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shutter angle and hmi's


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#1 Christian Tanner

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Posted 05 February 2008 - 07:00 PM

hey guys - me again with another shutter angle question...

i was wondering if i have to be concerned about hmi's if they are flicker free - when shooting with a shutter angle of 90° that is.

last shutter angle question - i promise - for now...

many thanx!
tanner
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#2 Bryant Jansen

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Posted 06 February 2008 - 03:56 AM

hey guys - me again with another shutter angle question...

i was wondering if i have to be concerned about hmi's if they are flicker free - when shooting with a shutter angle of 90° that is.

last shutter angle question - i promise - for now...

many thanx!
tanner


With flicker free, you shouldn't have to worry about it.


Bryant Jansen
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#3 Christian Tanner

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Posted 06 February 2008 - 04:26 AM

thanx bryant!

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#4 Fredrik Backar FSF

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Posted 07 February 2008 - 07:41 AM

if you venture over 100fps things might start happening. I speak from experience. It seems not all ballasts hold up as they should. On my shoot it was an alpha 18k from K5600 that gave flicker at 100 fps 90degree angle... so be a bit causious.
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#5 Christian Tanner

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Posted 09 February 2008 - 05:17 AM

thanx fred - good one!

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#6 Fredrik Backar FSF

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Posted 12 February 2008 - 04:54 AM

Just to put more clarity into the fact; these situations with varied shutter angles are tricky ones where one should procede with caution and strange things may happen with any brand at any day.
I have used the alpha 18k to success in these situations also and on the aformentioned shoot there was human error involved and not equipment error.
I just wanted to clarify that it is a trick venture where you must be very meticulous :-)
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#7 Marc Galerne

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Posted 12 February 2008 - 05:05 AM

On my shoot it was an alpha 18k from K5600 that gave flicker at 100 fps 90degree angle... so be a bit causious.

Dear Frederik,
Reasons for a head to flicker are mostly due to either bulb or ballast and not really to the head itself. As manufacturer of the Alpha 18, I called our dealer Anders Johansson in Sweden who remembers about the problem which happened some month ago. The Alpha was not used with a ballast that we provided (neither was the bulb) and apparently when he got there there was no problem. He along with the rental company technicians did tests that showed no signs of flicker when in Flicker Free mode. The unit has been used since without any problem.
Maybe it has been operated in the silent mode on your shoot by mistake... The thing is the Flicker Free mode brings a buzzing noise (especially on big units) and sometimes someone would just switch to silent mode for comfort.... I am just guessing at this point.
Everyone has to be carefull about this because it happens more than we think.
Anyway Frederik, I hope this did not cause you a rejection of the light.

Marc Galerne
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#8 Fredrik Backar FSF

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Posted 12 February 2008 - 11:14 AM

No probs on the light :-)
The alpha is a wonderful light!!
As I said, human error was our problem it turned out later.
All best/Fredrik
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