On Thu, May 21, 2009 at 11:09:00PM -0400, Paul Stenquist wrote: > You're missing the fact that the amount of flash exposure you can work > into a shot is dependent only on the f stop. So if I shoot a backlit > portrait outdoors at f5.6, 1.250th, I can fill flash in at that 5.6 value. > If I'm forced to stop down to f6.7 because I can't go beyond 1/180th in > shutter speed, I lose flash exposure and increase DOF.
But again, *half* a stop. Assuming the FA 77mm at 10 feet, the depth of field is going from about 13" to 15". (Right? Up past my bedtime, so feel free to check my math.) Two (and a half, actually -- rounding) inches isn't nothing, but it's still only two inches. > Ideally, I'd like to have flash synch up to 1/1000th, but that's complex > and cost;y. Right, I understand that going from 0.0056s to 0.0010s would be useful. That's two and a half stops better, and in the example above, you're shooting at f/2.8 and have more than halved your DOF, down to about 6". > And high-speed synch doesn't help much, because the flash power is greatly > diminished by multiple firings. So, improved noise performance should help just as well, right? I wouldn't be surprised at all if the sensor refinements gain you your half stop back right there. Optimistically, more. -- Matthew Miller [email protected] <http://mattdm.org/> The Definitive Pentax P-TTL Flash Model Guide: <http://pttl.mattdm.org/> -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
