
    > may be that with a drum scanner you can squeeze a bit more out of a
    > transparency.


    I believe in general you only get that extended range in DSLRs when you use raw
    mode, which for many cameras can give you 10-12 bits of precision. I believe
    some of the newer Fujis are trying to address the dynamic range problem by
    having two sensors for the high and low values. And even the Sigmas are trying
    to attack the problem, its a pity that the implementation leaves a lot to be
    desired compared to the theory.

    I suspect within 5 years or so, there will be a shift to using 16-bit formats
    in cameras. As bragging rights, I would hope the megapixel race is nearly
    over, and manufacturers start concentrating on higher ISO values (with less
    noise) and more tonality.

    --
    Michael Meissner
    email:
    http://www.the-meissners.org
     
    Michael Meissner, Jul 24, 2004
    #7
  8. David Bindle

    Guest

    Michael Meissner <> wrote:
    > lid writes:


    >> Michael Meissner <> wrote:
    >>
    >> > The problem is most digital cameras have a lot less range than print
    >> > films do, between dark and light. Slide films have the same sort of
    >> > problems, and the solution is typically the same (expose to avoid
    >> > burning out the highlights and bring out shadow detail in post
    >> > processing). In the most common case of JPEG, there are only 8 bits
    >> > (values 0-255) for each color per pixel.

    >>
    >> Yeah, but usually those 8 bits represent a value that you raise to the
    >> power 2.2 to get luminance. When you work that out, 8 bits is a heck
    >> of a dynamic range.


    > The classic counterexample is shooting weddings, and trying to get detail in
    > both the bride's white dress and the groom's black tux.


    But that's not really a counterexample: there's no way that the ratio
    of tux/dress exceeds the dynamic range of a JPEG encoded at gamma 2.2.
    The limiting factor is still sensor noise.

    > From what I've read, most digital cameras give you the range of
    > slide film, but print film still gives more latitude.


    >> From what I can see, digital sensors (or at least those in DSLRs)
    >> have more dynamic range than transparencies but less than print
    >> film. It may be that with a drum scanner you can squeeze a bit
    >> more out of a transparency.


    > I believe in general you only get that extended range in DSLRs when
    > you use raw mode, which for many cameras can give you 10-12 bits of
    > precision.


    What raw gives you is linear encoding, at least with CCDs. That gives
    you an opportunity to use curves somehow to squeeze that huge dynamic
    range into that of a print -- which has Dmax 1.2 if you're lucky.

    > I suspect within 5 years or so, there will be a shift to using
    > 16-bit formats in cameras.


    Actively cooled sensors, maybe?

    Andrew.
     
    , Jul 25, 2004
    #8
  9. lid writes:

    > Michael Meissner <> wrote:
    > > lid writes:

    >
    > >> Michael Meissner <> wrote:
    > >>
    > >> > The problem is most digital cameras have a lot less range than print
    > >> > films do, between dark and light. Slide films have the same sort of
    > >> > problems, and the solution is typically the same (expose to avoid
    > >> > burning out the highlights and bring out shadow detail in post
    > >> > processing). In the most common case of JPEG, there are only 8 bits
    > >> > (values 0-255) for each color per pixel.
    > >>
    > >> Yeah, but usually those 8 bits represent a value that you raise to the
    > >> power 2.2 to get luminance. When you work that out, 8 bits is a heck
    > >> of a dynamic range.

    >
    > > The classic counterexample is shooting weddings, and trying to get detail in
    > > both the bride's white dress and the groom's black tux.

    >
    > But that's not really a counterexample: there's no way that the ratio
    > of tux/dress exceeds the dynamic range of a JPEG encoded at gamma 2.2.
    > The limiting factor is still sensor noise.


    You sound like you know more about it than I do, but I do know weddings can
    stress most cameras, and usually you have to underexpose digitals so that the
    highlights aren't blown.

    > > From what I've read, most digital cameras give you the range of
    > > slide film, but print film still gives more latitude.

    >
    > >> From what I can see, digital sensors (or at least those in DSLRs)
    > >> have more dynamic range than transparencies but less than print
    > >> film. It may be that with a drum scanner you can squeeze a bit
    > >> more out of a transparency.

    >
    > > I believe in general you only get that extended range in DSLRs when
    > > you use raw mode, which for many cameras can give you 10-12 bits of
    > > precision.

    >
    > What raw gives you is linear encoding, at least with CCDs. That gives
    > you an opportunity to use curves somehow to squeeze that huge dynamic
    > range into that of a print -- which has Dmax 1.2 if you're lucky.
    >
    > > I suspect within 5 years or so, there will be a shift to using
    > > 16-bit formats in cameras.


    I was just speculating that if you go past 8 bits of precision, the next format
    is 16 bits -- even if you only have 12 bits worth of precision from the camera.

    > Actively cooled sensors, maybe?


    Perhaps.

    --
    Michael Meissner
    email:
    http://www.the-meissners.org
     
    Michael Meissner, Jul 28, 2004
    #9
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