Flash vs. Ambient light...

Discussion in 'Digital Photography' started by David, Sep 10, 2007.

  1. David

    David Guest

    I often shoot indoors in the evening using aperture-priority mode, opening
    the aperture until the shutter speed is fast enough to avoid camera shake.
    I realize a tripod or faster lens can help out here.

    A few weeks ago I learned that I can use Manual mode to choose any shutter
    speed and aperture opening and the flash seems to compensate to shoot a
    picture that is properly exposed.

    Someone told me that in aperture-priority mode the flash is used for fill
    but in manual mode it is used for primary lighting (not in those exact words
    but that's what I remember, please re-explain using the correct nomenclature
    if you can). When using flash white balance wouldn't one desire that the
    flash light the scene? Why/when would ambient lighting be preferred over
    flash?

    Pointers to sites/books that might help me understand better would be
    appreciated.

    Thanks,

    Dave
    David, Sep 10, 2007
    #1
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  2. David

    dj_nme Guest

    David wrote:
    > I often shoot indoors in the evening using aperture-priority mode, opening
    > the aperture until the shutter speed is fast enough to avoid camera shake.
    > I realize a tripod or faster lens can help out here.
    >
    > A few weeks ago I learned that I can use Manual mode to choose any shutter
    > speed and aperture opening and the flash seems to compensate to shoot a
    > picture that is properly exposed.


    That should only work if you press the AE or green button to get a meter
    reading, otherwise there is nothing to tell the camera how to expose or
    flash unit how to fire.

    > Someone told me that in aperture-priority mode the flash is used for fill
    > but in manual mode it is used for primary lighting (not in those exact words
    > but that's what I remember, please re-explain using the correct nomenclature
    > if you can).


    This sounds like it would only be true if your accessory flashgun is
    attached and turned on or the camera's pop-up flash is in the up/on
    position, otherwise there would be no reason for the flash to fire in
    the first place.

    > When using flash white balance wouldn't one desire that the
    > flash light the scene? Why/when would ambient lighting be preferred over
    > flash?


    Flash (assuming that it's only used for fill) may not match the colour
    balance of the main lighting, ie: the main ambient lighting is tungsten
    (which is redish/yellowish) and the flash (white/bluish) create two
    areas of different colour temperature in your image that can't be
    balanced out by the camera's WB setting or in your editing program.
    There are at least two possible ways around this:
    1)Use your flash to be the primary lighting for the pictures, setting
    your camera's WB to "flash" and overwhelm the ambient lighting with the
    flash.
    2)Put a colour correction filter over the flashgun so that the light
    coming out of it matches the ambient lighting and then using a WB to match.

    > Pointers to sites/books that might help me understand better would be
    > appreciated.
    >
    > Thanks,
    >
    > Dave
    >
    >
    dj_nme, Sep 10, 2007
    #2
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  3. David

    Paul Furman Guest

    David wrote:
    > I often shoot indoors in the evening using aperture-priority mode, opening
    > the aperture until the shutter speed is fast enough to avoid camera shake.
    > I realize a tripod or faster lens can help out here.
    >
    > A few weeks ago I learned that I can use Manual mode to choose any shutter
    > speed and aperture opening and the flash seems to compensate to shoot a
    > picture that is properly exposed.
    >
    > Someone told me that in aperture-priority mode the flash is used for fill
    > but in manual mode it is used for primary lighting (not in those exact words
    > but that's what I remember, please re-explain using the correct nomenclature
    > if you can). When using flash white balance wouldn't one desire that the
    > flash light the scene? Why/when would ambient lighting be preferred over
    > flash?


    WB is an issue but apart from that, ambient light just looks more
    natural for lighting things beyond the range of the flash and avoiding
    shadows. See if your camera has the ability to turn down the flash so
    that the ambient light can be the primary light and flash provides fill.
    That will look best (WB aside).


    > Pointers to sites/books that might help me understand better would be
    > appreciated.
    Paul Furman, Sep 10, 2007
    #3
  4. In article <>,
    "David" <> wrote:

    > I often shoot indoors in the evening using aperture-priority mode, opening
    > the aperture until the shutter speed is fast enough to avoid camera shake.
    > I realize a tripod or faster lens can help out here.
    >
    > A few weeks ago I learned that I can use Manual mode to choose any shutter
    > speed and aperture opening and the flash seems to compensate to shoot a
    > picture that is properly exposed.
    >
    > Someone told me that in aperture-priority mode the flash is used for fill
    > but in manual mode it is used for primary lighting (not in those exact words
    > but that's what I remember, please re-explain using the correct nomenclature
    > if you can). When using flash white balance wouldn't one desire that the
    > flash light the scene? Why/when would ambient lighting be preferred over
    > flash?
    >
    > Pointers to sites/books that might help me understand better would be
    > appreciated.
    >
    > Thanks,
    >
    > Dave


    The flash power can be used to decide how much of the background is
    visible. For example, when I took photos of a friend's wedding I used
    an aperture of F1.4 with no flash. The background was blurred yet it
    was still overwhelmed with clutter and distractions. The pro
    photographer used a high power flash at close range so that the
    background was completely black.

    If the background is very beautiful, meter the exposure from the
    background and use fill flash to make the foreground just as bright.
    For example, taking photos of people with a sunset in the background.
    Kevin McMurtrie, Sep 10, 2007
    #4
  5. David

    David Guest

    "Kevin McMurtrie" <> wrote in message
    news:-sjc.supernews.net...
    > In article <>,
    > "David" <> wrote:
    >
    >> I often shoot indoors in the evening using aperture-priority mode,
    >> opening
    >> the aperture until the shutter speed is fast enough to avoid camera
    >> shake.
    >> I realize a tripod or faster lens can help out here.
    >>
    >> A few weeks ago I learned that I can use Manual mode to choose any
    >> shutter
    >> speed and aperture opening and the flash seems to compensate to shoot a
    >> picture that is properly exposed.
    >>
    >> Someone told me that in aperture-priority mode the flash is used for fill
    >> but in manual mode it is used for primary lighting (not in those exact
    >> words
    >> but that's what I remember, please re-explain using the correct
    >> nomenclature
    >> if you can). When using flash white balance wouldn't one desire that the
    >> flash light the scene? Why/when would ambient lighting be preferred over
    >> flash?
    >>
    >> Pointers to sites/books that might help me understand better would be
    >> appreciated.
    >>
    >> Thanks,
    >>
    >> Dave

    >
    > The flash power can be used to decide how much of the background is
    > visible. For example, when I took photos of a friend's wedding I used
    > an aperture of F1.4 with no flash. The background was blurred yet it
    > was still overwhelmed with clutter and distractions. The pro
    > photographer used a high power flash at close range so that the
    > background was completely black.
    >
    > If the background is very beautiful, meter the exposure from the
    > background and use fill flash to make the foreground just as bright.
    > For example, taking photos of people with a sunset in the background.
    >


    Doesn't metering look at the amount of light in the scene to determine the
    shutter/aperture or in the case of manual mode the amount of flash required
    to expose the scene correctly?

    You said meter from the background- what if the background is brighter than
    the foreground, wouldn't metering the background cause the foreground to be
    overexposed?
    David, Sep 10, 2007
    #5
  6. David

    David Guest

    "Paul Furman" <> wrote in message
    news:yJ1Fi.53221$...
    > David wrote:
    >> I often shoot indoors in the evening using aperture-priority mode,
    >> opening the aperture until the shutter speed is fast enough to avoid
    >> camera shake. I realize a tripod or faster lens can help out here.
    >>
    >> A few weeks ago I learned that I can use Manual mode to choose any
    >> shutter speed and aperture opening and the flash seems to compensate to
    >> shoot a picture that is properly exposed.
    >>
    >> Someone told me that in aperture-priority mode the flash is used for fill
    >> but in manual mode it is used for primary lighting (not in those exact
    >> words but that's what I remember, please re-explain using the correct
    >> nomenclature if you can). When using flash white balance wouldn't one
    >> desire that the flash light the scene? Why/when would ambient lighting
    >> be preferred over flash?

    >
    > WB is an issue but apart from that, ambient light just looks more natural
    > for lighting things beyond the range of the flash and avoiding shadows.
    > See if your camera has the ability to turn down the flash so that the
    > ambient light can be the primary light and flash provides fill. That will
    > look best (WB aside).
    >


    I think my camera (EOS350D) provides fill flash in Tv and Av modes and
    primary lighting in M mode- if anyone knows for sure please verify or
    correct me.

    I have been using the manual mode b/c indoors the lighting is so dim that my
    flash (430EX) usually overpowers the tungsten in the first place and even
    with the flash, when I'm shooting in Av mode I usually end up kicking the
    ISO up to 1600 and the shutter speed is still so slow that I need a tripod
    and pictures of living things end up blurred.


    >
    >> Pointers to sites/books that might help me understand better would be
    >> appreciated.

    >
    David, Sep 10, 2007
    #6
  7. David

    David Guest

    "Kevin McMurtrie" <> wrote in message
    news:-sjc.supernews.net...
    > In article <>,
    > "David" <> wrote:
    >
    >> I often shoot indoors in the evening using aperture-priority mode,
    >> opening
    >> the aperture until the shutter speed is fast enough to avoid camera
    >> shake.
    >> I realize a tripod or faster lens can help out here.
    >>
    >> A few weeks ago I learned that I can use Manual mode to choose any
    >> shutter
    >> speed and aperture opening and the flash seems to compensate to shoot a
    >> picture that is properly exposed.
    >>
    >> Someone told me that in aperture-priority mode the flash is used for fill
    >> but in manual mode it is used for primary lighting (not in those exact
    >> words
    >> but that's what I remember, please re-explain using the correct
    >> nomenclature
    >> if you can). When using flash white balance wouldn't one desire that the
    >> flash light the scene? Why/when would ambient lighting be preferred over
    >> flash?
    >>
    >> Pointers to sites/books that might help me understand better would be
    >> appreciated.
    >>
    >> Thanks,
    >>
    >> Dave

    >
    > The flash power can be used to decide how much of the background is
    > visible. For example, when I took photos of a friend's wedding I used
    > an aperture of F1.4 with no flash. The background was blurred yet it
    > was still overwhelmed with clutter and distractions. The pro
    > photographer used a high power flash at close range so that the
    > background was completely black.
    >
    > If the background is very beautiful, meter the exposure from the
    > background and use fill flash to make the foreground just as bright.
    > For example, taking photos of people with a sunset in the background.
    >


    Also, I thought the higher powered flash simply allowed for flash coverage
    at greater distances... I can hardly tell a difference between using my
    camera's built in flash and the external flash (EOS350D/430EX) aside from
    the fact that the external flash can be used for bounce and I use a diffuser
    with it. I would guess a fast shutter speed would be best for obtaining a
    dark background but I'm not sure what aperture would be preferable in that
    case?
    David, Sep 10, 2007
    #7
  8. David

    Gino Guest

    Have a read through here. Fantastic article is you are using Canon.
    http://photonotes.org/articles/eos-flash/


    "David" <> wrote in message
    news:...
    >I often shoot indoors in the evening using aperture-priority mode, opening
    >the aperture until the shutter speed is fast enough to avoid camera shake.
    >I realize a tripod or faster lens can help out here.
    >
    > A few weeks ago I learned that I can use Manual mode to choose any shutter
    > speed and aperture opening and the flash seems to compensate to shoot a
    > picture that is properly exposed.
    >
    > Someone told me that in aperture-priority mode the flash is used for fill
    > but in manual mode it is used for primary lighting (not in those exact
    > words but that's what I remember, please re-explain using the correct
    > nomenclature if you can). When using flash white balance wouldn't one
    > desire that the flash light the scene? Why/when would ambient lighting be
    > preferred over flash?
    >
    > Pointers to sites/books that might help me understand better would be
    > appreciated.
    >
    > Thanks,
    >
    > Dave
    >
    >
    Gino, Sep 10, 2007
    #8
  9. I will make one suggestion. Try it and see what works well for your
    camera, your typical subjects and the way you use your camera.

    There can not be ONE right answer to a question like this. The right
    one is the one that works for you. What works best for me, may well not be
    very good for you.

    --
    Joseph Meehan

    Dia 's Muire duit


    "David" <> wrote in message
    news:...
    >I often shoot indoors in the evening using aperture-priority mode, opening
    >the aperture until the shutter speed is fast enough to avoid camera shake.
    >I realize a tripod or faster lens can help out here.
    >
    > A few weeks ago I learned that I can use Manual mode to choose any shutter
    > speed and aperture opening and the flash seems to compensate to shoot a
    > picture that is properly exposed.
    >
    > Someone told me that in aperture-priority mode the flash is used for fill
    > but in manual mode it is used for primary lighting (not in those exact
    > words but that's what I remember, please re-explain using the correct
    > nomenclature if you can). When using flash white balance wouldn't one
    > desire that the flash light the scene? Why/when would ambient lighting be
    > preferred over flash?
    >
    > Pointers to sites/books that might help me understand better would be
    > appreciated.
    >
    > Thanks,
    >
    > Dave
    >
    >
    Joseph Meehan, Sep 11, 2007
    #9
  10. In article <>,
    "David" <> wrote:

    > "Kevin McMurtrie" <> wrote in message
    > news:-sjc.supernews.net...
    > > In article <>,
    > > "David" <> wrote:
    > >
    > >> I often shoot indoors in the evening using aperture-priority mode,
    > >> opening
    > >> the aperture until the shutter speed is fast enough to avoid camera
    > >> shake.
    > >> I realize a tripod or faster lens can help out here.
    > >>
    > >> A few weeks ago I learned that I can use Manual mode to choose any
    > >> shutter
    > >> speed and aperture opening and the flash seems to compensate to shoot a
    > >> picture that is properly exposed.
    > >>
    > >> Someone told me that in aperture-priority mode the flash is used for fill
    > >> but in manual mode it is used for primary lighting (not in those exact
    > >> words
    > >> but that's what I remember, please re-explain using the correct
    > >> nomenclature
    > >> if you can). When using flash white balance wouldn't one desire that the
    > >> flash light the scene? Why/when would ambient lighting be preferred over
    > >> flash?
    > >>
    > >> Pointers to sites/books that might help me understand better would be
    > >> appreciated.
    > >>
    > >> Thanks,
    > >>
    > >> Dave

    > >
    > > The flash power can be used to decide how much of the background is
    > > visible. For example, when I took photos of a friend's wedding I used
    > > an aperture of F1.4 with no flash. The background was blurred yet it
    > > was still overwhelmed with clutter and distractions. The pro
    > > photographer used a high power flash at close range so that the
    > > background was completely black.
    > >
    > > If the background is very beautiful, meter the exposure from the
    > > background and use fill flash to make the foreground just as bright.
    > > For example, taking photos of people with a sunset in the background.
    > >

    >
    > Also, I thought the higher powered flash simply allowed for flash coverage
    > at greater distances... I can hardly tell a difference between using my
    > camera's built in flash and the external flash (EOS350D/430EX) aside from
    > the fact that the external flash can be used for bounce and I use a diffuser
    > with it. I would guess a fast shutter speed would be best for obtaining a
    > dark background but I'm not sure what aperture would be preferable in that
    > case?


    Darken the background by diffusing your flash and getting close. You'll
    need to manually set a high flash power in some way. By default the
    camera will mix ambient and flash light.
    Kevin McMurtrie, Sep 12, 2007
    #10
  11. David

    David Guest

    "Gino" <> wrote in message
    news:...
    > Have a read through here. Fantastic article is you are using Canon.
    > http://photonotes.org/articles/eos-flash/
    >


    Thank you for the link, this is a great resource. I am confused on
    switching between Av, Tv, and M modes though for the following reasons...

    The paper states "Canon EOS cameras always default to fill flash mode when
    the camera is in Tv, Av and M modes,"
    (http://photonotes.org/articles/eos-flash/index2.html#fillflash).

    I just took two pictures under my desk (rather dark) with the 350D and
    430EX.

    The first was in M mode 1/125 s, f/5.6, ISO 100. The shot looks to be
    exposed properly.

    The second was in Av mode f/5.6, ISO 100. The camera chose a shutter speed
    of 15 s. The shot is a bit brighter than the previous.

    From the sound of the flash recharging I could tell that neither used the
    flash at full power.

    Why did the camera choose 15 s in Av mode when in M mode 1/125 s was
    sufficient. It seems to me that the M mode shot was not operating in "fill
    flash" mode like the website stated.

    I am still working on getting through this part but the answer didn't
    immediately jump out at me
    http://photonotes.org/articles/eos-flash/index2.html#confusion.

    I wish that the exif data contained two more pieces of information:
    1. If the flash was operating as "fill flash" or "regular flash."
    2. What flash power level was used.
    David, Dec 3, 2007
    #11
  12. David

    Ali Guest

    "David" <> wrote in message
    news:...

    >> Have a read through here. Fantastic article is you are using Canon.
    >> http://photonotes.org/articles/eos-flash/


    > I just took two pictures under my desk (rather dark) with the 350D and
    > 430EX.
    >
    > The first was in M mode 1/125 s, f/5.6, ISO 100. The shot looks to be
    > exposed properly.
    >
    > The second was in Av mode f/5.6, ISO 100. The camera chose a shutter
    > speed of 15 s. The shot is a bit brighter than the previous.


    LOL. 15 seconds of exposure compared to 1/125, well of course it will be a
    bit brighter. What were you using to meter?
    Ali, Dec 3, 2007
    #12
  13. David

    Douglas Guest

    "David" <> wrote in message
    news:...

    >
    > Why did the camera choose 15 s in Av mode when in M mode 1/125 s was
    > sufficient. It seems to me that the M mode shot was not operating in
    > "fill flash" mode like the website stated.
    >
    > I am still working on getting through this part but the answer didn't
    > immediately jump out at me
    > http://photonotes.org/articles/eos-flash/index2.html#confusion.
    >
    > I wish that the exif data contained two more pieces of information:
    > 1. If the flash was operating as "fill flash" or "regular flash."
    > 2. What flash power level was used.
    >
    >

    For correct use of fill flash you should set the flash to "high-speed" mode
    and the camera to either program mode or Aperture priority (Av mode)

    For aperture priority mode you will always get the camera deciding exposure
    based on ambient light. You can set a custom function for 1/250th shutter
    speed in Av mode but the camera will still meter for ambient light if the
    ambient exposure requires a higher shutter speed.

    The only really successful way to use a Canon speedlite on an EOS camera is
    in full manual mode and let the flash decide on the level of light to emit.
    I know this sounds a little odd but truly, The ETTL part is an accurate
    metering method only when it suits the conditions.

    If you then use the camera set to (for example) F/5.8 with a shutter speed
    of 1/125th or more, You will get acceptable pictures most of the time.

    I now use a Nikon speedlite on my Canon EOS. I use the flash in full auto
    mode (measures its own exposure requirements) for all indoor shots with the
    camera in manual mode. Outdoors I still use the EX 580 Canon flash for fill
    flash.

    I've read a lot about these flashes and none of it made sense to me until I
    worked on the presumption Canon speedlites work as fill flash nearly all the
    time. The only way to get their power output is to switch to 100% manual.
    Had I realized the limitations of a Canon speedlite, I'd never have parted
    with my Metz stuff.

    Douglas
    Douglas, Dec 3, 2007
    #13
  14. "David" <> wrote:
    >"Gino" <> wrote in message
    >news:...
    >> Have a read through here. Fantastic article is you are using Canon.
    >> http://photonotes.org/articles/eos-flash/
    >>

    >
    >Thank you for the link, this is a great resource. I am confused on
    >switching between Av, Tv, and M modes though for the following reasons...
    >
    >The paper states "Canon EOS cameras always default to fill flash mode when
    >the camera is in Tv, Av and M modes,"
    >(http://photonotes.org/articles/eos-flash/index2.html#fillflash).
    >
    >I just took two pictures under my desk (rather dark) with the 350D and
    >430EX.
    >
    >The first was in M mode 1/125 s, f/5.6, ISO 100. The shot looks to be
    >exposed properly.


    Okay, so this image is taken with you forcing 1/125 and
    f/5.6, which apparently happens to be about 11 fstops
    under exposed!

    How do we know it is 11 stops underexposed? Because
    when you let the camera meter it and set the shutter
    speed according the the meter, it used 15 seconds, which
    is about 11 stops more light.

    Okay, so, the camera exposure is obviously set so low
    that ambient light had virtually nothing to do with the
    image you recorded! Instead, the flash fired and
    provided what it thinks is enough light to give you a
    proper exposure with an aperture of f/5.6.

    Note that since the area under your desk is probably
    fairly small, and probably has a good bit of reflective
    areas to bounce light off of, and since your 430EX has a
    lot of extra power... it actually required only a
    relatively small amount of power (maybe 1/8 or less) to
    give enough light. As a result your flash recharged
    very quickly and clearly had not fully discharged when
    it fired.

    >The second was in Av mode f/5.6, ISO 100. The camera chose a shutter speed
    >of 15 s. The shot is a bit brighter than the previous.


    In this case, the camera metered approximately what it
    determined to be necessary, and set the shutter speed
    accordingly. That would probably have given you a
    correct exposure. But since the flash was enabled for
    fill mode, it fired too. The problem is that since
    there was already enough light, and this is a very small
    area with good reflective surfaces to bounce light
    around, the flash over exposed it simply because it
    cannot provide less than 1/64th of full power, and that
    was too much!

    So this exposure is a bit over exposed.

    >From the sound of the flash recharging I could tell that neither used the
    >flash at full power.


    Yep, it probably didn't take much at all.

    >Why did the camera choose 15 s in Av mode when in M mode 1/125 s was
    >sufficient.


    Because 1/125 wasn't anything close to sufficient! It
    had exactly one endearing sufficiency, and that was that
    it opened up the shutter long enough for the flash to
    light up the night for you!

    But make no mistake, the flash is what determined the
    exposure, not the camera's shutter speed.

    >It seems to me that the M mode shot was not operating in "fill
    >flash" mode like the website stated.


    Well, it's just that "fill" in the case of no light at
    all amounts to 100% of what is required! Danged
    automatic devices are like that... :)

    >I am still working on getting through this part but the answer didn't
    >immediately jump out at me
    >http://photonotes.org/articles/eos-flash/index2.html#confusion.
    >
    >I wish that the exif data contained two more pieces of information:
    > 1. If the flash was operating as "fill flash" or "regular flash."
    > 2. What flash power level was used.


    Some flash units do communicate with the camera more
    than others, though I don't know if any of them for a
    Canon will provide that information.

    --
    Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
    Ukpeagvik (Barrow, Alaska)
    Floyd L. Davidson, Dec 3, 2007
    #14
  15. David

    Scott W Guest

    David wrote:
    > "Gino" <> wrote in message
    > news:...
    >> Have a read through here. Fantastic article is you are using Canon.
    >> http://photonotes.org/articles/eos-flash/
    >>

    >
    > Thank you for the link, this is a great resource. I am confused on
    > switching between Av, Tv, and M modes though for the following reasons...
    >
    > The paper states "Canon EOS cameras always default to fill flash mode when
    > the camera is in Tv, Av and M modes,"
    > (http://photonotes.org/articles/eos-flash/index2.html#fillflash).
    >
    > I just took two pictures under my desk (rather dark) with the 350D and
    > 430EX.
    >
    > The first was in M mode 1/125 s, f/5.6, ISO 100. The shot looks to be
    > exposed properly.
    >
    > The second was in Av mode f/5.6, ISO 100. The camera chose a shutter speed
    > of 15 s. The shot is a bit brighter than the previous.
    >
    > From the sound of the flash recharging I could tell that neither used the
    > flash at full power.
    >
    > Why did the camera choose 15 s in Av mode when in M mode 1/125 s was
    > sufficient. It seems to me that the M mode shot was not operating in "fill
    > flash" mode like the website stated.
    >
    > I am still working on getting through this part but the answer didn't
    > immediately jump out at me
    > http://photonotes.org/articles/eos-flash/index2.html#confusion.
    >
    > I wish that the exif data contained two more pieces of information:
    > 1. If the flash was operating as "fill flash" or "regular flash."
    > 2. What flash power level was used.
    >
    >
    >


    I almost always have the camera in manual mode when using the flash.
    You can see how much the ambient light will count for the exposure by
    looking at the display that shows over under exposure, if I have a
    bright background I will set this for at about 0, not over or under
    exposed. Then I choose much much flash power to use, if I am filling I
    often use -1 EV to -2 EV, I don't like the look of a lot of flash fill.

    If it is pretty dark and I am just trying to get a feel for the
    background in the shot I might shoot at between -1 EV to - EV for the
    ambient part and shoot with normal amount of flash power.

    Play around with adjusting the ambient light part and the flash part,
    you have good control of both and are free to mix and match about
    whatever ratio you might want.

    Many people use too much flash power when doing a fill, it can look
    pretty unnatural.

    Scott
    Scott W, Dec 3, 2007
    #15
  16. David

    David Guest

    "Ali" <> wrote in message
    news:_2_4j.795$...
    >
    > "David" <> wrote in message
    > news:...
    >
    >>> Have a read through here. Fantastic article is you are using Canon.
    >>> http://photonotes.org/articles/eos-flash/

    >
    >> I just took two pictures under my desk (rather dark) with the 350D and
    >> 430EX.
    >>
    >> The first was in M mode 1/125 s, f/5.6, ISO 100. The shot looks to be
    >> exposed properly.
    >>
    >> The second was in Av mode f/5.6, ISO 100. The camera chose a shutter
    >> speed of 15 s. The shot is a bit brighter than the previous.

    >
    > LOL. 15 seconds of exposure compared to 1/125, well of course it will be
    > a bit brighter. What were you using to meter?
    >


    Literally, it was just a *bit* brighter.

    I aimed the camera at the same spot as I had with the first shot- is that
    what you were asking by what I was using to meter?
    David, Dec 4, 2007
    #16
  17. David

    David Guest

    "Douglas" <> wrote in message
    news:fj1tnu$lok$...
    >
    > "David" <> wrote in message
    > news:...
    >
    >>
    >> Why did the camera choose 15 s in Av mode when in M mode 1/125 s was
    >> sufficient. It seems to me that the M mode shot was not operating in
    >> "fill flash" mode like the website stated.
    >>
    >> I am still working on getting through this part but the answer didn't
    >> immediately jump out at me
    >> http://photonotes.org/articles/eos-flash/index2.html#confusion.
    >>
    >> I wish that the exif data contained two more pieces of information:
    >> 1. If the flash was operating as "fill flash" or "regular flash."
    >> 2. What flash power level was used.
    >>
    >>

    > For correct use of fill flash you should set the flash to "high-speed"
    > mode and the camera to either program mode or Aperture priority (Av mode)
    >
    > For aperture priority mode you will always get the camera deciding
    > exposure based on ambient light. You can set a custom function for 1/250th
    > shutter speed in Av mode but the camera will still meter for ambient light
    > if the ambient exposure requires a higher shutter speed.
    >

    Thanks Douglas,

    When you say "the camera will still meter for ambient light" do you mean
    that the camera will calculate flash power such that the flash will be used
    in place of ambient light? I'm hung up a bit on the terminology.

    > The only really successful way to use a Canon speedlite on an EOS camera
    > is in full manual mode and let the flash decide on the level of light to
    > emit. I know this sounds a little odd but truly, The ETTL part is an
    > accurate metering method only when it suits the conditions.
    >


    I just did a bit of research on ETTL. If I understand correctly, it fires a
    pre-flash and the camera uses the pre-flash image to meter. I'm confused
    though. This is what I read:
    http://photo.net/bboard/q-and-a-fetch-msg?msg_id=0006Wn. It says that the
    metering system will adjust the "real" flash duration. Yet on this page:
    http://www.dpreview.com/learn/?/key=metering, metering is defined as
    measuring the light and calculating the proper exposure. I thought exposure
    was the combination of shutter speed, aperture, and ISO level. Does the
    metering system calculate flash power as well as the other factors?

    Also, do I have a choice to use modes other than ETTL with a Canon speedlite
    on an EOS camera? If I read correctly, the flash decides on the level of
    light to emit during manual mode only (this sounds different than what I was
    reading in the EOS flash tutorial)? Is the flash not using ETTL?

    > If you then use the camera set to (for example) F/5.8 with a shutter speed
    > of 1/125th or more, You will get acceptable pictures most of the time.
    >
    > I now use a Nikon speedlite on my Canon EOS. I use the flash in full auto
    > mode (measures its own exposure requirements) for all indoor shots with
    > the camera in manual mode. Outdoors I still use the EX 580 Canon flash
    > for fill flash.
    >
    > I've read a lot about these flashes and none of it made sense to me until
    > I worked on the presumption Canon speedlites work as fill flash nearly all
    > the time. The only way to get their power output is to switch to 100%
    > manual. Had I realized the limitations of a Canon speedlite, I'd never
    > have parted with my Metz stuff.
    >
    > Douglas
    >


    Do the Canon speedlites ever work as fill flash in manual mode? How would I
    know if it was not working as fill flash in other modes?

    David
    David, Dec 4, 2007
    #17
  18. David

    David Guest

    >
    >>Why did the camera choose 15 s in Av mode when in M mode 1/125 s was
    >>sufficient.

    >
    > Because 1/125 wasn't anything close to sufficient! It
    > had exactly one endearing sufficiency, and that was that
    > it opened up the shutter long enough for the flash to
    > light up the night for you!
    >


    Forgive me for being dense but I don't understand why 1/125 s wasn't
    sufficient. In M mode it worked out great when the flash fired.

    I feel like I almost understand what's going on here but I'm still one step
    away.

    >
    >>It seems to me that the M mode shot was not operating in "fill
    >>flash" mode like the website stated.

    >
    > Well, it's just that "fill" in the case of no light at
    > all amounts to 100% of what is required! Danged
    > automatic devices are like that... :)


    But in Av mode there was the same amount of light present.

    David
    David, Dec 4, 2007
    #18
  19. David

    David Guest

    "Scott W" <> wrote in message
    news:47549067$0$2525$...
    >
    > I almost always have the camera in manual mode when using the flash.
    > You can see how much the ambient light will count for the exposure by
    > looking at the display that shows over under exposure, if I have a bright
    > background I will set this for at about 0, not over or under exposed.
    > Then I choose much much flash power to use, if I am filling I often use -1
    > EV to -2 EV, I don't like the look of a lot of flash fill.
    >
    > If it is pretty dark and I am just trying to get a feel for the background
    > in the shot I might shoot at between -1 EV to - EV for the ambient part
    > and shoot with normal amount of flash power.
    >
    > Play around with adjusting the ambient light part and the flash part, you
    > have good control of both and are free to mix and match about whatever
    > ratio you might want.


    When in manual mode how to I adjust the ambient light part and the flash
    part?

    I know how to change flash exposure comensation, if that's what you are
    refering to with the EV values ??

    I am uncertain how to specify differences between ambient and flash though
    (I'm using the Rebel XT, perhaps I don't have as much control here?)

    Thanks,

    David



    >
    > Many people use too much flash power when doing a fill, it can look pretty
    > unnatural.
    >
    > Scott
    >
    David, Dec 4, 2007
    #19
  20. David

    Douglas Guest

    "David" <> wrote in message
    news:...
    >
    > "Douglas" <> wrote in message
    > news:fj1tnu$lok$...
    >>
    >> "David" <> wrote in message
    >> news:...
    >>
    >>>
    >>> Why did the camera choose 15 s in Av mode when in M mode 1/125 s was
    >>> sufficient. It seems to me that the M mode shot was not operating in
    >>> "fill flash" mode like the website stated.
    >>>
    >>> I am still working on getting through this part but the answer didn't
    >>> immediately jump out at me
    >>> http://photonotes.org/articles/eos-flash/index2.html#confusion.
    >>>
    >>> I wish that the exif data contained two more pieces of information:
    >>> 1. If the flash was operating as "fill flash" or "regular flash."
    >>> 2. What flash power level was used.
    >>>
    >>>

    >> For correct use of fill flash you should set the flash to "high-speed"
    >> mode and the camera to either program mode or Aperture priority (Av mode)
    >>
    >> For aperture priority mode you will always get the camera deciding
    >> exposure based on ambient light. You can set a custom function for
    >> 1/250th shutter speed in Av mode but the camera will still meter for
    >> ambient light if the ambient exposure requires a higher shutter speed.
    >>

    > Thanks Douglas,
    >
    > When you say "the camera will still meter for ambient light" do you mean
    > that the camera will calculate flash power such that the flash will be
    > used in place of ambient light? I'm hung up a bit on the terminology.
    >
    >> The only really successful way to use a Canon speedlite on an EOS camera
    >> is in full manual mode and let the flash decide on the level of light to
    >> emit. I know this sounds a little odd but truly, The ETTL part is an
    >> accurate metering method only when it suits the conditions.
    >>

    >
    > I just did a bit of research on ETTL. If I understand correctly, it fires
    > a pre-flash and the camera uses the pre-flash image to meter. I'm
    > confused though. This is what I read:
    > http://photo.net/bboard/q-and-a-fetch-msg?msg_id=0006Wn. It says that the
    > metering system will adjust the "real" flash duration. Yet on this page:
    > http://www.dpreview.com/learn/?/key=metering, metering is defined as
    > measuring the light and calculating the proper exposure. I thought
    > exposure was the combination of shutter speed, aperture, and ISO level.
    > Does the metering system calculate flash power as well as the other
    > factors?
    >
    > Also, do I have a choice to use modes other than ETTL with a Canon
    > speedlite on an EOS camera? If I read correctly, the flash decides on the
    > level of light to emit during manual mode only (this sounds different than
    > what I was reading in the EOS flash tutorial)? Is the flash not using
    > ETTL?
    >
    >> If you then use the camera set to (for example) F/5.8 with a shutter
    >> speed of 1/125th or more, You will get acceptable pictures most of the
    >> time.
    >>
    >> I now use a Nikon speedlite on my Canon EOS. I use the flash in full auto
    >> mode (measures its own exposure requirements) for all indoor shots with
    >> the camera in manual mode. Outdoors I still use the EX 580 Canon flash
    >> for fill flash.
    >>
    >> I've read a lot about these flashes and none of it made sense to me until
    >> I worked on the presumption Canon speedlites work as fill flash nearly
    >> all the time. The only way to get their power output is to switch to 100%
    >> manual. Had I realized the limitations of a Canon speedlite, I'd never
    >> have parted with my Metz stuff.
    >>
    >> Douglas
    >>

    >
    > Do the Canon speedlites ever work as fill flash in manual mode? How would
    > I know if it was not working as fill flash in other modes?
    >
    > David


    The concept of fill flash is to provide just enough light to remove black
    eyes and show detail in the shadows but not so much as to dull the
    background. The custom function to set shutter speed at 1/250th in Av mode
    basically forces the minimum exposure to be whatever aperture you choose at
    1/250th second.

    When this would cause under exposure, the speedlite is supposed to power up
    enough to provide correct exposure. This will only work on the closest
    object if you have another custom function (use multi point or area
    averaging mode in ETTL) set to multi point. You get better results in area
    average.

    I'm not entirely sure if the flash metering works ETTL or not on AUTO mode
    when you set the camera to manual. I do know the Nikon speedlite I now use
    only works in "AUTO" mode because the ETTL is not compatible with Canon's.
    The exposures are more correct with the Nikon flash than the Canon.

    Douglas
    Douglas, Dec 4, 2007
    #20
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