Outdoor flash

Discussion in 'Medium Format' started by bill_heiker, May 19, 2003.

  1. It has always been my understanding that when doing outdoor fill
    flash, you meter the scene and then set the flash for 1 to 2 stops
    less output. In other words, if you meter the scene at f8 and 1/125,
    then by setting the flash at f5.6 or f4, the shadows should fill
    nicely, but not completely. Well, I tried this today. The camera
    indicated an ambient exposure of F11 and 1/250 second. With that as
    a starting point, I took pictures with flash settings from f5.6 up to
    f22 in one stop increments. When the processed prints came back,
    every print was EXACTLY the same, both the foreground and the
    background was exposed the same in all pictures. In every picture,
    the foreground (a picture of me) was overexposed while the background
    (a house across the street) was correctly exposed. The flash works
    just fine with my indoor shots and the lab that does my processing
    tells me that my negatives are consistently properly exposed. Does
    anyone have any idea what is the problem with my efforts to do
    outdoor fill flash?
     
  2. You didn`t tell what shutter speed you used.You will need to meter the exposure at the same shutter speed as you flash syc. speed to get the correct exposure.Example if you meter at F8 at 125 sec and shoot at F8 and 60th of a second you are getting more ambient light on your shot.
    I shoot with a hassey that way I can use flash at all shutter speeds outside.I meter ambient light and then take a flash reading. If I get F8 at 250 0f a second I set the flash for F8 and shoot at 250 of a second. If you want more fill then set the flash for F16 etc.
     
  3. Russell, yes, I did keep the shutter speed consistent. All shots were done at 1/250.
     
  4. How were you metering the flash? If you were using some
    kind of auto setting, are you sure the flash had enough
    power? If you're shooting a person against a distant background,
    that background will soak up a lot of light, and my guess is
    that the flash was putting out all of its available power on
    every shot.
    <p>
    With a small nearby subject against a distant background, it's
    usually most reliable to switch the flash to manual. Either
    meter it with a flash meter or use the calculator on the
    back of the flash (or the GN method if the flash lacks any
    sort of calculator).
     
  5. are reasoning in the reverse order?

    "meter the scene and then set the flash for 1 to 2 stops less output. In other words, if you meter the scene at f8 and 1/125, then by setting the flash at f5.6 or f4"--> f11 or f16?
     
  6. Bill,

    Your methodology should work perfectly if you are metering with a handheld flash
    meter.

    If the ambient exposure is 1/125 @ f8 and your flash meter reads f4 or f5.6 when
    you pop the flash, your fill flash will not be overpowering.

    I have had little luck using this technique with automatic flash. I have also on
    occasion had problems using this technique with advanced TTL Flash.

    But you know, it ALWAYS works when using my handheld flash meter.

    Don't forget to balance the color temperature of your flash with your ambient color
    temperature. Nothing screams fill flash louder than a subject lit by blue colored
    strobe light.
     
  7. You really should repeat your experiment on slide film. On print film the exposure lattitude is too large, and combined with what a printer may correct you'll hardly be able to tell exposure differences.
     
  8. the poto shop balanced the shots for you so they would come out.. some good equipment does this automatically.. almost all cameras are auto exposed from in camera meter which is only correct in few situations, so negs have a wide latitude to make ametures happy.. use slide film for this kind of tests.and tell developer not to do any adjusting and to use new or properly updated chemicals. .. when using one flash ( i use ambinet light for fill when in shade or clowdy days) measure the light at the subject about one stop over ambient light. if using two flashes use one flash to one side a little over ambient, other side one stop over, third flash would be on back ground one stop over.. then take reading at subeject with all flashes going.. and shoot that.. a good flash meter is more accurate than your cammera so if problems arise i would suspect the camera before the metering.. a great flash for this type of work in ameture setups is a viviter 283 with a vp-1 varipower attachment.. its adjustable in very light amounts of flash, not several settings like most flashes. i use a luna star f gossen meter..and its available used... its awsome.. good luck dave..
     
  9. Bill you sound confused.How did you alter the flashes output?Was this all done on AUTO?Were you shooting in bright sun and trying to fill those shadows?Without seeing your film & prints,it is hard to say,but it sounds like you fired way too much flash over exposing the subject.The lab should always try to print for the flesh,not the background.(find another lab)Often outdoor flash shots exposed this way will have correct skin exposure,but the background will look like a nuclear bomb is exploding.
     
  10. The first issue is to do this test with transparency film, as suggested. I suspect there is some auto-correction being done by the lab. Alternately, ask for a contact sheet, rather than proof prints from print film, and that cuts out that problem. You could take the negs to a lab and get contacts from the roll you shot, and you might learn more.

    The other issue is whether you are using auto flash of some sort. The flash should be set for manual, so that you can regulate the output consistently. If ambient was f:11 and the flash is set on manual, and the flash is set for an exposure of f:5.6 at the flash-to-subject distance you were using for the film speed you were using, then you should see a very slight fill effect, if any effect at all. The f:8 setting should give you something more natural; f:11 should look like obvious fill flash; and f:16 and f:22 (if the flash is powerful enough to produce that much output at the distance and film speed indicated) will look overexposed. You should also do an exposure with the flash off, just to see the difference between no fill and the minimal fill setting.
     
  11. I note some people are mentioning lab auto corrections. Note on careful reading that Bill describes taking every shot with the camera set at 1/250@f/11. All he's trying to change is the flash power. If the flash power is indeed changing, the ratio between flash and ambient will change, and regardless of auto lab compensation, the photos will look somewhat different, as the light balance changes between foreground and background.
    That's why I'm guessing that the flash power didn't really change. And the most likely reason I can think of for that is an auto flash running out of power and dumping full output on each shot.
     
  12. Try altering the light ratio by changing the apeture, or the distance from the flash to the foreground subject.

    Try using the flash in overcast weather, as the main or modelling light - away from the camera.
     
  13. Due to the inherent fall-off in light with distance with flash, you will not get a good result with a light subject in the forground, unless you use additional flash or bounce to light up the background.

    Try a coloured model, with a white house as background.

    The purpose of fill-flash in bright sunlight is to reduce contrast by filling shadows - so the foreground test subject should be three-dimentional, with shadows to fill, not a 2d picture.
     
  14. Bill

    While I do not disagree with the method you have chosen, (i.e. meter the scene and set the flash for 1 or two stops less than ambient exposure) I disagree that this is the only method. I have had fantastic success in using my flash as the main light and the ambient light as the fill light in outdoor portraiture. You will need an accurate light meter that also measures flash exposure. and you will need to have your flash off camera. try it sometime.

    Kevin
     
  15. This is a superb, well-written thread, guys.
     

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