On 13 Mar 2002 at 14:54, Peifer, William [OCDUS] wrote: > > I guess the way to test Tom V's idea (about the possibility that the flash > intensity is calculated from distance and guide number information, but not > controlled by an actual TTL sensor reading)
I backed away from that...;) I'm wondering if distance info is used at all in TTL flash discharge, and if so, how. > is to fire a test shot with and > without the lens cap in place. If the TTL sensor doesn't matter, then the flash > intensities for both of these test shots should be about the same, and the > recycle times should be about the same. If the sensor really ~is~ metering and > controlling flash output, then the lens-cap-in-place test shot should have a > ~much~ longer recycle time. The test I have in mind involves testing A vs. FA lenses (I'm assuming A lenses have no distance info). tv - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
