On Thu, May 21, 2009 at 10:51 PM, Matthew Miller <[email protected]> wrote: > On Thu, May 21, 2009 at 07:10:28PM -0600, William Robb wrote: >> >> The difference between 1/180th and 1/250th flash synch is substantial >> >> when shooting a brightly backlit subject in bright daylight. >> > A lot can happen in 0.0016 seconds. >> C'est what? > > For example, someone walking by at a brisk pace of 4mph will move an > additional tenth of an inch. With a 1/250th sync, you could have caught them > moving only 0.3 inches, but noooo, with Pentax's horrible 1/180th, we're > stuck with a whole 0.4 inches of movement. > > Of course, with hummingbirds, it's even worse. Why, at 1/180th, the > hummingbird's wings have gone through a whole 38% of a stroke. With 1/250th, > that'd be reduced to a mere 28%. > > Okay, seriously -- the time difference just doesn't seem that much. (1/643 > of a second *different*.) Neither does half a stop. I accept that there's > some narrow cases where it'd help, but I can't see it as the huge deal that > it seems to be to some folks. What am I missing? > > > -- > Matthew Miller [email protected] <http://mattdm.org/>
A half-stop is a huge deal when shooting outdoor with fill flash from a speedlight. You need that extra half-stop of aperture to cover up for the lack of power from the speedlight (vs the sun). It's one reason why the 6MP Nikon consumer bodies found their way into so many pro's bags, as they offered true sync speeds to 1/500 (or max shutter with non-dedicated flash) and High speed sync costs far too much power to be really useful outdoors. Frankly, a 1/4000 max shutter with 1/250 sync would have been a better compromise than 1/8000 and 1/180. -- 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.
