How Polarizers Work | Polarizing Filters Tutorial

this is an 82 millimeter circular

polariser it was very expensive it one

hundred and fifty dollars and I needed

it for my wide-angle lens

polarisers allow you to essentially

block out polarized light when we talk

about polarization we are talking about

the angle of light now this that may

sound kind of confusing but it

essentially means is what angle the

light direction is if you're looking

almost behind the light wave it's going

up and down then it would be it would be

polarized in the up and down positions

if it was going side to side the left

and right then the light would be said

to be horizontally polarized and the

truth of the matter is when light

strikes a smooth flat surface that is

not metal the light becomes polarized so

we're talking about things like water

shiny wood certain kinds of plastic

cardboard some cardboard can be

polarized light so the idea is that when

light whatever light strikes a flat

surface when it comes off it becomes

polarized in the horizontal plane

meaning that the angle of the light

isn't out side to side so how in the

world does a polarizer prevent that

light from entering into the camera a

pretty good question

and so here I have a polarizer

kokin polarizer this rotates when you

rotate a polarizer it's going to block

the light out at some point so what we

decided to do was to make a blown-up

model of how a polarizer works it's

essentially a teaching tool a visual

teaching tool that this is how

polarizers work in that polarisers are

made up of many very very small very

very thin very very parallel lines in

the filter so the way this works let's

say we're shooting water okay and we

have this polarized light bouncing off

water coming into our lens

when light hits water and it bounces off

it becomes polarized left-to-right in

the horizontal plane so here comes the

wave it's all doing all kinds of crazy

things it hits the water and it comes

off going side to side what happens is

that light is able to still go through

the filter and not be interfered with in

any way so what's happening when a

photographer rotates the polarizer and

light is coming off the water here it

comes hits the water and it's going side

to side look what happens the wave is

interfered with because it's doing this

motion side to side and the light cannot

get through what this means is the only

light that will be able to pass through

the filter is the unpolarized light

that's bouncing around the angles are in

all directions only light coming like

this is going to be able to get through

so I know that's kind of a rough

explanation but if you think of a

circular polarizer as a set of parallel

lines and that when you rotate them that

is going to block polarized light so

it's moving up and down or left and

right and that's why you rotate the

filters to find the position where it's

blocking light if you have two polarized

filters and you take one of them and

rotate it 90 degrees on the other like

this this is going to block all of the

light there will not be no light should

be able to get through that if they're

true polarized filters a really cool

thing is you can purchase polarizing

filters for your strobes which means you

can create polarized light by putting

one of these polarized filters over your

strobe and it is only going to allow

light of a certain angle to escape now

these are both polarizing filters watch

what happens can you see my face in

there so I'm going to rotate these 90

degrees watch what happens

so now light should be able to come

through it's not a magic trick this

polarizing filters here in any event

that is a really quick crash course on

how polarisers work and how they block

the angle of light coming into the

if you enjoyed this video you might want

to check out my lighting crash course

I'll put a link in the description thank

you guys for watching and I'll see you

next time