A&P Stupid newb flash question

Discussion in 'Lifestyle' started by Creator, Jun 5, 2008.

  1. Creator

    Creator The Creator Has a Master Plan

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    I'm pretty much guessing when I shoot with my flashes. I have a decent idea what power I should set my 580EX to, and a decent idea what my shutter/iso/apperature should be and then do a few tests and generally get it. But it's all guess work. I dont really understand the concept of aperture with a flash. I understand power and look at it that way - 1/1 is full power and then we go down from there. Cool. Lights too harsh, k ill bring it down.

    I'm kind of confused about my vivitar 285 though - the settings on the wheel... I dont have it in front of me but f stop numbers right? Sooo which is 'highest' and which is 'lowest' in terms of power of the light?

    Also -- the general rule is meter for the background then bring it two stops down and bring in the flash. Do i just set the flash to the f stop I metered to and adjust from there if needed?

    I just need to ramble about off camera flash for a minute i thikn. I'm pretty much happy with my results but I want to get it down so I dont have to fuss around when people are actually paying me.
     
    Last edited: Jun 5, 2008
  2. ( * )( * )

    ( * )( * ) OT Supporter

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    Buy a light meter.
     
  3. Creator

    Creator The Creator Has a Master Plan

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    Meh. From what ive read you can do without. I just want to get my technique down better
     
  4. Jcolman

    Jcolman OT Supporter

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    Aperture controls how much of the light hits your sensor. Think of it as another form of "dialing down the power". In an all ambient light shot, a combination of shutter speed and aperture controls the total exposure. When you use a flash, you can use your shutter speed dial to control your ambient light. Since a flash puts out light at well over 1/10000 second, your shutter speed won't affect the duration of the strobe light like it will ambient, or continuous light.

    The easiest way to set your flash exposure (without a meter or ETTL) is to put a white towel or other white non reflective object in the shot. Take a picture. Chimp the histogram. The ideal exposure will have the towel spiking the histogram just off the right side or slightly over. If the exposure is slightly over, and assuming you have your camera set to show you burned out highlights, the white towel will barely be blinking.

    If non of this makes sense, read up on how to use a histogram. The histogram is a visual representation of your total exposure and is a very valuable tool.
     
  5. Tonster MBA

    Tonster MBA OT'r of the Year 2013 OT Supporter

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    *zoooommmmm*


    thats the sound of that comment going right over my head :hsd:
     
  6. xenon supra

    xenon supra OT Supporter

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  7. Tonster MBA

    Tonster MBA OT'r of the Year 2013 OT Supporter

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  8. OlafBeserka

    OlafBeserka girls pee pee when they see me OT Supporter

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    good tip about the towel. going to try that next time.
     
  9. Jcolman

    Jcolman OT Supporter

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    Thank Chuck Gardner over on FM forums. He has a whole tutorial about exposing with a white towel.
     
  10. twinturboteddy

    twinturboteddy Bling Bling!

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    Loosely thinkg of everything in these terms when using flash

    Shutterspeed = controls ambient light because it is continuous

    Aperature = controls flash power because it is amount of light entering at a split of a second
     

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