On Jul 2, 2010, at 13:53 , John Sessoms wrote:
The K-10D and K-20D both allow you to set the on-board flash to
trailing curtain sync. How difficult would it be for them to make
the hot-shoe also fire on the trailing curtain when a non-dedicated
"flash" is installed?
E.G. like with a radio-sync transmitter or Vivitar 285HV? Dedicated
flash like the AF-540FGZ has its own circuitry to talk to the camera
and can be set to trailing curtain sync.
Is this something they could do with a firmware update?
Or is it something that would require radical hardware revision?
For that matter what do the dedicated pins on the Pentax shoe tell
the flash? I know what the big one in the center does, and it's
obvious which one is ground.
Everything you need to know except the actual format and content of
the "digital" signal and the "mode" format.
http://kmp.bdimitrov.de/technology/hot-shoe/index.html
Here's a diagram of a circuit to isolate an old high voltage flash
from the hot shoe about half way down the page. I know, you didn't
ask, but, it can't hurt to have a copy on your hard drive!
http://www.flickr.com/groups/strobist/discuss/72157607929201242/
And the Hot Shoe and 5P cable pins, in case you wanted to know. Near
bottom of page.
http://forums.dpreview.com/forums/read.asp?forum=1036&message=28607959
Lots and lots of data about the Pentax AFxxxFGZ flashes compared to
others manufacturers.
http://knol.google.com/k/pentax-p-ttl-hot-shoe-flash-comparison#
also a more technical tome:
http://www.jr-worldwi.de/photo/index.html?ist_DS_internalflash.html
Joseph McAllister
[email protected]
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Grant me the senility to forget the people
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The good fortune to run into the ones I do, and
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