In this episode I'll explain stops and how they apply to the exposure triangle.
AdoramaTV presents, Exploring Photography with Mark Wallace.
Hi everybody and welcome to another episode of Exploring Photography right here on
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I've been explaining the exposure triangle in the last episode
I gave a high-level
overview of the aperture and shutter and the ISO
those three things that make up the exposure triangle and sort of how they work
together
but before we go any further we need to understand
stops, what the heck is a stop? Well
let me explain it to you in this way; if we had a scale
and we had a pound on this side and a pound on this side, that would be
balanced or if I added a pound over here
I need to add a pound on the side to balance that out, if I added a pound over here et cetera,
so we have the standard unit of measure and that's for
weight. Well if we're talking about light we measure light
a little bit differently we're talking about shutter speeds, we talk about
fractions of a second
8,000th of a second or a half a second, we're talking about aperture values
that thing in your lens opens and closes, were talking about things like
f2.8 and f/11 and so what we're trying to do is figure out
is if my shutter is open and letting in this much light and I need to balance that
out for a correct
exposure, what should my aperture value be, or my ISO
value and they're all using different kinds of numbers and so it's hard to say
well if I go from f/8 to f/11 then I need to go from a shutter speed of 8,000th...what?!
...it doesn't make sense. So to make everything make sense
photographers invented this thing called 'stops' and it just means
half as much and twice as much. So if I have this
gale of light and its balanced, and I take half as much light
off of this side I need to put twice as much on the side to balance that out so
I take a stop
from the side, and I put a stop on this side. Stop just means half as much
or twice as much. Now I know everything is going 'Agghhh' in your brain
if its not working out, so really make this make sense, I've got an animation
and I'm going to explain all of this to you. Alright, we need to make sense out of all this
mumbo jumbo, remember
a stop just means twice as much light or half as much
light and to make this crystal clear let's bring back our animation, our exposure
triangle we have our shutter,
our aperture, and our ISO, remember our shutter has different shutter speeds to let in more or less
light depending on the speed, we have our aperture value that lets in more or less light
depending on the opening, or the aperture value, and we have our ISO
that gives us a sensitivity, so essentially
more or less light depending on our ISO value.
Now for the sake of argument let's say that we have a nice sunny day
and we have our camera set to f/16 and our shutter speed is 125
and our ISO is at 100 we have a proper exposure at those settings,
well for some reason we don't want to shoot at f/16 because of depth of field lets say
so we want to shoot at f/2.8, so let's see how stops affect this.
So if I take my aperture and I change it to f/11
now I'm one stop, letting in one stop
more light and things are out of balance, I'll be overexposed,
and so I need to change my shutter speed to 250
that's a one-stop and now things are in balance again,
I'll go to f/8 now things are out of balance, to balance that out
I'll go to a shutter speed of 500, so every time I move the aperture by one
stop, lets go to f/5.6,
I need to move my shutter by one stop so we'll go back to 1000th,
f/4 to 2000th on my shutter, finally f2.8
I'm now at 4000th. So every time one thing moves by one stop
something else has to move by a stop up or down to keep our exposure set
perfectly. Now let's just say for some reason, maybe the clouds come out
and my shutter speed now has to fall. So the clouds to come out
and it blocks the light, we have two stops less light.
So now our shutter wouldn't be 4000th, it would be 2000th, that's one
stop
1000th, that's two stops because the light changed
our shutter speed has to change. Well what what happens if we want our shutter speed
to be at 4000th, we can't open our
aperture any wider, f/2.8 let's say on this lens is as wide as it goes
what do we do? Well we have our ISO so we'll go from
ISO of 100 to 200, that's one stop
that lets us change our shutter by one stop, so now we're at 2000,
we'll let in, we'll be more sensitive to light we'll go to from and ISO of 200 to 400,
that's one stop that means our shutter can then go one stop to
4000th, so you get the idea. With stops we can figure out exactly what's
happening
if we move our aperture by a stop and things are balanced, we have to either move our
shutter by a stop to keep things balanced
or move our ISO by a stop. So once you change one thing in the exposure triangle
you have to choose one of the other corners and change that
to keep things balanced, and its really nice because it helps us do calculations
really fast
and most cameras on the dials, each click
is usually one-third of a stop
or 1.1/2 of stops, so if you have a click this says:
two clicks on the aperture ring, well thats just two clicks on the shutter ring to
balance things out,
you'll see that when you're using specifically on a Canon or a Nikon or
Panasonic
on the dials in the front if you click the shutter button twice
you'll need to click the aperture dial twice to keep things in balance
and the more you use that you'll get to know those clicks and you'll go 'Ah, that's it,
the clicks equal a third of a stop' and if you
have a camera you can actually go in on most cameras and
change that to make those clicks make either a third stop,
a half stop, or full stop its up to you I recommend keeping at a
third stop increments, when we get to shooting in manual mode at the very end
of the exposure triangle series
we'll see how those little clicks are
really going to come in handy. But that's all there is two stops, just remember
a stop means half as much or twice as much, so if we move
one thing by a stop we have to move another by a stop to keep
everything balanced. Well thank you so much for joining me in this episode
of Exploring Photography,
don't forget you can learn all about stops and understanding exposure
triangle and advanced stuff and flash photography, all of that all at the
Adorama Learning Center, the Adorama Learning Center has tons of resources
all about the exposure triangle and stops, and advanced metering and all
kinds of things so check that out
and don't forget to subscribe to AdoramaTV that way you get
all of the content absolutely free every single time. Well thanks again for
joining me
and I will see you next time!
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