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Author Topic: Using Leaf Shutter/Hi speed synch and Lightmeters  (Read 3061 times)

aztwang

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Using Leaf Shutter/Hi speed synch and Lightmeters
« on: November 21, 2015, 07:56:23 pm »

I was shooting a group of soccer players yesterday in front of a goal. I was using my PhaseOne DF+ and IQ250 with a Schneider 55mmLS lens. The ambient light was a brighter than I wanted so I decided to kill the ambient a bit with the use of leaf shutter lens. Camera settings were ISO 100, F10 @ 1/500th shutter. We checked the lighting with a Sekonic 478DR. The meter called for F14 across the entire 24 feet BUT according to my eye and histogram it was perfect @ F10. My question is: Can light meter readings be off considerably when using a leaf shutter lens in a high speed sync application.? My Sekonic is always spot on when using it in a non high speed sync application.

Ciao

Don
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Doug Peterson

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Re: Using Leaf Shutter/Hi speed synch and Lightmeters
« Reply #1 on: November 21, 2015, 10:26:36 pm »

This would happen if you were using strobes with a slow flash duration, since some of the flash pulse was after the shutter already closed. It would also happen if you were using a slower wireless sync or not using the "fast" mode of a wireless sync system that requires it to operate at 1/500th.

aztwang

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Re: Using Leaf Shutter/Hi speed synch and Lightmeters
« Reply #2 on: November 21, 2015, 11:51:56 pm »

This would happen if you were using strobes with a slow flash duration, since some of the flash pulse was after the shutter already closed. It would also happen if you were using a slower wireless sync or not using the "fast" mode of a wireless sync system that requires it to operate at 1/500th.

OK Makes sense. I was using Broncolor Move 1200 @ 9.5 which is somewhere between 1/935 and 1/375 so very well could be the issue. I'll test tomorrow and get lights closer so I can get close to 150-200 ws which will get me around 2150 to 4300. I am using the standard Profoto air remotes which do not have a fast feature.

Don
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abouho

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Re: Using Leaf Shutter/Hi speed synch and Lightmeters
« Reply #3 on: November 28, 2015, 11:51:14 am »

I am using the standard Profoto air remotes which do not have a fast feature.

Actually, if you hold the mode button for about 7 seconds on an Air Remote or Air Sync, you'll switch it to high speed mode. It should beep and the light next to "transmit" will start blinking faster than usual.
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aztwang

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Re: Using Leaf Shutter/Hi speed synch and Lightmeters
« Reply #4 on: December 01, 2015, 02:54:49 pm »

Actually, if you hold the mode button for about 7 seconds on an Air Remote or Air Sync, you'll switch it to high speed mode. It should beep and the light next to "transmit" will start blinking faster than usual.

Thanks!! I never knew that. I wonder if Profoto's fast mode is the same as Pocket Wizards.
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UlfKrentz

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Re: Using Leaf Shutter/Hi speed synch and Lightmeters
« Reply #5 on: December 02, 2015, 05:21:12 pm »

Thanks!! I never knew that. I wonder if Profoto's fast mode is the same as Pocket Wizards.

Still, be aware if your flash duration is longer than your shutter speed you will cut off flash power.
Dialing down energy at the move packs or using twin heads will shorten you flash duration.
Have fun!
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