It's a combination of the shutter speed, the SR system and also the flash burn speed nowadays.
SR apparently costs sync speed, the high-end Sony's do 1/250 with SSS off and 1/200 with it on. Likely Pentax and Olympus are limiting their sync similarly. Flash burn speed also matters, but only if you are using a hybrid shutter like most of the 6MP Nikons where the physical shutter never exceeds sync speed and the sensor has an electronic shutter to get higher speeds. All the 1/500 sync Nikons did this, but could actually sync at all speeds. They were limited to 1/500 as over that speed you ran into the problem of the flash burn duration exceeding the time the shutter was open, costing an unpredictable amount of exposure (Max flash burn is around 1/1000 of a second on all modern speedlights) I suspect Pentax's new flashes are doing something interesting to get the 1/250 sync. Maybe two capacitors doublepopping the flash at full power? Or even dual tubes. -Adam On Sat, Sep 11, 2010 at 9:25 AM, P. J. Alling <[email protected]> wrote: > That's what I would have thought as well. > > On 9/11/2010 5:06 AM, mike wilson wrote: >> >> Thibouille wrote: >>> >>> I like that, personally. >>> Of importance IMO, new flashes begin 2011 allowing 1/250 sync speed, >>> 18 AF points, speed optimized AF-C, 8fps, 1080p, 200-12800iso, >>> extended 50-25600iso. >>> >>> http://k-rumors.com/new-pentax-k-5-leaked-by-lenstip/ >> >> Surely it's the shutter that determines sync speed, unless some electronic >> mendacity is involved? >> > > > -- > "His lack of education is more than compensated for by his keenly developed > moral bankruptcy." > -Woody Allen > > > -- > 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. > -- M. Adam Maas http://www.mawz.ca Explorations of the City Around Us. -- 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.
