A&P Newb flash questions

Discussion in 'Lifestyle' started by Creator, Jun 11, 2008.

  1. Creator

    Creator The Creator Has a Master Plan

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    I tried to ask this before but I didnt phrase it well so trying again.

    The concepts of zoom and fstop on a flash confuses me. Do I meter the background, then go one f.stop down from that, then set the flashes 'f stop' to the original meter?

    So if the room is f 2.8 at 1/250 do I bring it down to f4 at 1/250, then what do i set the flash to? I keep my 580EX on manual. It goes 1/1 1/2 1/4 1/8 1/32, etc etc. How's that translate? Also, when spinning the dial on the power setting it stays on that setting for more than one 'click'. IE i set it to 1/4 but there a few different settings within 1/4. What the heck are those?

    When I throw in a second and third light should I be having the slaves be set at a lower power? How much lower?
     
  2. IntheWorks

    IntheWorks windin film.. takin pics Moderator

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    I don't think the fstop on the flash actually does anything.. I think it's just for reference. and zoom... depends on what you want.
     
  3. jared_IRL

    jared_IRL OT Supporter

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    the zoom on the flash determines the width of the spread on the flash.

    longer zoom lengths are actually tighter beams of light, so the flash can reach further and achieve it's rated strength.

    So the zoom numbers on the flash WILL impact the exposure, but only because of how tight it is.

    the fstop looking numbers are the manual flash power. 1/1 is full power, 1/2 is 1 stop slower, etc.

    The numbers between them are 3rds of a stop of light. if you have it set to 1/4 +0.3, adding .3 stop to the 1/4 power of the flash. It's just reeeaaaaallly detailed incriments of light.

    I'm not sure what look you're trying to achieve with your photos, so I can't tell you how to set the flash after you meter.

    But if I was metering for a room, i'd take my reading, then figure out how many stops of light I want to achieve the aperture and shutter speed on my camera, set the flash to make up the difference, and start from there.
     
    Last edited: Jun 12, 2008
  4. isaac86hatch

    isaac86hatch This thread sucks

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    shutter = ambient

    aperture = flash + ambient

    ISO = both
     
  5. Creator

    Creator The Creator Has a Master Plan

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    Yah I know that I am talking about on the FLASH
     
  6. jared_IRL

    jared_IRL OT Supporter

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    you miss the post above his?
     
  7. NOR*CAL

    NOR*CAL OT Supporter

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    There's a knob on the 285HV.

    I think it's just a reference chart though.
     
  8. jared_IRL

    jared_IRL OT Supporter

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  9. OlafBeserka

    OlafBeserka girls pee pee when they see me OT Supporter

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  10. Creator

    Creator The Creator Has a Master Plan

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    THat got copy pasted into textedit for future reading :bigthumb:
     
  11. IntheWorks

    IntheWorks windin film.. takin pics Moderator

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    They don't have any effect on the output of the flash, it's just a guide number "chart" If you're in full manual set at 1/4 power, adjusting the f/stop isn't going to make any bit of difference. adjusting that f/stop will just tell you at that power setting how many feet away you need to be from your subject to achieve that f/stop out of your flash

    it's all explained here
    http://strobist.blogspot.com/2007/12/guide-number-your-free-flash-meter.html
     
  12. isaac86hatch

    isaac86hatch This thread sucks

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    I don't know if anyone has touch on it yet, both both statements are right. There's a KNOB on the front that adjusts flash power 1/16th, 1/8th, M and so on and then the there is the wheel on the the side that is just for guesstimating the ASA/fstops/shutter.
     

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