All language subtitles for 06. Measuring light and achieving the correct exposure.mp4

In this chapter we're going to look at
measuring light and assessing light,

and deciding on what is the correct
exposure for your flashlights to suit

your subject material.

Now if you're a sensitive soul and you
already own one of these, a light

meter, then you're probably not going
to like this chapter too much.

Now let me explain why

I used to use a light meter.

As a matter of fact, I used a light
meter from probably about early 90s

until 2005.

Because a light meter was an essential

piece

of

equipment

for photography

sorry went shooting with film.

Because when you were shooting with
film, you had really no visual clue of

the exposure until the film was
processed.

As matter of fact, in those days, what
we used to do was use a light meter to

take a measurement to get us in the
ball park, adjust the lights to suit,

and then we'd load a Polaroid

sheet into a large five by four camera,
or whatever we were shooting on to then

check the Polaroid exposure before we
made fine tune adjustments.

So in those days, a light meter was
crucial.

But today we have the ability to look
at the picture on the back of our

screens.

We have a light meter built in.

In terms of a histogram, which gives
you a visual graphic display of the

exposure information.

And then even better than that, if we
shoot tethered, we're able to look at

the images coming directly into the
computer,

and we're able to

look at the histogram on the computer
as well.

So

that, by and large, makes a light meter
redundant.

In my opinion.

There is another reason that I'm not a
big fan of using light meters in a

studio environment, and that is that
they contend to influence you in the

wrong direction.

Now, in my opinion, those people that
are hooked or addicted to their light

meters are generally people who don't
have the knowledge about lighting, or

don't understand lighting enough to
realize how easy it is to adjust it visually.

Or they're someone who's spent an awful
lot of money on a light meter and then

feel they need to justify

their position in having spent that
money.

Whereas if you actually understand
light, as you will learn through this

course, and you understand about
assessing it visually, you'll be able

to make much better creative decisions.

And the light meter won't be
influencing you in the wrong direction,

or the correct direction.

I'm going to show you a couple of
examples of where a light meter will

give you a reading.

And that reading may be correct for a
given subject, but then when you change

the subject material, that reading is
no longer useful.

So we're going to run a couple of
tests.

We'll start off with the light meter,
and then I'm going to assess an image visually.

Ok.

So I'm starting off with

my light meter.

You would normally place a light meter
in around this position,

and then you would trigger your flash

to measure

the light.

Now in this instance, I've got a soft
box, an octabox up here, so I'd be

taking my meter reading from about
here.

But I also have a light coming from the
back, which is going to create an edge

light down the side of my model.

This would be difficult to measure
because I can't direct the dome towards

the camera.

And if I direct it towards the light,
that's not really giving me an accurate

reading of this light, because the
light is actually glancing off of the surface

subject.

So for this light, the light meter
isn't really that useful.

It's only useful

for the main light.

Now, if I can just get Emma to trigger
the lights for me, while I just set the

light meter.

So I'm just going to

set that in position and press the
button,

and we'll have a look at that.

So we can see that the light meter is
saying f

5.65.

So that's indicating

an aperture setting of f five, f 5.6

and a half.

So that's the light meter reading.

Let's set the camera to that and see
what happens.

So I'm going into here, I'm going to
change the aperture to f 5.6

and a half.

Take the shot.

So let's take a look at the result.

Here's the image come into the computer.

Now when I look at that image,
immediately to me, it actually looks

slightly overexposed.

And if I look at the histogram,

it's looking ok,

as I would expect, given the range of
tones in there.

But is it the correct exposure for what
you want to achieve?

And this is the problem with light
meters.

They can often guide you, in a way,
towards the wrong

result.

Now, as well as guiding you towards the
wrong result,

they can actually also force you to use

the incorrect setting on your camera.

For example, I've now adjusted

my aperture setting two f, 5.6

and a half.

But this is not the way that you should
really work

when you're shooting subjects,

people, portraits, or many of the
things that we're photographing in this

particular course, you should be making
the creative decision first on the

aperture setting that you desire.

So for example, if you're shooting a
beauty fashion image where you require

lots of skin detail and the hair sharp
and indeed, in detail, you should be

looking at maybe f sixteen as your
desired aperture.

If you want a shallow depth of field
result for a sort of soft portrait

look, then you might want to choose f
two or f 2.8.

Now, by using the light meter, it's
already dictated to me what

aperture setting I should have for the
power of the light that I've got.

Right now, of course, I could change
the power of light until it reached the

aperture setting that I wanted.

But that's quite a convoluted way of
doing things.

For me, the best way of doing it is to
visually assess the image and visually

assess it based on what you determine
first.

And what I determine first for this
particular shot is that I want to shoot

at f 11.

And that's exactly what I'm going to do

so, I'm going to set my camera

to f 11,

and I'm going to take another shot,

and I'm going to look at the result.

Now here is the result that has come in
for aperture setting f 11.

And as we can see, the result is too
dark.

But that's not a problem.

I can see that the result is too dark.

I can also see from the histogram

that most of the tonal range
information is down in the shadow end.

So yes, the picture is dark, but at
least I'm not steering myself away from

using f eleven.

Because now I can simply adjust the
power of the light to suit f 11.

And that is so easy to do.

You need to think of lighting like a
volume control on your music system.

You can turn the power up and it gets
louder.

You can turn the power down and it gets
quite quieter.

So you can turn the volume up, the
picture gets brighter.

You turn it down, it gets darker.

Now if you were listening to your music
system at home, you wouldn't take a

sound reading of it to decide what was
the best volume for your house or for

your pleasure, for that particular
piece of music.

You would just adjust it until it felt
right.

And that's exactly what you should be
doing with your photography as well.

So I'm looking at this picture on
screen, and I'm going to make a visual

decision about the exposure of this
light, my key light.

To start with.

Now I could go to the light itself and
I could adjust the power.

But as you can see, the light is quite
high up on the giraffe boom there.

So rather than climb up there on a
ladder to adjust the power of the

light, I'm going to use the broncolor

app, which will allow me to control the
light.

So this light here is the key light,
and this light here is the backlight.

And you can see that the key light is
set to 5.8,

and the backlight is set to 6.3.

So I'm going to click on the key light.

We know that I'm slightly underexposed.

I'm under exposed, I think, by about
half a stop.

So I'm going to take it up half a stop,
from 5.8

to 6.2.

There we go, wait for the beep.

And we know that the light has now
adjusted its power.

And I'm going to take another test shot.

Now, in the days of film,

you wouldn't want to waste film doing
this.

So a light meter would have been
useful, but it's not costing us any

money to shoot digitally.

So here is the new exposure.

And you can see it is half a stop
brighter than the last exposure.

And actually the skin tones are very
close to where I would actually like

them.

I think we could go up probably two
more tenths of an fstop.

So I'm going to pick up the app.

I'm going to tap in two more tenths of
an f stop.

Take another test shot.

When we go back to the picture, we'll
see this get a little bit lighter.

There we go.

And now I can see that those skin tones
are exactly where I want them to be, visually.

If we compare that to what the light
meter measured,

the light meter measured that.

And this is visually what I prefer.

Now, if I'd followed the root of the
light meter, I might have gone off on a

red herring and been distracted based
on what this

piece of technology was trying to tell
me.

You'd actually be far better using
something like a color checker card in

on your first shot, if you're unsure of
what the exposure on certain tone

should be, so that you can compare them
visually to the card.

However, I'm perfectly happy looking at
the image and assessing it visually.

My next decision

can be about the light at the back.

Now actually it's not too far off the
correct exposure.

But what I'm going to do is, I'm going
to go and I'm going to change the power

of the light at the back here, and at
the moment it's at six points three.

I'm going to put it up dramatically

to

stop, two story stops up, just to show
you something.

So I've just put the backlight up only,

and we'll take the shot again.

And we'll see now that all of this is
overexposed on this side.

There we go.

So now we have quite a bright exposure
running down this side of our model.

It's too strong,

but it was too dark before.

So now I'm going to take it down.

I'm going to take it down a stop.

So I'm just going to slide the app

down one stop

on that particular light,

and take the shot again.

And remember, the beauty here is that
I'm sticking with f.

Eleven that's the desired aperture that
I wanted for depth of field reasons, etc.

Now let's have a look at the resulting
image.

And c,

so now I can see that the exposure on
the side of the face is about right.

Now here's another great example of why
a light meter isn't always your best option.

If we actually look at the light on the
side of the face here, and we look at

the light on the neck, we can see that
this dummy is made of two different materials.

One of those materials is diffusing the
light more because it's more of a mat

textured surface, and the other one is
reflecting the light more because it's

more of a gloss surface.

And the result

is that one of them is overexposed,
while one of them is about the correct exposure.

Now this is simply due to the
characteristics

of the surface material and its texture.

Now, no light meter can tell you or
analyze the surface characteristics or

the texture of a subject.

And that's exactly why using a light
meter can be deceptive.

Let's explore that a little bit further,

because we've now obtained

what I believe to be the correct
exposure

for this particular subject matter, for
this particular

material.

Now if the light meter had got this
exactly right, and had determined that

to be the correct exposure, exactly as
it is, then great.

But let's see what happens if the
subject material changes, but the light

Powers stay exactly the same, because
the light meter

doesn't know what you're photographing.

So it would still give me the same
reading,

whether I'm photographing this model or
whether I'm photographing this black

shoe.

So I'm going to change this in now for
the black shoe on a black background,

but leave the light settings exactly as
they are, and make the assumption that

the light meter, which can only measure
the front facing light, is not aware of

what it has got behind it.

And let's see what happens with the
lighting.

So I'm going to leave the

camera in exactly the same position.

I'm going to put the shoe in the same
position as our dummy was.

I'm just going to check that it's in
exactly the same position.

It needs to go

out a little bit.

Maybe Emma can just give me a hand a
second and just go and take that shoe.

And

I want you to, I'm not touching the
focus on the camera.

So we're going to either pull the shoe
forward or backwards, until it comes

forwards a little bit more.

There we go.

A little bit more.

Right?

So that's in focus.

So that's where the dummy was, because
that's perfectly in focus, and the

focus is locked.

Manually.

I'm just going to pull in a dark
background.

That's not obscuring.

This light, this light is still going
directly to the shoe, so we could get

the edge lighting on the shoe.

This light is falling directly on the
shoe.

So we'll see, the background needs to
move in a little bit further and take

it aback a little bit, just so it
doesn't block that backlight.

So backwards and to your right a little
bit.

Please stop there.

Great.

Ok.

So we have not changed the power of the
lights.

The lights are exactly the same power.

This slide has got clear direction to
here.

This one is in exactly the same place.

We haven't changed the exposure
settings on the camera.

F, eleven.

Still, we haven't changed the power of
the lights.

So if the light meter had given that
reading for the last shot, it would

give the same reading for this shot.

But let's look at the result.

Now, if we go to this picture, the last
picture was correctly exposed for those

power settings.

But now with a different subject
matter, different material and

different textures, it is completely
underexposed.

And this is the problem

with light meters.

They only assess light

based on

a mid range value

it doesn't know whether you're shooting
black on black, or white on white, or

gray on white, or cream or beige on
white.

It has no idea what you're shooting.

It has no idea whether the surface is
glossy or whether it is mat.

It has no idea whether it is leather,
whether it is metal, whether it is

steel, whether it is plastic.

All of these things, and all of those
factors contribute

to the way light interacts with the
subject and the way it looks visually

in the final picture.

If we're trying to make creative
decisions, let's leave the creativity

to the photographer,

not to the technology.

Let's leave the creative decisions
about what aperture setting to start

with.

Let's leave the creative decisions
about whether to turn that light up

separately, whether to turn that light
down, and let you make those decisions.

You have all the tools you need,
visually, with histograms and an image,

be on the back of the camera or
tethered into a computer, you have all

the tools you need to make that
assessment yourself and make those

decisions yourself.

Now

before we just wrap up this chapter, I
want to talk through some example

images.

Some of these images are images that
from this particular course that you're

going to see coming up.

Some of these images are other images
of mind that I've shot over the years.

I want to show you these examples as
clear examples of where a light meter

would fail, because the measurement of
the light required would have been

inaccurate.

The creative decisions made were made
for a valid reason to give the shot the

look and the ambience and the feel that
it has ended up with.

Let's take a look at those pictures.

This first image is a perfect example
of where a light meter would not be effective.

And this is because I've chosen

to use the underexposed

shadow side of the image as my main
base exposure.

The image

is effective because of the rim
lighting around the model's neck body

and hair, and then the small pool of
light

that I've placed on to the eyes and
face.

But the main body of the image is
actually underexposed.

And that's my creative choice and
creative decision.

Had I measured that with a light meter,
the reading I would have been given

would have been the wrong reading for
the desired effect that I've achieved.

Here.

A similar result with this image.

In this shot, we through paint at the
model to create this cloak of paint.

And you can see that again, most of the
lighting is from the back, so that

we're backlighting through the paint to
create the brightness through the paint

on side of the face,

and also create a rim lighting around
the edge of the face as well.

So again, most of the face is in the
shadow side.

And in that shadow side is what we
would call under exposure.

It suits the shot, it's how I wanted
the shot to be, and it was my creative

decision.

And it's another example of where a
light meter would not have given me the

correct reading.

This next image is actually from this
course.

You'll see me shooting this shot later.

And again, you can see that this image
is strong with rim lighting.

The model is lit all the way around the
edge of the body and around the edge of

the hair, as well as the gradient glow
on the background.

The face side, body side of the model
is underexposed,

but it is the correct exposure for the
creative effect that I wanted to achieve.

And finally, this is another example
from this course.

And you can see that the model looks
even more underexposed on the face

because I've gone for a very
underexposed shadow

side detail.

And the emphasis is on the rim,
lighting on the jacket, on the coat and

the hair, and then the very fine stripe
of light across the model's eyes.

So whilst

the majority of the shot is
underexposed,

it's exactly what I wanted.

And a light meter would have been of no
use here.

So hopefully you can see from those
images why I choose not to use a light

meter.

I'll certainly not used the light meter
since the days of film, because I

believe it can actually direct you in
the wrong way.

I like to make my decisions about my
photography from a creative point of

view.

And I think if you try to do the same
and assess your images visually, you

will grow stronger as a photographer,