I know many of you don’t like to hear those of us that complain about the slow 1/180 max synch speed of Pentax. Whenever it comes up, many say it shouldn’t matter, and some say, use High Speed Synch.
For me, it's a limitation in my senior portrait photography, and my sports photography. It puts me at a disadvantage because I use Pentax. Rather than me trying to explain it poorly, I'll point to a few examples of people who can explain it better than me.
in the news today:
Strobist: Nikon D600: Think Twice Before You Jump In this one, David Hobby is actually saying that the fact that the new D600 has a flash synch speed of only 1/200 makes the camera a no-go for him.
A very good explanation of why it’s important is here:
Flash Sync Speed
Finally, one of our forum members, Maxfield Photo, gave a good explanation of why HSS is not the answer in most cases (from this thread
https://www.pentaxforums.com/forums/general-photography-industry/198557-any-f...photokina.html)
"Basically max sync speed is the fastest speed at which the shutter is fully open at any one point in time. At speeds above the max sync the second curtain starts to close before the first curtain finishes opening, so what you get in effect is an ever-narrowing slit that moves across the sensor. HSS works by pulsing the flash at a reduced power for the entire time the shutters are in motion (1/180th of a sec in Pentax's case). The problem is the narrower the size of the moving slit, the more light is wasted bouncing off the curtains, and the less light that actually reaches the sensor. HSS can usually be used at normal flash distances up to about 1/1000th, but any faster than that and you'll have to get the flash very close to the subject, or use multiple speedlights as one lightsource (you may have seen the brackets for portable softboxes that acommodate up to four flashes) HSS is great for bringing some saturation back to your skies in outdoor portraits, but contrary to what the name might suggest, it's not good for capturing fast action.
To give you some idea, my Metz 58 has a normal max working distance of 20 meters at f/2.8, ISO 100, at it's maximum zoom setting of 105mm (that's with bare bulb, no modifiers). If I cross over into HSS territory, the working distance immediately drops to
4.8 meters @ 1/250th
4.3 meters @ 1/350th
3.4 meters @ 1/500th
3.0 meters @ 1/750th
and 2.4 meters @ 1/1000th
I could keep going, but you see the distances become really small, and that's without any light modifiers, who wants that? If Pentax would increase the max sync speed, not only would we not have to engage HSS as soon, but because the shutter curtains travel faster at 1/250th, the moving slit would actually be wider at any given shutter speed, allowing more light to reach the sensor, and less to be wasted by bouncing off the curtains - essentially making HSS more efficient.
Another way to solve this problem is to introduce a hybrid shutter. Nikon did this unintentionally with the D70s. The way it works is the shutter opens fully, and then the sensor turns on for the amount of time necessary, let's say 1/1000th of a sec, then the second shutter closes. It's a very simple system, but what it means is, in effect, there is no max sync speed. The shutter is fully open at every shutter speed. This has made the D70s something of a cult favorite among strobists, but for some reason (probably to sell HSS flashes) Nikon stopped producing cameras with hybrid shutters. This is a niche Pentax could really take advantage of, since the D70s was only a 6MP camera, but first they need to re-enable at least the hotshoe or the PC socket above max sync speeds, the pop-up would be nice too for optical slaves."
I really hope that Pentax gives serious consideration to it in the K-3 and/or future cameras.