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NewB Question
http://www.paulcbuff-techforum.com/viewtopic.php?f=8&t=2476		 Page 1 of 1
Author:  cmpdesignz [ Sat Oct 29, 2011 1:50 am ]
Post subject:  NewB Question
I apologize for such a stupid question, but what is a "t.1" method and a "t.5" method?
Author:  ltwimberly [ Sat Oct 29, 2011 9:25 am ]
Post subject:  Re: NewB Question
t.1 and t.5 are flash durations. It's a way of expressing how long a particular flash emits light. t.5 is the time it takes for the flash to emit half its power. t.1 is the time it takes to emit 90% of the power.

These are relevant when considering a flash's ability to freeze motion. If these durations are relatively long, then moving objects may be blurred in the picture. (Very similar to a slow shutter speed when using a continuous light source.)

The lower the t.1 or t.5 is, the more able the flash is to freeze motion. t.1 is a more sensitive indicator and discriminates more finely among flashes. That is, two flashes could have the same t.5 and this might imply that their motion-stopping capabilities are the same. But if, in fact, one of them had a lower t.1 than the other, then that flash would actually perform better. This is because the light emitted between the 50% and the 90% mark is capable of impacting the exposure, but is not accounted for in the t.5 measurement.

There is a long article about all of this on this website. Go to the home page, choose the help section>studio flash explained>flash duration.
Author:  cmpdesignz [ Sat Oct 29, 2011 9:39 am ]
Post subject:  Re: NewB Question
Thanks. You answered my question with your answer. Now all I need is to find out the flash duration of an Ultra 1200 at full power. Most appreciated.
Author:  Luap [ Sat Oct 29, 2011 9:59 pm ]
Post subject:  Re: NewB Question
Here's the t.1 and t.5 times for all permutations of WLX. Ultra1200 durations are approximately the same as WLX1600 in "full mode" . . . 1/1600 t.5 and 1/530 t.1 @ full 640WS . . . about twice as long when dialed down to 1/32 power.

http://www.paulcbuff.com/x1600.php
Author:  cmpdesignz [ Sat Oct 29, 2011 11:51 pm ]
Post subject:  Re: NewB Question
Luap wrote:
Here's the t.1 and t.5 times for all permutations of WLX. Ultra1200 durations are approximately the same as WLX1600 in "full mode" . . . 1/1600 t.5 and 1/530 t.1 @ full 640WS . . . about twice as long when dialed down to 1/32 power.

http://www.paulcbuff.com/x1600.php


So "t.5" is at 1/32 power?
Author:  Luap [ Sun Oct 30, 2011 1:00 am ]
Post subject:  Re: NewB Question
Twice as long as 1/1600 (full power t.5) = 1/800 (1/32power t.5)
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