Originally posted by GoldenWreckedAngle It was shot at 1/320 with flash. Teach me how to do that with my Pentax and I'll kiss ya!
I put the flash on High-Speed Synch, shutter at 1/400s and aimed at the fastest moving object in the room - a rotating ceiling fan at normal operating speed.
Getting late, I'll have to post the photos tommorow.
Here's what I can see :-
Does HSS produce multiple images of fast moving objects ?
Strictly as a matter of electronics, the answer is "Yes" because that's how HSS functions.
As a matter of practical photography ? The fast moving fan blades come out showing motion blur - not surprising at 1/400s. I can't see multiple sharp images, which would have been ugly. You can print it on A4-size, view it on full screen, still OK.
I've used at various times
a. High shutter speed with High-Speed Synch to deliberately darken the ambient background. It works fine with common photography situations (except high speed objects, where you get motion blur).
b. Rear-curtain synch to get the "blurred motion" effect ending with a final sharp flash image.
The limits to the Pentax flash are known, and have rarely bothered me as a "problem".
I believe you are looking for high-shutter speed together with a single flash strobe (just like normal X-synch).
I respect your requirements, I think the conclusion is the Pentax camera/flash won't do it.