All language subtitles for 04. Understanding flash duration.mp4

Why is flash duration important in our
studio or location photography?

Well, let's explain a little bit about
what flash duration actually is.

Flash duration

is the length of time of the burst of
light that comes out of a studio flash.

And that varies quite dramatically

across different brands and across
different types of light.

Now, if you're just shooting portraits

or still life objects, then flash
duration doesn't really matter, because

the objects or subjects you're
photographing don't actually move.

But if, like me, you're photographing a
lot of fast moving objects, then flash

duration is very important.

Let me show you a little bit about what
I mean.

Now, in these clips, you'll see there
are models moving fast within the

scene, or there are fabrics and dresses
and things swirling in the wind

that move fast relative to the camera.

Now, it is the speed and duration of
the flash

that is responsible for freezing these
items sharp,

not the shutter speed of the camera.

In these clips you'll see liquids,

paints and other types of liquids
crashing and smashing into each other

or exploding.

These also require very fast flash
durations to freeze those images sharp,

because the duration of the flash is
actually faster than the fastest

shutter speed on the camera, and that
allows you to do this precision accuracy,

sharp, frozen image work.

Now there are some important differences

in the way that manufacturers of studio
flashes measure the duration of the flashburst.

You will come across two types of
measurements,

one called a t 5

and one called a t 0.1.

The t 1 measurement is far more
accurate and important than any t 5

measurement that you see.

As a matter of fact, a t 5

measurement is actually quite
misleading.

For example,

this particular cyro slide, which is a
very, very high speed flash duration,

can attain about 1800500th

of a second.

Flash duration with a t 1

measurement.

If that was a t 5 measurement, this
thing would attain about 1415000th

of a second.

So the

higher number that is applied with a t
0.5

reading is actually a little bit
misleading.

Now let me explain a little bit more
about that.

When we consider flash duration and
flash bursts, we have to look at the

way flash works.

When that flash fires, there is an
initial rapid build up of the intensity

of the light, and then the bulk of the
light exposure is here.

Then the flash will tail away

but the part that tails away still

is exposure.

It's still light, and that light is
still recorded.

So in a t 0.5

measurement is not always accounting
for the extra exposure that will happen

afterwards, which causes some
confusion.

And it is a little bit misleading,
because that extra

flow of light that is coming after that
part portion,

what could actually cause ghosting or
image blur?

Now with a t 0.1

measurement, if we know we can attain
10000th of a second at t 0.1,

then we know we've got a very, very
fast flash.

And that measurement is counting for
nearly all of the whole flashburst.

There's also some other things to
consider, and that is the technology in

the flash.

For example, with the Cyrus and the
mighty scoro packs, the flash has a

special cut off technology.

So rather than the flash fire in a
burst and then gradually fall away, the flash

cut off technology

cuts the flash off more abruptly and
more cleanly, so that it stops more quickly.

Now the best way to put this to the
test is to actually

test it in real life.

So I'm going to use a spinning fan

with this yellow square on it.

And I've taken the front cage off the
flan, off the fan.

So please be careful if you're going to
do this yourself, don't go and stick

your fingers in the fan.

I've put that yellow square on one of
the blades of the fan,

and I'm going to fire

the cyros light

and record the exposures

and see

frozen we can get the blades of that
fan and see how sharp we can record

that image.

And then I'm also going to compare it
against the mighty scorrow pack, which

is one of the fastest flash duration

systems on the market.

And we'll see how close we can get with
this flash

against the scorrow.

And we may even put in another type of
flush as a comparison as well.

Ok, we're ready to do our flash
duration test.

So I've got a camera

with a seventy to 200 lens,

which is focused over on that fan.

And I've got our three lights that
we're going to test.

So we're going to test this older model
light that doesn't claim to have a fast

flash duration.

And then we're going to test the very
fast cyros against one of the

ultimate flash systems, the scoro.

So let's have a look.

How we're going to do it.

Step this way.

And let's have a look.

We've got this fan,

and I've put a yellow square on the
fan.

And I'm going to turn the fan on.

And you can see how fast

that thing is spinning.

That thing is spinning so fast that
that yellow square looks just like a blur.

So it'll be really interesting to see
how much detail we can capture with

just the burst of flash.

Now,

the other thing that you might have
noticed is that I've kept it quite dark

in this area.

So we've got this area out here lit,
but back there is dark.

And that's because we don't want any
ambient light affecting the shot.

We just want the flashburst to record
the exposure, no other light.

let's get started.

I've got the camera tethered into the
computer, into light room.

And for this flash, because it's an
older flash, I've got a sink cable, so

this will send a signal to fire the
flash, but that doesn't affect the

speed.

The burst of light will be exactly the
same.

Now, to give this flash a chance, I'm
going to use it on a lower power.

I'm going to use it on power three.

I might actually even use it on power,
too, to give it a better chance,

because the lower power on most flashes
gives the shortest

duration burst.

So we've got it on power too.

Just push the test button.

There's the burst of flash.

Now, we'll take a picture.

Actually.

No, what we need to do first is to take
a base standard shot with the fan off.

So we've got something to compare to.

So i'll turn this fan off again.

We'll let those blades come to a stop.

There we go.

And let's just put that

square wherever.

It doesn't really matter.

And I've already focused on the fan.

I'm just going to double check.

All.

Still looks

pretty good.

Let's take a test shot.

Ok?

So I don't know if the exposure's
correct.

The exposure is Miles over,

so we're well over exposed.

So let me just get the exposure
correct.

So that's f four.

So I'm going to go to f eight,

take another test.

Yes.

Ok.

So there looks about the correct
exposure.

So f eight

let's zoom in on this.

There is no movement at all because the
fan is turned off.

So we'll take a note of how sharp the
edge of the blades are.

Taken note at the sharpness of this
yellow square.

And actually it looks like it might be
slightly sharper focus there than it is

there.

So I might just tweak that focus a
little bit first before we get going.

Ok, so I've got it in focus now.

So this shot will be our base shot.

We're on power too.

And there is the yellow square,
completely static because the fan's not

moving.

I'll turn the fan on,

let it get up to speed,

and we'll leave that fan on now

for the rest of our tests,

and we'll take our exposure.

And let's have a look how much motion
blur.

We've got.

Need to zoom out on this shot.

There we go.

So there is flash duration, or there is
a poor flash duration, because

obviously anything that's not moving is
perfectly sharp.

But you can see how much movement and
motion

is recorded

in those fan blades.

And on that yellow square, just look at
the after trail of that image, as you

can see there as a tremendous amount of
after trail on that shot.

So I'm going to change now to the
cyroslight

as a comparison of flash duration.

Ok, let's turn that flash off,

get rid of the sink cable.

Swap this over

the Cyrus in.

Now,

put the cirrus on power too as well.

Just to match up there.

Notice, I don't have the modeling lamp
on either, because that would

interfere,

we've got it on speed mode.

Just going to push the test.

There we go.

Now I'm just going to use the trigger
now, because we need to be able to

activate the flash.

This one doesn't need sink cable.

I can do it with a wireless trigger.

And I'm going to take that shot.

And let's compare.

Now the power

is too low on the flash,

so I'm going to go up or stop.

So I'm going to go up to power three.

But there we go.

Now, a huge difference there.

Huge noticeable difference.

There is a slight,

tiny, tiny, tiny amount

of

blur

on

that

fan blade and on that yellow square.

But compared to that shot,

you can see huge amount of difference,

huge amount of difference.

So

this one's still a little bit dark.

So I can turn the exposure up a little
bit more.

And got to power for

the other

flush.

Power was higher.

Let's take that shot again.

There we go.

Actually that's a little bit too
bright.

Now

I'm just going to turn that down a
fraction,

and let's compare it.

So we have the correct exposure now.

And look at that.

You see fantastically frozen.

I mean, it's almost as sharp as it was
when it wasn't moving.

If we compare it to the motion blur on
that one, look at the amount of trail

of motion blur because of the flash
duration,

compared to the same speed, spinning
blades.

And

then compare that to a static shot,

where it's not moving, tall.

So there's where it's not moving at all.

And then there's it with the cyros,
with the fan blade actually moving and

it's almost

frozen perfectly.

So you can see how if you're shooting
fast moving objects, this very fast

flash duration will be really
important.

And we're getting about 8000th

of a second a t 1 measurement right now
with that particular cirrus flash.

So let's test it against the ultimate.

Let's test it against the scoro, which
is

renowned all around the world by top
studio pros

and used by people like myself as the
ultimate flashpack

for flush duration and power.

So let's go and check that out.

Ok.

So let's swap out

cirrus.

Bring in

the scoro.

So actually this is a

uni lamp head.

And remember, this doesn't have the
capacitor in it.

Power is in the scoro.

And the scoro is a lot more powerful

the amount of brightness that it can
throw out than the cirros, because

obviously it's a much bigger, heavier
pack.

It's also a lot more expensive.

But I'm going to start this one off on
power three.

let me just make sure it's in fast
flush duration mode.

And it is in fast flush duration mode.

So let's do a test

and see what we've got.

Now you can see it's massively
overexposed

because the scoro's so much more
powerful.

So I can actually

close the aperture of the camera down,

or turn the power on the scorrow
packdown.

So I'm going to close

the aperture down to f sixteen,

do the test again, and let's see what
we get.

So

where is our yellow square?

There's our yellow square, and it looks
comparable

to the result that we had on the

cyros.

So

this tiny little bit of movement there
on the cyros,

tiny little bit of movement on the
scoro.

I'm just going to go and try and turn
the scoro power right down to see if it

reduces it anymore.

But you can see, effectively, they're
giving the same result.

It's got the same flash cut off
technology.

But you can obviously see there's so
much more power available to us

with the scoro pack.

So let's see if in the even lower
power, if there's any improvement.

Tiny, tiny bit, actually it's a tiny
little bit sharper

than it was before.

Really good result.

But I'd expect that from a high end
professional pack like that.

And obviously the scoro packs a lot
more expensive, it can do many more

things, and it is aimed at a
professional photography market.

But what that does show us is that the
cyros

does exceptionally well on the fast
flash duration.

Very, very

good performance on the fast flash
duration from what is a

reasonably economical

lighting head.

Now, if we go back as a general
comparison, so there's the shot zoomed

out from the cyros.

There's the shot zoomed out from the
scoro

back to the cyros.

And then on a standard lamp head,

there's what you get with the amount of
motion blur

when you do not have fast flush
duration.

So you can see from those results that
fast flash duration is important,

especially important if you're
considering fast moving fashion shots,

or liquids or objects flying around.

If you're not, then it's not really
something you need to worry about.

But now you understand what

fast flush duration means

and the results that it can give you