High Speed Flash has anyone used it.

[ericmark]

This allows one to use the flash in combination with shutter speeds faster than the camera's sync speed, which in current Pentax models is 1/180th of a second. At shutter speeds exceeding that, there's never actually any time when the entire sensor is exposed at once: there's just a fast-traveling slit between the front and rear shutters. HSS works by creating many very fast pulses rather than one bright flash, so the tradeoff is reduced power. This isn't necessary (in fact, quite the contrary) for freezing motion — for that, you need to look at the actual flash duration (which is generally much, much shorter than the shutter speed).

I have tried taking pictures of a water fall with flash but during the day and the problem was although the flash froze the motion there was also a faint trail caused by natural light. Clearly a night shot would eliminate this problem but so would high speed flash. However since the power is also reduced the question is would it then be powerful enough to light the waterfall or any other fast moving object?

So has anyone used high speed flash and if so how did they find it?

[Marko]

I have used this feature on my flash many times but mostly for portraits - I find it works very well.

I have to ask - was there not enough light so that you could have frozen the waterfall without flash?
Lighting giant things like a waterfall with a small portable flash doesn't seem like it would work out that well. Personally If it's day....I'd just raise the Iso and shoot without flash. Am I missing something here?

[Mad Aussie]

I also can't really see why I'd want to flash a waterfall. Unless perhaps you talking about a very small one or even a manmade one perhaps?

However, I use HSS all the time when shooting birds. My base settings are shutter on 400 or above depending on ambient light and subject movement, ISO 400, f8 if possible, and then the high speed flash. I use the same settings for sports etc as well. I don't think you've ever seen a wildlife photo from me that didn't use similar settings and the flash in this way.

[ericmark]

Yes water fall small man made it was selected as local to test out before I went walking a long distance so I could work out how. But although there are some in Wales out in the open many are surrounded in trees. I find although the Camera will work at ISO 1600 in real terms ISO 800 is maximum without grain and midday that with my lens gave me around 1/350 second which did not really freeze the water. Using two flash guns it did freeze the water but because down to 1/180 second also got faint trails behind each droplet.

The Vivitar 3500 is the only one of my old flash guns which has a low trigger voltage so only one I can use on the hot shoe of my K10D Pentax and it has three modes. Motor drive which gives a reduced output very good for motion freezing, Manual which gives full output takes ages to re-charge, and three outputs linked to the eye on the flash so it I set aperture to suit I get an automatic exposure. The latter has a reasonable recycle time. However the flash gun only has two instead of to-days three contacts so is lacking some of the dedication one normally gets.

Being short of money I can't really afford the new all singing dancing flash but also it would seem daft to get one which latter becomes a door stop so seemed good idea to ask about the special features before getting anything else. So thank you for your replies I now need to consider what to do.