Hi everybody welcome to another episode
of Exploring Photography
right here on AdoramaTV,
brought to you by Adorama.
It's the camera store that has everything
for photographers like you and me.
In this episode I want to talk to you about
the histogram and how you can use it,
to make sure you're getting the correct
exposure and to avoid
dynamic range issues.
In other words,
how does the histogram help us
in real life shooting
from day to day?
Well first, let's talk
about what the histogram is.
When we take a picture
our camera is capturing
not only color
but tonal values.
In other words,
absolute black, to middle gray,
to absolute white
and everything in between.
What the histogram does
is, it plots all those values
on a scale so we can see
how many black pixels or dots
do we have
in our picture,
how many gray pixels,
how many white pixels?
We can use that, to see if our
exposure is correct,
or if we have
issues with things either
too bright or too dark.
In other words, "dynamic range".
Now, to help understand this
let's think about
a classroom.
So we've got a bunch of students
sitting in desks.
Some of the
students are pretty smart.
They're going to get A grades.
Some of them are going
to get B's, some C's
and then we're going
to have some kids that aren't
so disciplined.
They're going to get D's
and some will fail the class,
they're going to get F's.
We can take those grades,
those values,
and we can plot them
on a scale
and show the distribution
of those values.
So the A's will go here,
the B's will go here,
C's, D's and our F's.
The important thing to understand is,
it doesn't really matter where those
students are sitting in the classroom.
Doesn't matter if the A students are on
the left and the F students are on the
right, it doesn't work that way.
It's just showing the distribution of our values.
The A's go on the left column the B's
next to it, all the way over to the F.
In the same way when we take a picture,
it's not showing us what the different values
from left to right in our scene,
it's just showing us on the left-hand side
of that histogram
that's how many black pixels
we have in our camera
and how many middle grays
and how many whites.
To illustrate this point,
I found this wall here.
There's a black portion
and a white portion
but watch what happens
if I take a picture
of just this white door.
Watch what happens.
So I'll take a picture here
and now I'm going to take a picture of
this black section
right here.
I'll do that.
Okay
Now if we look at these two images
side by side,
you'll see that they
are both gray.
Now the reason for that is the camera's
through the lens metering,
is trying to average
all these tones out
to get middle gray
but if it's white?
It's going to do something that's wrong,
it's going to make it gray
and if it's totally black
it's also going to be wrong,
it's going to overexpose and make
it gray instead of black.
Watch what happens
if I take these pictures together.
So I'll put the black door
and the white wall together
and now you can
see that we have both black and white.
So how do we know in a real-life
situation if our camera was getting
something wrong?
Well, that's where the histogram comes in.
So if I take a look
at my histogram
for the black wall,
you can see clearly that it's right
in the center.
So my histogram is telling me
this is overexposed.
If I look at the
white wall you can see again that my
histogram is showing me all the values are
right in the center saying,
hey this is underexposed.
So using that histogram I can see
if my camera is getting my
exposure correct.
Now, we're not going to
ever be shooting,
I hope, just a black
wall or a white door.
We need to look
and see how this is going to work
in a real life situation.
So let's do that next.
Here are some tiles that have caught my
attention here on this busy street
and what I want to do
is take a picture of this.
I also want to get some of this
pipe here because it's got some texture
and I really like that.
Now because these are almost white,
I think my exposure
might be off,
just like that white door.
So I'm going to frame this up just
a little bit here,
make sure I'm all in focus.
I'm using Aperture Priority mode,
and I'm shooting and when I look
at my histogram here
I can see that it is underexposed.
This on the histogram
should show up in the highlight area
but it's showing up
right in the middle as middle gray,
so just like that white door,
this is underexposed.
So what I'm going to do is,
I'm going to use Exposure Compensation.
I'm going to adjust my
exposure by about a stop and then I'm
going to shoot again.
This is going to
slow down my shutter speed.
Now take a look.
Now that is showing up in the
correct area of my histogram,
right in the highlight area
toward the right side
of the histogram
and that is the correct exposure.
So the histogram is going
to let me know if this is correct or not
without having to go into
post-production to make adjustments.
Our histogram can help us understand
if we have any exposure issues,
specifically dynamic range issues.
Now, dynamic range
is our camera's ability
to capture the darkest of darks,
to the brightest of brights
and how much of that
we can capture
is our cameras dynamic range.
If you have something that's a little bit
too bright or a little bit too dark
it will fall out of the exposure.
In other words,
it's going to have no detail in
the brights or no detail in the darks.
We don't want that
and so our histogram can
tell us if we have an issue.
So behind me
I have sort of a bland scene but it's
perfect for illustrating this.
I'm going to turn around here,
I've got this little patch of sky up there.
So I'm going to take a picture of this little
grove of trees here.
When I do that
I can look
at my histogram and my histogram
is telling me that I have an issue over on
the right-hand side of my histogram,
there's a spike.
We have our whites that
are climbing the wall.
In other words, there's a
spike to the right and that's an
indication that something is overexposed.
So if I zoom in,
I can see that clearly
the sky is way overexposed.
My histogram is telling me I've got an issue
with that part of the sky so I can
either shoot a HDR image
or shoot at a different time of day,
which is probably
the best solution,
or just shoot from
a different angle,
or shoot something else.
Right now my histogram is saying
if you shoot that, right now,
I've got an issue.
Our histogram can also make sure
that we have a proper exposure
and tell us if we have any issues.
Now check this out,
so Salim here
who's been doing some
B-roll and camera operating,
so he's been
running the video camera for me,
he has volunteered
to be the model today.
So I'm going to take a picture of him.
Behind us we have sort of,
a dark background
we have some overcast
light right here,
really nice soft light so I
want to see if this is going to give us
a proper exposure.
So I'm shooting at f/1.4, ISO 200
at 1/750th sec.
Salim, look right into the lens here.
Take one more shot,
and then what I'm looking at,
on the histogram, is to see
if I have any issues.
But my histogram shows me
that I have room to the left
and room to the right
and all the values in between
are falling in the middle
of that histogram and that means,
that I have nothing in this scene
that's absolute black,
nothing that's absolute white.
That means in post-production
if I want to tweak this to make it a little
bit more contrasted,
I've got room to grow.
This is a good exposure.
Nothing's climbing the wall
to the right or the left.
I can just look and see that
everything is good.
There you have it,
the histogram can help you
when you're out shooting
to make sure you get a proper exposure
and to make sure you avoid
dynamic range issues.
If you want to know more about the histogram
specifically for post-production
check out the Adorama Learning Center,
there's all kinds of things,
in fact, one of my
favorites is my video about
using the zone system
for black and white photography,
make sure you check that out.
There's something else
I need to tell you, I'm starting to write
articles every other week
for the Adorama Learning Center
so check them out.
It's absolutely free and also don't
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Thank you so much for joining me and
I will see you again next time.