On Thu, Jul 30, 2009 at 06:05:25PM +0200, Ralf R. Radermacher scripsit: > Graydon <o...@uniserve.com> wrote: > > Are you sure? I think I've seen auto-DFS with a 15s P mode > > exposure. There may well be auto-DFS for all exposures above n > > seconds, where n is around 12. > > Whether the camera does a DFS or not depends on time and ISO. It > doesn't at 30 sec and ISO 100 in M. It does, however, at any time and > ISO setting in B.
Do you have any quantified idea what the cutoff points are? (I could figure them out for the K20D, but that's not really the issue as I understand it.) Somebody might be able to calculate the temperature of concern from that. I think that policy supports my "B could be used to take a really awful picture" theory; at high ISO (= pushing the sensor) and long exposure (= heat builds up), noise is a serious issue without DFS. So somebody at Pentax has enforced DFS for B mode, because the camera doesn't know how long the exposure is going to be in B mode and can't do a calculation. -- Graydon -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
