Originally posted by Digitalis It is a limit that is present in both the hardware and in the software, the shutter curtains will be visible at 1/250th and above.
That is what we are lead to believe, but it difficult to say with certainty that the hardware limit actually occurs at 1/250th because the software won't let us find out. Pentax has chosen to protect us at all costs from those dreaded black bars by disabling the pop-up flash, the hotshoe, and the PC socket at higher-than-sync speeds, so there's no way to send a sync signal. But on Nikon cameras for instance, the PC socket will fire at any speed, and it has been shown that the hardware limit is actually faster than the software limit. The Nikon engineers built a fudge factor into the software, and it may be that Pentax has gone the same route.
But for the sake of argument, lets say that the black bars begin appearing at 1/181st of a second, that still doesn't mean that they will occupy the entire frame at first. David Hobby has some examples of what the bars look like at different speeds in his post about hacking your flash sync speed
Strobist: Hacking Your Camera's Sync Speed, Pt. 2 Unfortunately his techniques don't work on Pentax, but it's interesting to see what would be possible if not for the software imposed limitation. With some creative cropping one could get some very dramatic shots at say 1/500th. I for one would like the choice of whether I need to be protected from myself. A simple custom menu option would suffice. We have "permit aperture ring", why not "permit unsynced flash"?