Paul C. Buff, Inc. Technical Forum

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Please restate the question. There is not enough information to form an answer.

I win, I win, I win!

I decoded the question...

Conventional flashes, like Paul Buff's Alien Bees, White Lightnings, Zoots, and ring flash have

t.1 = 3 x t.5

So, my X3200 has a full power t.5 of 1/900 sec and a t.1 of 1/300 sec. 3 x (1/900) = 1/300.

IGBT flashes like Einstein have about that same relationship at full power. t.1 = 1/588 sec, t.5 = 1/2000 sec, so t.1 = 3.4 x t.5.

But as soon as you turn down the power, t.5 equal to t.1 for the entire range of power from 1/2 to 1/256. There's a slight variation at 1/128 and 1/256 power, t.1 is a little longer than t.5, but nowhere near 3x.

At low power settings, t.5 is about twice as fast as t.1.

O.k Sorry about this... I guess what i'm trying to find out is, When does the t1 mode switch to t5?

I been playing around with my units a little bit and when i scrolled up-down in power, t1 mode didn't change. Is this because it was set for standard and not action mode? I'll play around with this more today and see if anything changes...

Thanks Everyone...

t.1 and t.5 will not change to one another. Its kind of like 0-60 vs 0-100 mile an hour acceleration test. They are seperate measurements measuring seperate points of time and will apply to color or action mode. They measure from initial firing of the flashtube to the point where the flash is 50% below max intensity (t.5, as there is 50% intensityy left) and from the inital firing to the point where the flash 90% below maximum intensity (t.1, as 10% is left).

You will not see t.5 displayed on the Cyber Commander or Einstein, however, t.5 is about 1/3 as long on analogue lights and virtually the same as t.1 on most settings of Einstein. t.1 times relay a more realistic description of action stopping ability than t.5 and are thusly used on the Cyber Commander for all units.

Here is an explaination of flash duration from our site:
http://www.paulcbuff.com/forums/viewtopic.php?f=5&t=59

Keep in mind this was written before Einstein, so when you read the description of "thyristor controlled flash", the first paragraph of the description also applies to Einstein, whereas Einstien overcomes the short comings of thyristor controlled studio lights described later in the same section. All of the t.1 and t.5 measuring is still applicable

t.5 and t.1 are not "Modes", they are two forms of measurement.

T.1 time does indeed vary with power on Einstein in either mode . . . see chart at
http://www.paulcbuff.com/pcb2009/e640detail.html

T.1 is the only proper method of specifying equivalent camera shutter speed under continuous light.

Thanks for the help... I'll read up on this to understand further.