Happy upgrading to K-1?

If it helps, I have used a Sunpak auto30dx on Pentax DSLRs, up to and including a K5 with no issues. You can check trigger voltages here http://www.botzilla.com/photo/strobeVolts.html#Achiever

Thanks, Autozoom 3000 = 246 volts, so a tiny bit risky! In any event, the film speed dial has got stuck, albeit on 400ASA and I do have the newer Pentax/Samsung 540, but just too many options on that to consider bothering with it out in the field.
Maybe I'll risk dismantling the Sunpack to see if I can free the dial and hope the capacitor is well discharged so I don't end up electrocuting myself! Mind, until Alan put me onto the Hi-speed synch of the 540 I've always considered it a non starter. Even with that though it sounds from the manual a bit hit and miss working the exposure out. Whatever happened to normal TTL flash metering?
To use the old flash on a DSLR I did purchase second hand from someone in the States a Wein SafeSynch (couldn't track one down here) but that sometimes fails to fire the flash, another reason I haven't bothered much with flash. Also given the silly ISO's we can set now it isn't as if we're stuck at 25 or 64 ASA with Kodachrome so black cats in coal cellars are possible without flash.

John, it's well worth exploring HSS using your '540' flash, and I'm sure it won't seem so complex once you start trying it. The exposure control is P-TTL automatic, with the usual flash compensation available, and you're best in manual camera mode to easily control the ambient brightness with shutter speed.

Alans example there is shot in the golden hours, so he didn't need an extreme short exposure ... My seaside ones earlier are in glaring midday light, with high contrast throwing shadows onto the faces, so I needed 1/1000th sec to get the ambient under control. The HSS flash took care of the subjects.

The Pentax flashes really make it all fairly simple, as once you set 'HS' sync mode you can move the shutter speed up and down around the max sync speed without having to switch HS on our off, it's just automatic.

There's help available right here, from me, on the forum There's a section on HSS in my 'Pentax Flash Guide'' (grab a copy from the link below my post here), plus there's a sticky thread at the top of the Flash Photography forum about Practical HSS with photo examples....

Thanks Nigel, I downloaded your flash book so will have a peruse of it.
One thing I have found with the 540 is that it has a habit of jumping out of the hot shoe and it all gets a bit cumbersome when mounted, I used to use the old Sunpack on an extension lead with a sensor in the hot shoe, holding the camera in one hand (you could with an ME) and the Sunpack in the other and it all worked fine and easily. For some reason,, probably to do with the weight of DSLRs and lack of a hot shoe sensor comparable to the Sunpack one, the way I used to do it doesn't work for me nowadays, yet the old method worked every time, if only I could replicate it with what we have now! I just used to set the flash intensity to the distance at the aperture/ASA setting, I was using or let the sensor do its thing and all was well. But that was 30 years ago!
In a bundle of camera bits I purchased I acquired a small Cobra flash (designed for Pentax) which has quite a low trigger voltage, but that only has auto/manual, but the auto will be TTL, not P-TTL. I wonder why normal TTL is so difficult to build into current cameras when they can detect orbits of stars in relation to the earth, Time/date/geolocate stamp photographs, But TTL flash which has been around for years? No.

Its a different metering technology .... P-TTL uses pre-flashes to assess the proximity and reflective properties of the subject, and then the camera pre-determines a fixed flash output power. The older TTL technology uses additional flash sensors near the film plane, so senses reflected light directly from the film and cuts off the flash when enough has been detected.

The fundamental difference therefore is that P-TTL judges the exposure needed before it has occurred, and TTL judges it after it has !

Also, the TTL sensors are not there in Digital SLRs.

Just be careful to push the flash fully into the hotshoe and turn the locking wheel firmly. I usually use my thumb to press against the hotshoe directly to push it fully in. The newer Pentax flashes have a metal plate for the hotshoe, which makes it all seem a lot more solid, however there's more risk that your camera will be damaged if it all falls on the ground.

Am I right in understanding that you have the Samsung branded version of the AF-540 FGZ flash ?

Yes indeed. I've downloaded the Pentax manual as it is more detailed than the provided Samsung version, but even then some things are glossed over as if the person writing it didn't really know themselves! The section on high speed synch is typical of that.

There's certainly a fair bit of interpretation needed when looking for practical help in the flash manuals. The information is correct but often said in an obtuse manner. My Guide' aims to support the Manuals by looking at the various functions in detail, filling in the gaps, but adding the 'why would I need this?' part ....

Hi Nigel. 9:53am on 31 July is Golden Hour. Never knew thanks.

Well you've made it LOOK like golden hour Alan, so take that as a complement