https://community.usa.canon.com/t5/Speedlite-Flashes/Determination-of-power-in-manual-mode-for-600EX-RT/m-p/178796#M3062 <P>Also is it possible to determine the power required in manual&nbsp; mode if we dail distance and fstop value in speedlite 600Ex-RT for correct exposure without using light meter.</P> Sat, 09 Jul 2016 11:34:09 GMT Sanjaydesai 2016-07-09T11:34:09Z https://community.usa.canon.com/t5/Speedlite-Flashes/Determination-of-power-in-manual-mode-for-600EX-RT/m-p/178796#M3062 <P>Also is it possible to determine the power required in manual&nbsp; mode if we dail distance and fstop value in speedlite 600Ex-RT for correct exposure without using light meter.</P> Sat, 09 Jul 2016 11:34:09 GMT https://community.usa.canon.com/t5/Speedlite-Flashes/Determination-of-power-in-manual-mode-for-600EX-RT/m-p/178796#M3062 Sanjaydesai 2016-07-09T11:34:09Z https://community.usa.canon.com/t5/Speedlite-Flashes/Determination-of-power-in-manual-mode-for-600EX-RT/m-p/178973#M3063 <P>You are missing something in your determination. The reflectivity of the subject. While you might get perfect exposures of a grey card, it might not be what you want.</P> Mon, 11 Jul 2016 13:21:27 GMT https://community.usa.canon.com/t5/Speedlite-Flashes/Determination-of-power-in-manual-mode-for-600EX-RT/m-p/178973#M3063 kvbarkley 2016-07-11T13:21:27Z