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<blockquote data-quote="WayneF" data-source="post: 213483" data-attributes="member: 12496">Well, you can use manual flash for fill in bright sun.&nbsp; Just experiment with it a bit, and set the power level as you see is desired for the result that you want.&nbsp; &nbsp; Do experiment enough to see both 'too much' and 'too little&quot;, so you will know the range and the choices.&nbsp; This won't be wasted work.&nbsp; IT WILL BE ABOUT THE SAME NEXT TIME IN SIMILAR SITUATION (it is called experience).&nbsp; &nbsp; Bright sunlight is the same, and you can make your subject distance be the same.Or.. the flash manual should have a guide number chart, with guide numbers for each zoom value.&nbsp; If for example, you are using it at 50mm zoom, use that column.&nbsp; Multiply the chart ISO 100 values by 1.414 to get ISO 200 values your camera is using.&nbsp; Or divide if converting going the other way.&nbsp; Then suppose your camera is using f/16 for subject at 8 feet, which is Guide Number 16x8=GN 128 needed (for f/16 at 8 feet, ISO 200).&nbsp;&nbsp; 128/1.414 = GN 90 in ISO 100 chart.&nbsp; Find that GN 90 (or closest value) in the column for the 50mm zoom you are using, and use that power level... Full or 1/2 power maybe.&nbsp; Pretty simple.However, and here is the thing about it - that is for computing&nbsp; full flash exposure.&nbsp; You only want fill exposure, maybe two stops less than that in bright sun.&nbsp;&nbsp; So instead of 1/2 power indicated, drop two stops to 1/8 power (each half power step is one stop).&nbsp; You can compute 2 stops less fill level by simply dividing this computed GN 90 by 2, to look up power level for GN 45 (which would be fill two stops down).&nbsp; These are the ISO 100 numbers converted to match the power levels in the chart.You can do this evaluation one time before you leave home, and will have a very good starting point to tweak manual flash.&nbsp; You can also practice this in the backyard, before the actual event.&nbsp; &nbsp; If you want to do it, there certainly is a way.</blockquote>

[QUOTE="WayneF, post: 213483, member: 12496"] Well, you can use manual flash for fill in bright sun. Just experiment with it a bit, and set the power level as you see is desired for the result that you want. Do experiment enough to see both 'too much' and 'too little", so you will know the range and the choices. This won't be wasted work. IT WILL BE ABOUT THE SAME NEXT TIME IN SIMILAR SITUATION (it is called experience). Bright sunlight is the same, and you can make your subject distance be the same. Or.. the flash manual should have a guide number chart, with guide numbers for each zoom value. If for example, you are using it at 50mm zoom, use that column. Multiply the chart ISO 100 values by 1.414 to get ISO 200 values your camera is using. Or divide if converting going the other way. Then suppose your camera is using f/16 for subject at 8 feet, which is Guide Number 16x8=GN 128 needed (for f/16 at 8 feet, ISO 200). 128/1.414 = GN 90 in ISO 100 chart. Find that GN 90 (or closest value) in the column for the 50mm zoom you are using, and use that power level... Full or 1/2 power maybe. Pretty simple. However, and here is the thing about it - that is for computing full flash exposure. You only want fill exposure, maybe two stops less than that in bright sun. So instead of 1/2 power indicated, drop two stops to 1/8 power (each half power step is one stop). You can compute 2 stops less fill level by simply dividing this computed GN 90 by 2, to look up power level for GN 45 (which would be fill two stops down). These are the ISO 100 numbers converted to match the power levels in the chart. You can do this evaluation one time before you leave home, and will have a very good starting point to tweak manual flash. You can also practice this in the backyard, before the actual event. If you want to do it, there certainly is a way. [/QUOTE]

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