Help with 645Z strobe ghosting

paulster · 08-01-2017, 09:00 AM

He's not looking for high-speed sync though. He's actually looking for very short flash duration, which is quite different. Perhaps counter-intuitively high-speed sync requires a long flash pulse (either real or simulated via pulsing) to allow for high shutter speeds. For this kind of work the best solution is a flash with a very short duration as it doesn't have the mechanical limitations of a shutter.

Bob L · 08-01-2017, 09:09 AM

Originally posted by paulster

He's not looking for high-speed sync though. He's actually looking for very short flash duration, which is quite different. ..........

That depends how much the ambient light is contributing to the exposure. A long flash pulse duration and fast shutter speed will negate the influence of the ambient.

BostonUKshooter · 08-01-2017, 09:51 AM

Originally posted by paulster

He's not looking for high-speed sync though. He's actually looking for very short flash duration, which is quite different. Perhaps counter-intuitively high-speed sync requires a long flash pulse (either real or simulated via pulsing) to allow for high shutter speeds. For this kind of work the best solution is a flash with a very short duration as it doesn't have the mechanical limitations of a shutter.

OK thks....good point....Broncolor make a big thing of their very short flash duration on some models, and Karl Taylor emphasises that in his stop-action commercial work....however they are quite pricey!

bfmelton · 08-06-2017, 06:05 PM - **2 Likes**

Update: I just completed a shoot with the rented Einsteins, shooting around 3 or four stops down from maximum. Result:

Hard to tell from this crop, but this girl was completely in the air flying across the studio.

Ghosting problem solved. Now to save up for Einsteins. :-)

Thanks again!

Last edited by bfmelton; 08-06-2017 at 06:21 PM.

Edgar_in_Indy · 08-07-2017, 08:43 AM

I'm glad you got the problem solved. The Einsteins are really special lights.

Just out of curiosity, did you still have motion blur at higher power levels, or did you simply not need to turn them up more for your purposes?

bfmelton · 08-07-2017, 07:17 PM

Originally posted by Edgar_in_Indy

I'm glad you got the problem solved. The Einsteins are really special lights.

Just out of curiosity, did you still have motion blur at higher power levels, or did you simply not need to turn them up more for your purposes?

Compared to the AB800s, I could start with the Einsteins down a stop. I then shot at ISO 200 and 400 rather than my customary 100 and dropped another couple of stops. I thus never got up to the top levels.

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08-01-2017, 09:00 AM	#16
paulster Senior Member Join Date: Apr 2016 Location: Los Angeles Posts: 159	He's not looking for high-speed sync though. He's actually looking for very short flash duration, which is quite different. Perhaps counter-intuitively high-speed sync requires a long flash pulse (either real or simulated via pulsing) to allow for high shutter speeds. For this kind of work the best solution is a flash with a very short duration as it doesn't have the mechanical limitations of a shutter.

08-01-2017, 09:09 AM	#17
Bob L Senior Member Join Date: Mar 2016 Location: La Vienne (86), France Posts: 223	Originally posted by paulster He's not looking for high-speed sync though. He's actually looking for very short flash duration, which is quite different. .......... That depends how much the ambient light is contributing to the exposure. A long flash pulse duration and fast shutter speed will negate the influence of the ambient.

08-01-2017, 09:51 AM	#18
BostonUKshooter Veteran Member Join Date: Nov 2014 Posts: 338	Originally posted by paulster He's not looking for high-speed sync though. He's actually looking for very short flash duration, which is quite different. Perhaps counter-intuitively high-speed sync requires a long flash pulse (either real or simulated via pulsing) to allow for high shutter speeds. For this kind of work the best solution is a flash with a very short duration as it doesn't have the mechanical limitations of a shutter. OK thks....good point....Broncolor make a big thing of their very short flash duration on some models, and Karl Taylor emphasises that in his stop-action commercial work....however they are quite pricey!

08-06-2017, 06:05 PM - 2 Likes	#19
bfmelton New Member Join Date: Jul 2017 Posts: 6 Original Poster	Update: I just completed a shoot with the rented Einsteins, shooting around 3 or four stops down from maximum. Result: Hard to tell from this crop, but this girl was completely in the air flying across the studio. Ghosting problem solved. Now to save up for Einsteins. :-) Thanks again! Last edited by bfmelton; 08-06-2017 at 06:21 PM.

08-07-2017, 08:43 AM	#20
Edgar_in_Indy Veteran Member Join Date: May 2010 Location: Indiana, USA Photos: Gallery Posts: 2,685	I'm glad you got the problem solved. The Einsteins are really special lights. Just out of curiosity, did you still have motion blur at higher power levels, or did you simply not need to turn them up more for your purposes?

08-07-2017, 07:17 PM	#21
bfmelton New Member Join Date: Jul 2017 Posts: 6 Original Poster	Originally posted by Edgar_in_Indy I'm glad you got the problem solved. The Einsteins are really special lights. Just out of curiosity, did you still have motion blur at higher power levels, or did you simply not need to turn them up more for your purposes? Compared to the AB800s, I could start with the Einsteins down a stop. I then shot at ISO 200 and 400 rather than my customary 100 and dropped another couple of stops. I thus never got up to the top levels.

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