Fill Flash with the Canon 20D?

Discussion in 'Canon' started by Jerry Shaw, Dec 2, 2004.

  1. Jerry Shaw

    Jerry Shaw Guest

    I have a new Canon 20D and 580 EX flash. I'm looking for information on using
    this combination for fill flash.

    I grab a lot of non-professional (meaning stark amateur) photographs of people
    in costumes at conventions (anime and SF conventions, if you must know).
    Usually, the photos are outside, usually in the sun. The photos are not posed,
    beyond just asking the model if I can take their picture. This gives me a lot
    of harsh shadows, as you can imagine, as I can't really control the angle of
    the sun relative to the model.

    My previous camera was a Sony 717. I added a Vivitar 285 flash. With this
    combination, I could set the automatic flash and the aperture for a flash fill
    of about 2/3 stop under, just to soften the shadows. It seemed to work pretty
    well when I also underexposed the picture by 2/3 stop also.

    The Canon 20D and 580 EX flash combination has two exposure compensations, one
    for the AE and one for the flash. The manual mentions fill flash, but doesn't
    really go into the settings needed for this. I suspect there is some
    combination of the settings, (possibly using manual for the exposure, possibly
    using aperture priority), that will allow me to not worry about adjusting the
    settings for every shot.

    I'm looking for settings that I can use to point at a subject in the shadow,
    then in harsh sunlight, and get good enough photos, but with automatic flash
    fill when needed.

    Anyone done any flash fill, and have any suggested settings for the Canon 20D?


    (Sorry about the cross-post, but Earthlink doesn't have the newsgroup yet, so please post to
    Jerry Shaw, Dec 2, 2004
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  2. Your equipment is a generation newer than mine but I'll offer that program
    mode and Av mode will both provide what you want.
    Charles Schuler, Dec 2, 2004
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  3. Jerry Shaw

    Mark B. Guest

    Program mode will assume the flash is the only source of light for the
    subject and adjust aperture, shutter speed, and flash output accordingly.
    Av will assume flash will light the subject, but adjust shutter speed for
    background ambient light. So I'd say they could be very different depending
    on ambient light conditions.

    Mark B., Dec 3, 2004
  4. Jerry Shaw

    Skip M Guest

    Actually, ETTL does that in program mode, too...
    Skip M, Dec 4, 2004
  5. Jerry Shaw

    Todd H. Guest

    Howdy Jerry,

    The definition of fill flash varies based on lighting condition and
    ISO. Really, what we're talking about is playing with the mixture of
    flash light to ambient light, and in a fill flash situation, the
    desire is to have mostly ambient light, and just a taste of flash to
    punch in the shadows.

    One way to guarantee a given amount of ambient light with just a taste
    of fill flash is to use Tv modes. Pick a shutterspeed that gives you
    the level of ambient light that looks right, and let the camera fill
    in the rest for proper expsoure. Warning though, your max flash sync
    speed can get in the way here on the top end.

    Another way is to use P mode and vary the ISO setting. Higher ISOs
    should give you more of an available light mix, lower isos will call
    in more flash to make the exposure.

    Yet another way is to play with exposure compensation. An old trick
    to get more available light and less flash is to go +1 stop on the
    main exposure compensation, and -1 stop on the flash exposure

    I'm not sure there's any one setting that'll work best regardless of
    the situation. Try P mode on ISO 200 for starters, and tweak from

    Best Regards,
    Todd H., Dec 15, 2004
  6. Jerry Shaw

    Jerry Shaw Guest


    My original reason for the post was to get some fill flash on outdoor shots,
    to fill in the harsher shadows at a convention I was going to. It was cold
    enough outside that day that there wasn't anyone outside.

    I used a bit of fill on the stage presentations, however (and thereby hangs a
    The Canon 20D will sync at up to 1/250. The 580EX has a high-speed flash mode,
    that lets the camera know it can shoot above that speed. I set the flash for
    that mode, but I don't think I ever used a speed above 1/250. Maybe if I were
    outside, I could have used it at 1/1000 or so. Maybe during this Christmas
    break, I can get a chance to go to Venice Beach, and photograph some of the
    bodybuilders there. That should give me a good chance to test out the higher
    speeds in the bright sun.
    I made the mistake of using the P mode on the stage pictures I took. The
    camera set the speed to 1/60 (with ISO 800) even with the minimal lighting on
    the small stage. I had the flash set at -2/3 a stop. The problem I had was
    that the contestants were moving quite a bit. And even with the low lighting,
    the camera still exposed the stage light pretty well, but exposed the
    costumers with the flash. This caused a lot of blurring. Next time, I will go
    to full manual and set the speed to 1/125 or 1/200, and let the flash do most
    of the work.

    Another thing I found out fairly quickly was to not turn on the "safety"
    parameter in the camera, as it will change the speed of the Tv mode when there
    is not enough light, even if you want the flash to do all the job. With this
    setting on, the camera will reduce the speed of the shutter, overriding the Tv
    setting. I got a few several second shots this way, when I really wanted to
    use 1/250 and the flash for the light.
    On the 20D, the camera will attempt to set the speed and F ratio to expose the
    background properly (in all modes except manual), even if you have the flash
    on. It will then use the flash to expose the subject in the center properly.
    So, it is usually better to go -2/3 or -1 on the camera, then +1 or so on the
    flash, to fill the subject properly.

    Supposedly, the Canon has an auto-fill when the flash is on that will drop the
    flash power in lighter scenes, to just a fill level. That is why I need to
    take a lot of outdoor shots and determine the best fill settings in sunlight.
    I may go up into the mountains in the forest, to get some harsh shadows to try
    the best settings.
    With P mode and flash, at any ISO, the shutter speed is limited to 1/60 to
    1/250, and the aperture is adjusted accordingly. So I'll probably use a fixed
    Tv mode, at 1/1000 or so to stop the action, then use the highspeed flash mode
    for fill. I may even set the camera in full manual, exposing for the sun, then
    using the flash for fill. That's probably the way I'll go when I go to the
    next Muscle Beach competition, as the sun is usually bright all day.
    Thanks for the information,
    Jerry Shaw, Dec 16, 2004
  7. Anyone done any flash fill, and have any suggested settings for the
    In my experience, the best way to get fill flash to work right is to
    use a manual flash. The manual flash also opens up lots of new
    possibilities, and at $70 doesn't even cost much.

    Dr. Joel M. Hoffman, Dec 17, 2004
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