hi everybody welcome to another episode
of exploring photography right here on
adoramatv i'm mark wallace
today i'm going to show you the flash
exposure triangle
a little bit different than the normal
exposure triangle in fact
you can sort of think of this as the
exposure diamond because when you add a
flash to your camera you no longer have
one exposure you have two you have the
ambient light which is what we're going
to be doing with this big window over
here lots of light coming in that's
ambient light light from the sun or
light from your environment the light
that we have to react to
that's what we use the normal exposure
triangle to control
and then we have light from our flash so
we've got a flash right here
that's a different exposure triangle and
so when you're using a flash
in the studio you only have to worry
about the flash exposure triangle
and when you're using your camera with
no flash outside you only have to worry
about the exposure triangle
but what happens when you're trying to
mix those two things
ambient light and light from the flash
well you can change
different things to either increase or
decrease the exposure from our ambient
light
or increase or decrease the light from
the flash and those two things can work
independent of each other and so that's
where our flash
triangle becomes a flash diamond because
those two things
join and we have well you'll see in just
a minute our model is here
it's juana okay before i show you how
everything is set up let me remind you
the photos i'm going to show you in this
video are for us to understand the
principles of the photography and how
everything works it's not something
you'd want to hang
on the wall over here on this side of
the room we have
tons of ambient light coming in so we
have this giant window letting in
tons of light from the sun that is
controlled by our normal
exposure triangle that is our iso
our aperture and our shutter speed on
this side
over here we have a flash that flash
is controlled by a different exposure
triangle the flash exposure triangle
that is our iso our aperture and the
power of our flash the flash
power now the cool thing is we can
control these two exposures
independent of each other so i can
change the exposure over here to make
the background brighter or darker that
ambient light
i can change the flash power to make the
flash exposure brighter or darker
and so we're going to walk through all
of that stuff the thing to remember
is that both exposure triangles share
two things
the iso and the aperture they both
affect the ambient and our flash so we
need to lock those in and not change
them
we only want to change our shutter and
the flash power
to change those two exposures all right
so we're going to begin
with our ambient light so i have my iso
at 100
my aperture at 16 and then my uh shutter
speed is going to be at
60th of a second to begin with so uh
my spanish is so bad all right i've got
this all focused
up okay so i'm going to shoot at 60th of
a second
then i'm going to shoot another one here
at let's do uh
125th of a second so half that we'll do
another one here maybe 180th of a second
and we look at those you can clearly see
that the background
is getting a little bit darker a little
bit darker a little bit darker all right
i like the 60th of a second so i'm going
to go back there
set my exposure to 60th of a second now
what i want to do
is i want to turn on my flash and meter
this
so that the flash matches my
exposure triangle so really what we need
to do is make sure that it meters f 16
so that the flash and the ambient light
are balanced i
do that by changing the one variable in
our flash exposure triangle
that is not in our normal exposure
triangle that's the flash power
so let's start so what i'm going to do
here is i've got this little remote
control that allows me to change the
power and trigger the flash
all that kind of stuff so what i'm going
to do is i'm going to turn on my
meter and i'm going to meter this so i'm
metering it
right here and that meter is at f16
that is perfect so if i had not enough
light
so let's say i metered this that's f13
so let's say it's f13 to begin with what
i need to do is use my remote or the
power on the back of that
and just increase that until
that meter's at f 16. once that's
set then my two exposures are equal
they match so it'll balance all that
stuff so now what i can do here
is i can put this uh remote on my flash
this is where it gets fun okay juana
perfecto perfect
so here's the first shot and you can see
that those
are balanced now what i'll do is i'm
going to roll my
shutter speed down to 30th of a second
and go down to 15th of a second i'm
going to take that up to
125th of a second up to
180th of a second now look at these
images
what you'll see is that the ambient
light exposure
is changing but the flash exposure is
not
that's because we're only changing that
one variable in our
exposure triangle that's not in our
flash exposure triangle
the shutter so that's affecting our
ambient light but it has no effect
on our studio stroke now what i'm going
to do here is the opposite
so i'm going to set my shutter back at
60th of a second
now what i'm going to do is uh portravor
oh no no no so one is going to put her
finger up number one
that's a proper exposure then i'm going
to take my
flash output down uh numero dos
okay i'm going to take my flash output
down considerably
numero trace okay now when we look at
these
notice that the flash exposure is
changing
but the ambient exposure is not we can
change and control these two exposures
independent of each other
knowing our flash exposure triangle and
our normal exposure triangle
joining them to make an exposure diamond
i guess that's what you would call it
shutter speed controls the ambient light
flash power controls the output of their
flash
we can control those independent of each
other that's all there is to it
now i know there's much more to it flash
duration and sync speed and
all that kind of stuff so make sure you
look at the links in the description of
this video to really fully understand
everything that's involved understanding
why we chose a certain aperture and
shutter speed and all that stuff
links in the description of this video
it explains everything
thank you anna for all this fun we've
had today
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thanks again for joining us and i'll see
you again next time