ISO ?? on a digital cam.

Discussion in 'Digital Photography' started by orion, May 21, 2004.

  1. orion

    orion Guest

    Many digitals have ISO selection. I obviously know from SLR's what to
    expect, ie increase the ISO of a film generally equals more noise and
    grain..

    What's the effect of a decent digital of using a higher ISO? Does the
    digital noise increase?, and to what extent, (more or less than film)?
    orion, May 21, 2004
    #1
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  2. orion

    Lionel Guest

    Kibo informs me that "orion" <> stated that:

    > Many digitals have ISO selection. I obviously know from SLR's what to
    >expect, ie increase the ISO of a film generally equals more noise and
    >grain..
    >
    >What's the effect of a decent digital of using a higher ISO?


    It's fairly similar to the same thing with film, although digital noise
    doesn't look the same as heavy grain.

    > Does the
    >digital noise increase?,


    Yes.

    > and to what extent, (more or less than film)?


    Depends on the camera. Digicams tend to be worse than film at higher
    ISO's, & the nicer DSLRs tend to be better.

    --
    W
    . | ,. w , "Some people are alive only because
    \|/ \|/ it is illegal to kill them." Perna condita delenda est
    ---^----^---------------------------------------------------------------
    Lionel, May 21, 2004
    #2
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  3. orion

    Banjopikr1 Guest

    >What's the effect of a decent digital of using a higher ISO? Does the
    >digital noise increase?,


    Depends on the sensor in the camera. CMOS sensors have less noise than the CCD
    sensors. I use ISO 800 frequently on a digital rebel and the noise is almost
    non existent. At ISO 1600, some noise shows, but generally acceptable. The
    newer CCD cameras are much better now.
    Banjopikr1, May 21, 2004
    #3
  4. orion

    DJ Guest

    On Fri, 21 May 2004 08:06:19 GMT, "orion" <> wrote:

    > Many digitals have ISO selection. I obviously know from SLR's what to
    >expect, ie increase the ISO of a film generally equals more noise and
    >grain..
    >
    >What's the effect of a decent digital of using a higher ISO? Does the
    >digital noise increase?, and to what extent, (more or less than film)?
    >


    If you have broadband, here are some large sample files

    ISO100 http://www.splatco.com/david/red_rose.jpg 500K

    ISO1600 http://www.splatco.com/david/a_flower_for_george.jpg 2+MB


    In each case, in IE they will display small and and need to be enlarged: hover
    the mouse and click the button that appear in the lower RH corner.

    Both taken with a Canon 300D.

    The ISO 1600 pic was taken as a dare for the group's resident troll/fruitcake.
    I'd not normally use 1600 ISO on such a subject, but it demonstrates that 1600
    is emminently useable in these cameras.

    Note you would not get anywhere near comparable results with one of the "lesser"
    point and shoot digitals. They use tiny sensors and suffer horrific noise at
    high sensitivities. Just look for some Sony F828 samples to see what I mean.
    DJ, May 21, 2004
    #4
  5. orion

    Ken Anderson Guest

    "DJ" <> wrote
    >
    > In each case, in IE they will display small and and need to be enlarged:

    hover
    > the mouse and click the button that appear in the lower RH corner.
    >
    >

    You can fix that in Tools, Internet Options, Advanced. Scroll down to the
    Multimedia section and uncheck "Enable Automatic Image Resizing."
    Ken Anderson, May 21, 2004
    #5
  6. orion

    Alan Browne Guest

    orion wrote:

    > Many digitals have ISO selection. I obviously know from SLR's what to
    > expect, ie increase the ISO of a film generally equals more noise and
    > grain..
    >
    > What's the effect of a decent digital of using a higher ISO? Does the
    > digital noise increase?, and to what extent, (more or less than film)?


    You've got the right idea. When film spped increases, the grain size
    increases (in x,y if you will). But for digital, the noise increases
    (dynamic) without changing in x,y dimension. Good DSLR's look quite
    noise free until high ISO / high reproduction sizes are made.


    --
    --e-meil: there's no such thing as a FreeLunch.--
    Alan Browne, May 21, 2004
    #6
  7. orion

    Don Guest

    "orion" <> wrote in message
    news:%Lirc.834$...
    > Many digitals have ISO selection. I obviously know from SLR's what to
    > expect, ie increase the ISO of a film generally equals more noise and
    > grain..
    >
    > What's the effect of a decent digital of using a higher ISO? Does the
    > digital noise increase?, and to what extent, (more or less than film)?
    >
    >

    The ISO rating of film is a measure of the film's sensitivity to light. It
    is not a measure of the granularity. The measurement technique takes into
    account the "toe" characteristics of the film, a phenomenon that does not
    exist in CCD or CMOS focal planes. The last I heard the ISO were attempting
    to standardize on a rating for digital systems, but had not yet published a
    draft.

    We are used to relating the ISO rating of a film to its granularity because,
    in fact, they are related through the detective quantum efficiency (DQE) of
    the film, which is relatively stationary from film to film but has improved
    over the years. It's difficult to measure, but in modern B&W films it's in
    the region of 1%-2%, I believe. In color films it's even more difficult to
    measure, and is different for each layer. It's usually taken to be in the
    region of 0.8% to 1.5%, but I don't think anyone is very confident in that.

    While the DQE of CCDs is much higher, as much as 90% in linear B&W arrays,
    there are other noise sources that usually predominate over the photon
    noise. These include leakage current, preamplifier noise, discharge current
    noise, etc.

    The ISO rating of films within a given family is controlled by the grain
    size. For a constant DQE, the granularity goes up with the square root of
    the ISO rating, more or less. The variablity of speed of a CCD is
    controlled by the gain of the preamplifier and A-to-D converter. Because
    the extraneous noise sources predominate over the photon noise, the noise
    goes up more or less proportional to the speed. That's why most digital
    cameras that look good at ISOs of 50-100 seem to fall behind their film
    counterparts at the higher ISO ratings.

    Don
    Don, May 21, 2004
    #7
  8. Lionel <> wrote in message news:<>...

    > It's fairly similar to the same thing with film, although digital noise
    > doesn't look the same as heavy grain.


    This depends on the design. Foveon noise at very high ISOs looks just
    like high ISO film grain so their is basically no penalty from using
    film. Bayer noise is comprised of brilliant multi-colored artifacts
    than make for a real obviously-taken-with-digital mess, see...

    http://www.dpreview.com/reviews/sigmasd10/page13.asp
    George Preddy, May 22, 2004
    #8
  9. orion

    Lionel Guest

    Kibo informs me that (George Preddy) stated
    that:

    >Lionel <> wrote in message news:<>...
    >
    >> It's fairly similar to the same thing with film, although digital noise
    >> doesn't look the same as heavy grain.

    >
    >This depends on the design. Foveon noise at very high ISOs lo[*SLAP!*]


    The SD9 doesn't even *have* high ISO settings.

    We're still waiting to see those photos you lied about selling,
    'George'.

    --
    W
    . | ,. w , "Some people are alive only because
    \|/ \|/ it is illegal to kill them." Perna condita delenda est
    ---^----^---------------------------------------------------------------
    Lionel, May 22, 2004
    #9
  10. "George Preddy" <> wrote in message
    news:...
    > Lionel <> wrote in message

    news:<>...
    >
    > > It's fairly similar to the same thing with film, although digital noise
    > > doesn't look the same as heavy grain.

    >
    > This depends on the design. Foveon noise at very high ISOs looks just
    > like high ISO film grain so their is basically no penalty from using
    > film. Bayer noise is comprised of brilliant multi-colored artifacts
    > than make for a real obviously-taken-with-digital mess, see...
    >

    Similar luminance noise:
    <http://www.dpreview.com/reviews/SigmaSD10/Samples/ISO/lumi_graph.gif>

    Bart
    Bart van der Wolf, May 23, 2004
    #10
  11. On Fri, 21 May 2004 08:06:19 GMT, "orion"
    <> wrote:

    > Many digitals have ISO selection. I obviously know from SLR's what to
    >expect, ie increase the ISO of a film generally equals more noise and
    >grain..
    >
    >What's the effect of a decent digital of using a higher ISO? Does the
    >digital noise increase?, and to what extent, (more or less than film)?
    >


    It tends to be more "spotty" as apposed to chunky/grainy.

    I've never seen a large size print of a colour high ISO film, but
    would like to so I can compare, but in black and white the effect is
    very similar looking, in colour the noise tends to be lots of
    multi-coloured spots/dots.


    --
    Jonathan Wilson.
    www.somethingerotic.com
    Jonathan Wilson, May 25, 2004
    #11
  12. On Fri, 21 May 2004 10:05:20 -0400, "Ken Anderson"
    <> wrote:

    >"DJ" <> wrote
    >>
    >> In each case, in IE they will display small and and need to be enlarged:

    >hover
    >> the mouse and click the button that appear in the lower RH corner.
    >>
    >>

    >You can fix that in Tools, Internet Options, Advanced. Scroll down to the
    >Multimedia section and uncheck "Enable Automatic Image Resizing."
    >


    Thanks for that :)

    Its amazing how long you can use a product, yet never check its full
    options and capabilities!

    --
    Jonathan Wilson.
    www.somethingerotic.com
    Jonathan Wilson, May 25, 2004
    #12
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