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Bevanj

Z330 flash duration

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I got bored and have just been doing some testing on my Z330s with an oscilloscope and some photodiodes. If anyone is interested, and as curious as me... here's a rough table of the flash durations of the Z330! They're not T.1 measurements, but are pretty close.

 

FULL = 3300us = 0.0033sec

-0.5 = 680us = 0.000680sec

-1.0 = 534us = 0.000534sec

-1.5 = 430us = 0.000430sec

-2.0 = 348us = 0.000348sec

-2.5 = 300us = 0.000300sec

-3.0 = 257us = 0.000257sec

-3.5 = 221us = 0.000221sec

-4.0 = 186us = 0.000186sec

-4.5 = 165us = 0.000165sec

-5.0 = 130us = 0.000130sec

-5.5 = 110us = 0.000110sec

-6.0 = 97us = 0.000097sec

For an interesting comparison of output power.... with the standard -0.3 soft diffuser in place, the Z330 somewhere between -2 and -1.5 (348us-430us) settings puts out the same amount of light as a 580EXII on full power (5600us!) with the wide angle 14mm diffuser flipped down. Impressive! The colour temperature is very different too - but that is to be expected. :)

Bevan

Edited by Bevanj

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interesting.

But better express the numbers in terms of 1/xxx sec, which is easier to read for photographers.

That is

 

full power = 1/300 sec

...

-6 = 1/10'000 sec.

 

But thanks anyways.

juerg

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Hi Bevan,

 

Very interesting measurement, but are you sure it is correct?

 

Should there not be half of the time per one f-stop less (or does the Z330 have variable output power (Watt), depending on setting)?

 

Wolfgang

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Yep. Pretty sure they're correct. For example, here's a scope plot for @ -6.0. The photodiode saturates, so I can't take 0.1T measurements where the duration is specified as on the rise at 10% of maximum brightness right through to falling at 10% of maximum brightness.

I guess I could put the photodiode a larger distance away from the flash...

Bevan

post-67761-0-96403200-1543619467_thumb.jpg

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Oook. That definitely works. At a distance with a sheet of paper to dissipate some more power, I can measure the peak, and thereby generate some 0.1T numbers. Here's my 580EX2 on full power. Full power off the datasheet for this flash is 1/250sec i.e. 4ms. Looks like I'm right on the money.

post-67761-0-90709200-1543620618_thumb.jpg

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Ok, Z330 0.1T numbers - these I am sure are correct. Wolfgang, light output is not linear relative to time. Have a look at the PDF, you'll see what I mean.

Some interesting reading...
https://strobist.blogspot.com/2010/06/rise-and-fall-of-machines-understanding.html

-6.0 = 37us = ~1/27000
-5.5 = 47us = ~1/21000
-5.0 = 57us = ~1/17500
-4.5 = 67us = ~1/15000
-4.0 = 84us = ~1/11800
-3.5 = 105us = ~1/9500
-3.0 = 137us = ~1/7250
-2.5 = 179us = ~1/5600
-2.0 = 230us = ~1/4300
-1.5 = 312us = ~1/3200

-1.0 = 421us = ~1/2400

-0.5 = 577us = ~1/1750
Full = 2.06ms = ~1/480



Some interesting stuff to be read from this - especially for those shooting mirrorless or point&shoot... If you are cranking up your shutter speed to 1/500 and above, at full power, you are starting to cut into the flash output and loose light in that way. For the rest of us shooting through an actual shutter maxing out at 1/200 sync speed, it's not so much of a concern.

Z330 T.1 output.pdf

Edited by Bevanj
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thanks, these look very close to my measurements on the z240 using a slightly different set of hardware.

Cheers

Bill

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Cheers Bill, It's interesting to hear the Z240 numbers are similar. I'd be curious to know just how similar.

Bevan

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Reply:

Now you have made me go back to the lab and get a notebook. Will post some numbers soon

Bill'

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I would be very interested in the duration of the first and second pulse in TTL for:

f/11 and iso 80 or similar

and

f/2 and iso 1200 or similar

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Dave, first pulse is camera dependent. I did some testing with a 20d, 7d and 5d3 and my 580ex2. All of the combinations, along with the 20d and 7d ibternal flash produce different pre-flash times.

As for the main pulse, that will be distance dependent also.

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Trigger by shorting the strobe trigger pin. My data is

 

 

This is not for 1/10 power but close. Our lab software was designed to measure lifetimes, so this is for 4 half lives. 0.25/e which is about 9%.

If i can get in the lab, I will try to measure the first pulse in TTL from the camera.

 

Cheers

bill

post-141-0-60403000-1544737864_thumb.jpg

Edited by bvanant

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Bill,

 

Thanks for the data.

My main interest is in TTL. I understand that for various cameras, the first TTL pulselength can be different as well as the separation between first and second pulse. For my RX100iv setup, for example, first pulse is always 300 microseconds long and pulse separation is always 78 milliseconds.

 

The kind of data I'm most keen to get is second pulse duration for TTL with different scenes that would require short pulse (high scene illumination) versus long pulse (low scene illumination). The way I get those extremes artificially is by setting the camera for low f/number, high iso (high sensitivity) and for high f/number, low iso (low sensitivity).

 

Below is the type of data I've taken so far for the a7Rii, manual, and different ev settings. I'm hoping to get the same kind of pulselength extremes in TTL.

post-77081-0-27650800-1544745597_thumb.jpg

Edited by davec13o2

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can't you generate the data yourself? BVA

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Bill,

 

I don't have a Z330 and want to verify that it works well in TTL mode before buying a pair. What I have is an ST-100 that works in manual mode only and a YS-03 which works off my RX100iv, but I believe that camera has insufficient pulselength for effective fiberoptic driven TTL.

 

What I'll do is wait for the UW-Technics converter to come out, at that time buy one Z330, and test them together. If satisfactory, I'll buy the second Z330; if not, I'll return both and go back to manual only. Instead of the Z330, I may opt for the new Retra. In any case, I'm planning to test whatever I buy no matter what prior testing with other equipment comes up with.

 

So let's cancel the testing I asked you for, because I'll just be repeating it with the equipment I buy. Thanks anyway,

 

Dave

Edited by davec13o2

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You can't ever tell a lab guy to cancel an experiment. As soon as our optical setup is free, I will give it a go (just for fun).

BVA

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