UW Photography - High Speed Sync with Ikelite 160 Strobes?

[wedding photographer]

Is there a way to use High Speed Sync with Ikelite 160 Strobes? I would like to go higher than the shutter speed of 200....
Thanks!

[OldClicker]

That depends on the flash duration of the strobes. They would need to be 'on' for something like 1/500 - 1/800 sec. - Terry

[wedding photographer]

Most flashes have the ability to perform high speed sync. You just hit a button and you can go higher than 1/200... Is there an option like these with the Ikelite Strobes..?

[cozmocha]

I doubt it. It's because the rear curtain covers the sensor before the front curtain is off the sensor. So when you shoot at a faster shutter the dark section at the bottom of the frame is the rear curtain showing. The 'sync speed' of a body is the fastest it can go so that the front and rear are clear of the sensor at one point.

High speed sync systems pulse MANY flashes in an exposure so that this wont happen. I do not think that flash can do that.

[OldClicker]

Most flashes have the ability to perform high speed sync. You just hit a button and you can go higher than 1/200... Is there an option like these with the Ikelite Strobes..?

HSS is a propriatory feature for each brand which means that you need that brand of flash to do it. Some 3rd party flash makers (like Metz) may have a model that works. I have never heard of a portrait strobe that does. - Terry

[cozmocha]

Some strobes can do it using the Pocket Wizard HyperSync system. It's even more efficient then the canon HSS system.

http://www.pocketwizard.com/inspirat...ersync_fpsync/

[Loupey]

...High speed sync systems pulse MANY flashes in an exposure so that this wont happen. I do not think that flash can do that.

I believe that most/all high speed sync strobes work by LENGTHENING the single flash duration to the X-sync. So if the flash duration becomes 1/200s, all faster shutter speeds can easily fire within this window.

The longer output produces less intensity and this is why flash range diminishes when HSS is used.

[cozmocha]

http://www.rpphoto.com/howto/view.asp?articleID=1026

Recall that in "standard" flash mode, the flash output is a very brief pulse, usually much shorter than the shutter speed. As flash engineers worked on ways to produce ever-faster stroboscope flash modes (many pulses per second for stop motion sequences or disco dancing), they realized they could pulse the flash thousands of times per second to produce an essentially continuous beam of light (for brief periods).

So in high speed sync mode, the flash fires continuously, many thousands of times per second. All these pulses of light essentially merge together into one long "pulse" that stays on the entire time the shutter is open. This is a lot of work for the flash to do; but it only has to do it for very short periods of time (i.e., less than the standard sync speed, such as 1/200 sec or less).

So in high speed sync mode, the flash stays "on" for the entire time that the shutter is traveling across the frame. There's no longer a problem with parts of the frame blacking out behind the shutter curtains as they sweep across the frame. Now you can use fill flash at shutter speeds of 1/8,000 second!

It's pulsing so fast it might seem like a single flash but it isn't. Plus HSS kills battery life so I try not to use it if I can.

[Loupey]

Interesting.

I wonder what the output of the flash does during this sequence. Does the flash actually cycle completely to the off state? If so, one should see uneven banding (even very narrow ones) as the shutter travels across the focal plane.

Or does the output resemble a low amplitude/high frequency sine wave about a modified guide-number without ever going to zero?

My curiosity is piqued - will have to do some experiments. But I can say that HSS is the second best thing since sliced bread.

Well maybe the 4th best thing - first sliced bread, then digital photography, then internal stabilization, THEN HSS

[OldClicker]

I believe that most/all high speed sync strobes work by LENGTHENING the single flash duration to the X-sync. So if the flash duration becomes 1/200s, all faster shutter speeds can easily fire within this window.

The longer output produces less intensity and this is why flash range diminishes when HSS is used.

As cozmocha says, HSS works like you said but by multiple pulses.

The Pocket Wizard HyperSync seems to be a whole different animal. There are two modes:

- The first optimizes the timing of the flash to maximize the regular sync speed of the camera. Apparently, as the shutter speed is increased past what the manufacturer calls the sync speed, both curtains are still open for a few steps, but not at the same time as the flash fires and not at the same time as a other shutter speeds. HyperSync allows you to reset this timing to get the fastest speed that your camera can actually sync at and (maybe) all the speeds between this max and the spec sync speed.

- The other mode fires the flash before the shutter opens and then uses the long ‘tail’ of the flash during the entire time that the slit is moving across the sensor. This method can be used all the way up to the max shutter speed of the camera. Of course, light is lost since it is only using the ‘tail’.

Of course it also does all the normal flash TTL stuff – very interesting device. Too bad (or very good considering budget ) they don’t make one for Sony.

Terry

[OldClicker]

Interesting.

I wonder what the output of the flash does during this sequence. Does the flash actually cycle completely to the off state? If so, one should see uneven banding (even very narrow ones) as the shutter travels across the focal plane.

Or does the output resemble a low amplitude/high frequency sine wave about a modified guide-number without ever going to zero?

My curiosity is piqued - will have to do some experiments. But I can say that HSS is the second best thing since sliced bread.

Well maybe the 4th best thing - first sliced bread, then digital photography, then internal stabilization, THEN HSS

Here are some scope traces.

http://www.bobatkins.com/photography...peed_sync.html

Terry

[wedding photographer]

The only problem that I won't be able to use the Pocket Wizard HyperSync underwater....