help with flash at night

leiftvleiftv Registered Users Posts: 219 Major grins
edited August 4, 2007 in Technique
How should I set up my flash (580ex-ii) and camera (rebel xti) to shoot outside at night. I want to be able to see thae background in the photos not just illuminating the subject?

Comments

  • LiquidAirLiquidAir Registered Users Posts: 1,751 Major grins
    edited August 4, 2007
    leiftv wrote:
    How should I set up my flash (580ex-ii) and camera (rebel xti) to shoot outside at night. I want to be able to see thae background in the photos not just illuminating the subject?

    It depends a lot on what kind of environment you are working in. The light from your flash falls off as the square of the distance from your flash. Say your subject is 2 meters (about 6 feet) from the camera if the backround is

    2.8 meters away the light will be 1 stop darker
    4 meters away the light will be 2 stops darker
    5.6 meters = 3 stops
    8 meters = 4 stops
    11 meters = 5 stops

    and so forth. Note that you can read the sequence of numbers right off your aperture dial.

    So then, what do you do?

    Sometimes you bounce off a wall or a ceiling. Bouncing scatters the light more broadly in the room and often puts more light on the background relative to your subject.

    Sometimes you can use a second flash for the background triggered remotely.

    Sometimes you can stand further from your subject and use a telephoto.

    Sometimes the right answer is to use multiple remote flahses and light the entire space rather than specifically lighting the subject. Three or four flashes distributed strategically can sometimes give you reasonably even light over a large area. This is often the best (but also most expensive) option if you are shooting candids.


    There is no one answer to this problem. You really have think independantly about your subject and background light and come up with a solution to the problem at hand.
  • pathfinderpathfinder Super Moderators Posts: 14,703 moderator
    edited August 4, 2007
    If you put your 580ex in ETL II, and your camera in Av mode, your image will be illuminated by the flash properly for the subject in the foreground, and the background will be correctly exposed by the ambient light.

    BE AWARE - that if the background is poorly lit, the exposure may be VERY long - as in seconds to minutes... Hence, you may need a tripod for this frequently. If the sun has not set, you can shoot handheld in Av mode - just watch your shutter speed.

    As LiquidAir stated, there is no free lunch - and no strobe/camera that can master all exposure problems without an informed and understanding operator.

    http://photonotes.org/articles/eos-flash/
    http://photonotes.org/articles/eos-flash/index2.html
    http://photonotes.org/articles/eos-flash/index3.html

    The BEST source of information about the use of the 580ex and the EOS camera system..

    A good spot for learning to use any strobe is [url]www.http://www.strobist.blogspot.com/[/url]

    Learning to understand and use the Canon flash system can produce spectacular results...... especially in bright sunshine.

    175882651-L.jpg

    More of my flash images can be seen here
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
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