October 3, 2011 • 36 mins
How does film work? What are the basic parts of a camera? How can you take a photo of a high-speed subject and get a clear picture? Tune in as Chris and Jonathan break down the tech behind slow motion and high speed photography.
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Episode Transcript
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Speaker 1 (00:00):
Brought to you by the reinvented two thousand twelve camera.
It's ready. Are you get in touch with technology with
tech stuff from how stuff works dot com. Hi there, kids,
and welcome to tech stuff. My name is Chris Pelette
(00:20):
and I'm an editor at how stuff works dot com.
Sitting directly opposite me, as usual, is senior writer Jonathan Strickland.
Let me take your picture added to the mixture. There
it is. I got you now, really nothing to it.
Anyone can do it. It's easy. And we all know
how today's podcast really lends itself to that quote. Yes,
(00:44):
today we wanted to talk about high speed photography and
slow motion. Both of these have to do with a
changing film speeds and shutter speeds and all this kind
of stuff. To really talk about how the stuff works,
we have to go a little bit more basic. We
have to actually talk about the principles behind photography and
(01:06):
how a camera works. And before we really get into this,
How stuff Works has dozens of great articles about photography,
including articles about how high speed photography works and how
burst photography works. Both of those were written by John Fuller.
But we also have how cameras work, how photographic film works.
So if you want to learn more than what you know,
(01:27):
we're going to kind of cover the basics. But if
you really want to know the true science and chemistry
and physics behind how cameras work, I highly recommend you
check out those articles because they will answer a lot
more questions. We're gonna try and kind of cover the
basics here. So so let's uh, let's talk about what
a camera does. It's seemed kind of silly to say
(01:51):
because we're most of us really familiar with cameras. And
by the way, I should point out also that we're
really focusing on film phil it was completely not on purpose. Um,
we're talking about film cameras mainly in this podcast as
opposed to digital. The two different methods. You know, you
get the you get a result that's similar using these
(02:12):
two methods. You know, you get an image of a
moment in time in both ways, but the actual mechanics
behind film versus digital are very different. So we're specifically
looking at it's gonna say, focus again looking at film
cameras because well, to to to try and cover both
would require a like a podcast that's twice as long
(02:34):
as what we normally do, and we only do that
for Google Plus well, UH cameras in general though, UM
and speaking of both film and digital, you're you're you're
using a series of UM devices to capture that image. There.
On both film and digital you of course you've got
(02:56):
a lens um and there is UH, the principle behind
it is to capture the image. On film, you're using
a a piece of essentially plastic celluloid to that's treated
with chemicals they captures that image, and in a digital
camera use an image sensor. UM. But you know, and
(03:18):
and there are some similarities of course. It It has
to do with how fast the camera is firing UM
and how much light you're letting in through the lens
um and after that they do differ considerably. So with
a with a film camera, you know, Chris was just
talking about it a second ago. But what you know,
(03:39):
the main the medium upon which you are capturing these
images is film, and film is really just a strip
of plastic that's been treated with UH, with chemicals that
are photoreactive. Yes, that means that the chemicals will undergo
some sort of change when exposed to light, so they
turned into monsters. If you've listened to our solar If
(03:59):
you listen to our Solar Panel episode, you know that
we have discovered materials that react when light hits it.
The photons from the light transfer energy to whatever that
medium is and you get a reaction. In this case,
the photons are able to change the chemical properties of
(04:19):
the stuff that's on this film. And I really get
into that would be diving deep into science. We do have,
like I said, the article on how photo, how film
photographic film works, and that explains it. But UM, to
be honest, if I were to try and go into
it right now, I'm sure I would mess it up
because you know, my my chemistry is only goes so far.
(04:42):
My chemistry food is weak chem But at any rate,
what this this stuff is designed so that when light
hits it, it has a chemical change. Then when you
treat it with other chemicals, that's what allows you to
create a negative image of whatever it was you were,
whatever light hit it. So this is why when you
(05:03):
have film, people say, you know, make sure you don't
expose it to light before before or after you take
a photo, because if you do, it's going to ruin
the image, right because um, the film is going to
record the light from the that that is coming to
it through the lens. So of course, when you put
(05:24):
the canister a film inside your camera and load your camera,
you close the door which blocks off any light. Um.
And then of course you have to advance the film
after you've taken a photo. If you if you've ever
exposed film more than once, double exposure, you get a
really bizarre effect. Yeah. Yeah, And it can be very
(05:45):
very cool if that's what you're going for. It can
also be really frustrating if you were trying to capture
one thing in particular and forgot to advance the film, right.
And and we've even seen that double exposures go into
uh the realm of people thinking that something supernatural roles
going on, because you do get kind of a ghostly
image if you double exposed film. Yeah. So there have
(06:06):
been times where people have had just a double exposure,
that's all it is, but because they didn't realize it
was a double exposure, they think, Wow, I took this
photo of my buddy Bob, and there's this ghostly face
that's appearing over his left shoulder that's so creepy, and
not forgetting that, oh before I took the photo of
Bob I took a photo of Liz. It's just that
(06:26):
Bob's photo was exposed over Liz's photo, and now Liz
looks like she's a ghost. Actually, I thought it was
because Bob worked at that leaky nuclear plants. Because we
took all those photos over that Indian burial ground. That
was a mistake we made anyway. Um uh. The the
the idea here is that the camera gives you a
(06:46):
very controlled way to expose that film to light. And
the way this works is that first you've got the lens,
and the lens is purpose is to direct light to
the film, So the lens is allowing light to pass through.
When light passes through a lens, that actually the speed
of the light changes. You know, speed of light is
(07:09):
a constant, but it's a constant that's based upon whatever
the medium it is that it's traveling through. For example, air, Yeah, air,
it's going to travel through it. Light travels through air
much more quickly than it will a lens. And the
curvature of the lens, the thickness of the lens, that's
all going to make the light travel at at slightly
different speeds. The point being that you focus all that
(07:31):
this light onto a point so that it exposes just
the right spot on the film. Now, behind that, you've
also got a device called the aperture. Now the aperture
is essentially a hole. It's a it's it's a disk
that can expand or contract and allow more or less
(07:52):
light to pass through the from the lens to the film.
So it's it's a barrier between the lens and the film.
And you adjust this in order to uh to really
kind of tweak your photo settings, like with a with
a manual camera, a manual single lens reflex camera or
SLR manual SLR uh by the way, in case you're curious,
(08:13):
for those of you who are only familiar with digital cameras,
a manual single lens reflex camera is not electric at all.
It's it uses chemicals and it uses mechanical little gears
and things, but there's there are no electric components necessarily
in a true manual single lens reflex or at least
you don't have to have any electronic I think that's
(08:36):
so in other words, it's kind of interesting because we
we take it for granted now with digital cameras. Right,
digital cameras, you have lots of electronic components, but with
a a an old manual single lens reflex, you're just
you're just turning little dials, which is advancing the film.
You might turn a little crank to rewind film, but
there's nothing necessarily electronic in it. Um. Of course, there
(08:58):
are hybrids that as well, But anyway, this the aperture
helps you determine how much light can enter through the lens.
And then you have something else called the shutter, and
the shutter determines how long the film is exposed to
that light. So if you were to take a photograph
(09:20):
with a shutter speed that is a you know, it
allows the shutter to be open longer, then your photo
is going to be a little more blurry, unless the
subject of your photo is incredibly still. So if the
camera is still and the subject is still, and you've
got a decent amount of lighting, and the shutter is
(09:40):
open longer, theoretically, as long as as long as the
light's not too great, you will actually get a very
clear image because it's it's really capturing that uh, that
moment um. Now, if something is moving, then you're gonna
get a blur. So if you've ever looked at some
nighttime photography especially or like city scapes where you can
(10:01):
see where traffic is moving through and it's like beautiful
red streaks on one side of the road and white
streaks on the other that you know, that's obviously the
traffic where cars are coming and going. That's usually using
a camera with a shutter speed where the shutters remaining
open longer. Sometimes it can be as long as you know,
minutes or or more, and that creates that streaking effect
(10:25):
because all that light is hitting the camera over an
extended time, so instead of seeing individual cars, you're seeing
these streaks. Yeah, this this has basically it's a combination
of things. It's a combination of the aperture setting that
you're using to expose the film, uh, the shutter speed,
and there are cameras that you can manually hold the
(10:47):
shutter open uh as long as you want to. It's
often better and creating the photos like Jonathan was just
talking about, where you leave it open for minutes to
have your camera on a tripod and use a cable release,
you know, just so that you don't nudge the camera
because otherwise you're going to uh jar the picture and
distort things. So yeah, it also has to do with
(11:08):
the speed of the film. And uh, it's funny because
that's sort of a misnomer. You know, there aren't little
canisters of film moving faster than others. It has to
do with the chemical properties actually the film. UM. And
again we're not going to get into the chemistry behind
it so much. UM. But uh, you know, depending on
the speed of the film, you would be able to
(11:30):
capture uh photos in darker environments or lighter environments. UM. Also,
the speed of the film has is depending on on
this the type of photography you're doing. If you're trying
to capture high or fast motion photography, you're gonna want
something that you can expose um to light more frequently,
(11:51):
like a higher speed film. UM. You know, you want
something that's going to to just from a very brief
exposure be able to capture an image. And and by exposure,
we're talking about exposing to light. You know, just keep
that in mind that that exposure has everything to do
with the amount of light and the duration of light
(12:11):
that hits that film. So a high speed film can
capture an image with light hitting it for a shorter
time frame. And we're talking fractions of a second. Here,
you know, when we talk about a short time frame,
we're talking really short. We're not talking like, oh, well,
you know a woman thousand two one, now you would
be able to take hundreds of photos in the mount
(12:32):
of time. It took me to say that depending on
the speed of the film and the shutter speed and
all of this kind of stuff. So so high speed
photography kind of leads us into this. High speed photography
is all about trying to capture, uh an image of
something that's moving at an incredible speed, something that that
is moving so fast that to the naked eye it
(12:55):
may be either a blur or perhaps even you know,
practically invisible because it's going so quickly. But you want
to be able to capture that moment in time so
that you can see a very distinct image. Well, this
is a challenge. You have to figure out how are
you going to do that, and a couple of different ways.
Perhaps I hesitate to say the easiest way, but perhaps
(13:17):
the simplest way is to set up your camera in
a perfectly dark room and you just leave the shutter open.
Because remember, even though the shutters open that film, if
there's no light, the film is not being exposed. So
you've got this film that's just sitting there. Nothing's happening
to it. It's not reacting chemically at all because there's
(13:39):
no light coming into the camera. You set up whatever
the thing is you want to take a photo of,
and then you have it timed out so that the
instant that thing happens, there is a flash of light
that is up and down in a fraction of us
(14:00):
can and just that fraction of a second is going
to be long enough for the light to go through
the camera and uh and to expose the film. Then
you could advance the frame and do it again. Now,
this is a very slow, painstaking process, and it requires
an incredible amount of timing, and there are a lot
of different ways of setting up a shot so that
(14:20):
the uh, the the light will trigger at the right moment.
Some of them are acoustically triggered so that there's a
noise and that noise causes the light to flash, which
automatically exposes the film in the camera. You don't have
to do anything to the camera at that point, right,
You're not pushing a button because the camera shutter is
already open. It's only after the light is flashed that
(14:42):
you have to advance the film so that you can
take another photo. Otherwise you're going to have a double exposure,
high speed double exposure on this this film, which I
think would look really weird. Um. So that's one way
you can do it. But of course, if you want
to take a high speed photo of something nature, for example,
the the an example that a lot of people use
(15:04):
as a hummingbird, because a hummingbird can beat its wings
so quickly that with most cameras, if you took a
picture of a hummingbird with a standard camera, it's gonna
look like a bird with two blurs next to it, right,
you won't be able to see the wings. Um. But
if you use a high speed camera where it's able
to move the shutter at a really fast rate, and
(15:25):
you have a pretty well lit environment, then you might
be able to capture an image of a hummingbird where
you've got its wings perhaps in the upper down position,
and you can get a really clear look at that bird.
But it does require that you have a camera that
can move that shutter speed at a really really fast rate,
and that you have a high speed film that's capable
(15:48):
of taking light for a incredibly brief exposure time and
convert that into an image. Yeah. You know, UM, if
you're a text a listener normally UM that we like
to get into the history of things. And I wouldn't
necessarily have have thought of high speed photography is I
(16:09):
would have thought it was a more modern UM, something
that was more modern phenomenon. But really the history of
high speed photography goes back just about as long as
the history of photography itself. UM. The first example that
I I read about UM from a a uh AN
article by Lincoln l Endelman, which was William Henry Fox
(16:34):
Talbot's uh trial where he basically exposed a piece of
the London Times newspaper that was on a wheel that
he attached it to, and he was using a wet
plate camera, which is basically a piece of glass that's
treated with chemicals rather than a film camera. Interesting. I
had never heard of that before there was one, and
(16:55):
heard of the camera obscura, which, by the way, you
can actually build one of those yourself if you or
wanted to, But I've never heard of the wet plate camera.
That's interesting. He uh and for a flash he was
using laden jars elimination from laden jars. This is like
the coolest camera ever. Yes, and cumbersome because you know,
you don't really take this thing out to go take
(17:18):
shots at the family on vacation. I'm out to the
high school football game. Let me carry my laden jars
and wet played caral with me. But but I need
the team's help setting this up. But he didn't manage
to get a readable photo of the newspaper at the
shutter speed of one of second unexposure speed. Let's say
(17:38):
that actually used. But you also probably remember Edward Mindbridge.
I remember the name. Yes, yes, he had a famous
experiment where um, he had set up a series of
cameras too, because there was a challenge. Um, you may
have heard of this guy, uh um Laden, I'm sorry, yeah,
I'm sorry. He may have heard of this guy at
(18:01):
Leland Stanford. He was the governor of California and he
was that that was the challenge was does a horse
pick up all four of its feet when it's running?
And he was the one my bridge and a lot
of people have seen this, uh seen this series of
photos where they proved that the horse was picking up
all four of its feet because he had a series
(18:22):
of cameras and that the horse was tripping it as
it ran by, and so each camera took photos a
different a different way of doing it, but they captured
a series of still photos because as the horse was
running by, it took you know, each camera in turn
took a still photo, and when you put them all together,
you get essentially slow motion of this horse running. Yeah,
(18:42):
and yes it does pick up all of its feet
when we'll get it, and we'll get into that in
a little bit, because of course the photography does lead
into cinematography. But before we do, I, before we jump
into that, I just wanted to mention one other kind
because I did mention burst photography when we were for
introducing this podcast, and that that John Fuller, Editor Extraordinaire
(19:05):
UH wrote the article on how burst photography works. First,
photography works on a similar principle of high speed photography. Now,
with high speed photography, you may be talking about taking
a single image and then setting up and taking another
single image, right right, That's like I'm pointing, I'm pointing
my camera at a hummingbird and I take one photo. Right.
(19:27):
The point of the high speed photography here is to
capture a very accurate still. Yeah, yeah, something that's going
to be. It's really used a lot in things like sports,
you know, trying to catchure, capture that dramatic moment where
the quarterback is releasing the hail Mary pass. I'm saying
that right, right, because I don't know anything about football
or you know, the people who absolutely positively have to
(19:48):
have that shot of the water balloon after the balloon
is broken and the water is still in the balloon shape,
but for the apple with the bullet through it. But
clearly this sort of that has to happen, this sort
of this sort of event is of course really hard
to capture on film, not just because of the nature
of the mechanics where you know, you've got to have
a camera with that proper shutter speed and film with
(20:10):
that proper um photochemical reaction speed. You also have to
have insane timing, and even by setting up an automated
system where everything's going to happen automatically, you know, as
soon as the event happens, it triggers the camera. Even
that is really difficult to do. So perhaps what if
you could have a camera that could shoot a series
(20:31):
of photos in a very short amount of time using
that same kind of principle. Well, that's what burst photography
is all about. These are cameras that have not just
the really fast shutter speed and not just the special
film that's going to to react quickly to a very
brief exposure, but also the ability to advance film rapidly
(20:54):
as you're taking photos. So with a burst photography camera,
it's pulling the film through very quickly and the shutter
is opening and closing, causing multiple exposures, but you're not
not a double exposure because you're you know, the films
being pulled through as you're as you're doing this so
that you can take a series of photos in a
brief amount of time, so like in a second or two,
(21:16):
you might take dozens or more photos. And this way, Uh,
the nice thing about this is that you can point
your camera at whatever the event is and just start
shooting photos until you're out of film and you have
a better chance of capturing that iconic moment you're after
as a photographer. Yeah, this is uh, this is one
(21:38):
of those times if if you haven't really done a
lot of work with people who are professional photographers, and
you might be going Last time I bought film, I
only had twenty four exposures on a roll. You can buy,
you know, if if you are interested in doing this, Uh,
you can buy whole magazines of film and you know,
(21:59):
attach them to the back of your camera where you
have a very very long roll. Or you can of
course make your own, uh, if you're so inclined and
are good in the dark. I used to have to
actually I was a newspaper report for a couple of years,
and um, you know, we'd have a big roll of
film and we'd load the magazines are are the cartridges ourselves.
And after a while you get pretty practiced at it.
(22:21):
But the first few times, uh, I wasted some film. Um,
but yeah, I mean so so this is sort of
one of those times when digital cameras sort of have
an advantage because now that we have bigger memory cards
and better digital photography. Um, the digital cameras are are
so much easier and more cost effective uh than than
(22:44):
film cameras in this regard. But the burst photography is amazing,
especially if you are you know, it allows you to
set up and have a much better shot at getting
your shot than than just just clicking and hoping that
you got it. Yeah. Yeah, Well this kind of leads us,
like I said, into cinematography, using film to capture images
(23:10):
in motion where you are going to play it back
so that you have the illusion of motions. So remember
film as in like I'm going to the movies to
watch a film is the the illusion of movement. And
it works because we capture lots of images and then
we put them in order and we, uh, we expose
(23:31):
our eyeballs to those images very in rapid succession, and
that creates the illusion of movement. So uh, the typical
film projector will play back film at a rate of
around twenty four frames per second, which means that every
second that passes, you're looking at twenty four images. Twenty
(23:53):
four photographs essentially, is what that is. So you're looking
at twenty four photographs in a row per second. Because
of that, it sort of gives this, It gives this
the illusion of the things that you're looking at are
really moving. It's not that you're looking at instances that
are put together. It's like it feels like a flowing
(24:13):
motion that has no no real interruption to it. I
think it's interesting to note too that when you're you're
saying twenty four frames per second. That's each frame is
a second. That seems pretty fast. But in my research
on high speed photography, I saw mentions of one eight
of a second. Um. Of course that would take a
(24:35):
whole lot of film. Yeah, but you know, it's it's
interesting to note that a second is reasonable enough to
give us an idea of motion and to create that
illusion for us. So, if you have a projector that's
going to play film back at a steady rate, so
let's let's go with the twenty four frames per second.
(24:56):
But you have a camera that can take that can
actually exp those film at a variable rate. That's where
you can start playing with the slow motion or fast
sped up motion on films. So if you've ever watched
an old movie where for comic effect, usually characters start
moving around really really quickly, you know, like there's a
(25:16):
chase scene and suddenly everyone's running at a speed that
doesn't really look natural. Yankety sacks may very well be
playing they did, and that's none of that, um, before
I get sued and uh, anyway, yeah, so this this
is playing with taking more images per second and then
playing it back at a steady speed. Um. Now, in
(25:39):
the old days, the good old days of filmmaking. Those
days you had cameras that were hand cranked, which meant
that you had a camera man or camera woman really
camera person um turning a crank that was squirrels possibly
turning a crank and hopefully a fairly consistent speed for
(26:00):
normal filming to advance the film through the camera as
it's being exposed to light. And the idea of being
that you want to turn the camera at a good
rate so that when you're projecting it back through the
projector it's a steady, smooth experience right when you are dB.
So yeah, so this this camera is not automated, it's
(26:21):
it's it's manpowered, and people are known to be you know, imperfect. Yeah,
not terribly consistent sometimes. Um so, yeah, if you turn
the crank faster than normal, you'd be exposing more film
in the same amount of time than you would if
you were going at your normal rate, which and when
you're playing it back, remember you're playing it back at
(26:43):
a h at a fixed rate. So if you've captured
more images in that amount of time then normal, then
you get the effect of slow motion, right because while
you've while you've captured maybe say, uh, you know, forty
eight images and then uh, you know, so you're looking
(27:04):
at forty eight images over the space of a of
two seconds. Uh. If it were played back at normal speed,
now you're looking at it at one second while everything
starts to slow down. That could be distracting. Yeah, so
this is a that's over cranking. Yes, it's when you're
cranking the camera faster than the projection playback speed. And
(27:27):
there's also under cranking, where you turn the crank slower
than the projection speed. This causes a sort of the
herky jerky fast motion stuff that you see, especially in
older films, where people start to are moving faster than
they normally could, and often it looks a little jumpy
because you're missing information. Right, the the the more amount
(27:49):
of time you have between when two images are taken
for something that's in motion, the less natural it's going
to look when when you're playing it back. Right. Because
so if I took a picture of Chris right now,
and then three seconds later took another picture, and three
seconds later took another picture, until I had, you know,
two photos, and I played them back at an at
(28:10):
a regular speed, uh, where it would look really really jerky,
you know, it wouldn't look natural at all and jerky,
not just because of the subject matter, but bump bump.
So it's only because I've been dried and cured. Right.
So you may have heard of the term of speed ramping.
(28:30):
Speed ramping is when you in the good old days,
it was done by accident, but today we do it
on purpose. Speed ramping is when you change the capture
rate of uh the film or video during a shoot,
and this is where you get those weird effects where
like it's often done in action sequences. For example, let's
(28:52):
say it's a fist fight between two characters and it
starts out normal, and one character starts to throw a punch,
and just as the characters throwing a punch, it switches
so it goes into slow motion, and then just as
the punch makes contact with the other person, it speeds
up again and it changes, uh the the capture rate,
but the playback rate remains constant. That's what we call
(29:14):
speed ramping. And there's certain directors who are infamous for
speed ramping. Um just you know, if you ever have
seen the movie three hundred or Watchmen, you know one
of the ones I'm talking about use a speed ramping
so much that it's distracting at times for some people.
Other people love it. I I personally think a little
(29:35):
goes a long way. I'm sorry anyway, that they're all
based on the same principle, the fact that if you
keep the playback rate steady and you change the capture rate,
you can you can make film appear to move slower
or faster. Um. Now, you could also play with the
playback rate. If you kept the capture rate the same
(29:58):
and you change the playback you would get the same effect,
right you would. You would either try and display more
images per second or fewer images per second than normal,
and you could get the same. Fact. This is a
lot easier to do in video than it isn't film. Sure, sure,
but it's funny to note again that like so many
other things in photography, that the key to slow motion
(30:22):
is high speed photography. Um. To to really get an
idea of what's happening and slow it down, you have
to capture many images so that you can you can
go from image to image at a slower rate and
really get a good idea of of the motion and
how things are transpiring. Uh in that image. Yeah, yeah,
(30:44):
if you if you take an uh a video of
something or a film of something, and it's at eight
thousand frames per second, and you play it back on
a twenty four frames per second projector, it's going to
take you a long time to get through. Like even
if you only shot for maybe five seconds, you know
that's gonna take you a long time to get through
(31:04):
those five seconds when you're playing it back at a
rate of twenty four frames per seconds. So then you
get this incredible slow motion effect where at times it
may look like nothing is even moving because everything is.
You know, you're capturing such tiny moments of time that
it's hard for us to detect changes until they are
dramatic changes. And this is where you can't. You can
(31:27):
see some of those really cool effects where like Chris
was saying, the water balloon, where you pop the balloon
and the water has retained the balloon shape for a
couple of a couple of split seconds, like moments in time,
and then you start to see it. You know, of course,
fall uh that that's we've seen some really cool footage
(31:50):
because of the this uh this technique, and you can
too if you go to the house stuff works dot
com site. We have a lot of clips from the
Discovery show Time warp Um, which was really popular a
couple of years ago because it showed extreme slow motion. Yeah,
using amazing high definition slow motion cameras that are taking
(32:13):
thousands of frames of footage per second and then playing
it back at normal speed. Yeah, and it's just it's
absolutely amazing. I can. I can watch them all the time,
you know, even the ones I've seen before, you know,
I can. I can go back and watch it just
because it's so fascinating how how all that works. I
love the ones where people get slapped and you just
see the face deform slowly. Wow, that's what happens. Whenever
(32:38):
I say anything to anyone that's insane. I'm I'm constantly can't. Yeah,
my face is hurting. I got slapped just before this podcast.
Actually yeah, but it was you that did it anyhow.
I never said that it was necessarily caused by someone else.
That's true, that's true. But yeah, I mean you can
you can. You can see at right now. They're they're
(33:01):
still up there. And I think when we post this
will probably I'm pretty sure there's a playlist we can
we can show people. Yeah. Um, yeah, that just it's
just a lot of fun to do that. And it's
a lot of fun to to fool around with high
speed photography just as that, you know, just as somebody
who is a hobbyist, um, to see what you can
do with it. And now, granted, if you want to
get like a really good high speed camera, this can
(33:24):
be an expensive hobby. Yeah. I mean, if you're talking
about the top of the line uh kind of set up,
then you're you're looking at thousands of dollars. So it's
not a cheap hobby necessarily, but it does really it's
really cool now and then you know, if you're if
you're really staging things too, um, yeah, of course, then
you have got the whole staging costs and stuff. Yeah,
(33:45):
and you're starting to talk about again because it is
a matter of uh, the camera detecting the image and
and getting synchronized with the the event that you're trying
to photograph, and um, you know you have to buy
the equipment to do that. We were talking about sound equipment.
They are setups that require you know that that the
sound will true cause the the camera to fire. And
(34:08):
you know this is again you're having to buy more gear. Um.
But it's it's it's fun if you can afford it.
It's pretty pretty interesting stuff. So yeah, this wraps up
at our discussion about high speed photography, slow motion cameras
in general film. Uh stuff is really really interesting. In fact,
it's so interesting to me that when I look at
(34:29):
the complexity of these devices. I mean, the principle is
pretty simple from a high concept point of view, but
when I start looking at the ingenuity that was required
to bring a camera into reality, Uh, I just it's
phenomenal to me. Again, It's one of those things where
we take it for granted now because they're everywhere. I mean,
(34:50):
we have cameras incorporated into practically every mobile device you
can think of, but the principles behind it, and it's
just it's just phenomenal, amazing that we figured us out. Yeah,
I mean think about we I mean, people way smarter
than I am. Well, you think about how the difference
in the early cameras that you know, degaro types and
and the wet plate type devices versus the tiny little
(35:14):
cameras in our smartphones, you know, shoes and everything else.
I don't want any shoe cameras. Let's let's not do that. Okay, alright, alright,
shoot people out there, don't put cameras in your shoes.
How about diamonds on the soldier shoes? How about self
lacing shoes? Hey, they just came out with those. Yeah,
(35:34):
well all right. Anyway, we're gonna wrap this up. So guys,
if you have any topics you would like us to
talk about, please let us know. You can let us
know through email. Our address is tech stuff at how
stuff Works dot com, or you can drop us a
line on Facebook or Twitter. Our handle there is text
stuffed H s W. Chris and I will talk to
(35:54):
you again really soon. Be sure to check out our
new video PI cast Stuff from the Future. Join how
Stuff Work staff as we explore the most promising and
perplexing possibilities of tomorrow. The House Stuff Works iPhone app
has arrived. Download it today on iTunes, brought to you
(36:17):
by the reinvented two thousand twelve camera. It's ready, are
you
Brought to you by the reinvented two thousand twelve camera.
It's ready. Are you get in touch with technology with
tech stuff from how stuff works dot com. Hi there, kids,
and welcome to tech stuff. My name is Chris Pelette
(00:20):
and I'm an editor at how stuff works dot com.
Sitting directly opposite me, as usual, is senior writer Jonathan Strickland.
Let me take your picture added to the mixture. There
it is. I got you now, really nothing to it.
Anyone can do it. It's easy. And we all know
how today's podcast really lends itself to that quote. Yes,
(00:44):
today we wanted to talk about high speed photography and
slow motion. Both of these have to do with a
changing film speeds and shutter speeds and all this kind
of stuff. To really talk about how the stuff works,
we have to go a little bit more basic. We
have to actually talk about the principles behind photography and
(01:06):
how a camera works. And before we really get into this,
How stuff Works has dozens of great articles about photography,
including articles about how high speed photography works and how
burst photography works. Both of those were written by John Fuller.
But we also have how cameras work, how photographic film works.
So if you want to learn more than what you know,
(01:27):
we're going to kind of cover the basics. But if
you really want to know the true science and chemistry
and physics behind how cameras work, I highly recommend you
check out those articles because they will answer a lot
more questions. We're gonna try and kind of cover the
basics here. So so let's uh, let's talk about what
a camera does. It's seemed kind of silly to say
(01:51):
because we're most of us really familiar with cameras. And
by the way, I should point out also that we're
really focusing on film phil it was completely not on purpose. Um,
we're talking about film cameras mainly in this podcast as
opposed to digital. The two different methods. You know, you
get the you get a result that's similar using these
(02:12):
two methods. You know, you get an image of a
moment in time in both ways, but the actual mechanics
behind film versus digital are very different. So we're specifically
looking at it's gonna say, focus again looking at film
cameras because well, to to to try and cover both
would require a like a podcast that's twice as long
(02:34):
as what we normally do, and we only do that
for Google Plus well, UH cameras in general though, UM
and speaking of both film and digital, you're you're you're
using a series of UM devices to capture that image. There.
On both film and digital you of course you've got
(02:56):
a lens um and there is UH, the principle behind
it is to capture the image. On film, you're using
a a piece of essentially plastic celluloid to that's treated
with chemicals they captures that image, and in a digital
camera use an image sensor. UM. But you know, and
(03:18):
and there are some similarities of course. It It has
to do with how fast the camera is firing UM
and how much light you're letting in through the lens
um and after that they do differ considerably. So with
a with a film camera, you know, Chris was just
talking about it a second ago. But what you know,
(03:39):
the main the medium upon which you are capturing these
images is film, and film is really just a strip
of plastic that's been treated with UH, with chemicals that
are photoreactive. Yes, that means that the chemicals will undergo
some sort of change when exposed to light, so they
turned into monsters. If you've listened to our solar If
(03:59):
you listen to our Solar Panel episode, you know that
we have discovered materials that react when light hits it.
The photons from the light transfer energy to whatever that
medium is and you get a reaction. In this case,
the photons are able to change the chemical properties of
(04:19):
the stuff that's on this film. And I really get
into that would be diving deep into science. We do have,
like I said, the article on how photo, how film
photographic film works, and that explains it. But UM, to
be honest, if I were to try and go into
it right now, I'm sure I would mess it up
because you know, my my chemistry is only goes so far.
(04:42):
My chemistry food is weak chem But at any rate,
what this this stuff is designed so that when light
hits it, it has a chemical change. Then when you
treat it with other chemicals, that's what allows you to
create a negative image of whatever it was you were,
whatever light hit it. So this is why when you
(05:03):
have film, people say, you know, make sure you don't
expose it to light before before or after you take
a photo, because if you do, it's going to ruin
the image, right because um, the film is going to
record the light from the that that is coming to
it through the lens. So of course, when you put
(05:24):
the canister a film inside your camera and load your camera,
you close the door which blocks off any light. Um.
And then of course you have to advance the film
after you've taken a photo. If you if you've ever
exposed film more than once, double exposure, you get a
really bizarre effect. Yeah. Yeah, And it can be very
(05:45):
very cool if that's what you're going for. It can
also be really frustrating if you were trying to capture
one thing in particular and forgot to advance the film, right.
And and we've even seen that double exposures go into
uh the realm of people thinking that something supernatural roles
going on, because you do get kind of a ghostly
image if you double exposed film. Yeah. So there have
(06:06):
been times where people have had just a double exposure,
that's all it is, but because they didn't realize it
was a double exposure, they think, Wow, I took this
photo of my buddy Bob, and there's this ghostly face
that's appearing over his left shoulder that's so creepy, and
not forgetting that, oh before I took the photo of
Bob I took a photo of Liz. It's just that
(06:26):
Bob's photo was exposed over Liz's photo, and now Liz
looks like she's a ghost. Actually, I thought it was
because Bob worked at that leaky nuclear plants. Because we
took all those photos over that Indian burial ground. That
was a mistake we made anyway. Um uh. The the
the idea here is that the camera gives you a
(06:46):
very controlled way to expose that film to light. And
the way this works is that first you've got the lens,
and the lens is purpose is to direct light to
the film, So the lens is allowing light to pass through.
When light passes through a lens, that actually the speed
of the light changes. You know, speed of light is
(07:09):
a constant, but it's a constant that's based upon whatever
the medium it is that it's traveling through. For example, air, Yeah, air,
it's going to travel through it. Light travels through air
much more quickly than it will a lens. And the
curvature of the lens, the thickness of the lens, that's
all going to make the light travel at at slightly
different speeds. The point being that you focus all that
(07:31):
this light onto a point so that it exposes just
the right spot on the film. Now, behind that, you've
also got a device called the aperture. Now the aperture
is essentially a hole. It's a it's it's a disk
that can expand or contract and allow more or less
(07:52):
light to pass through the from the lens to the film.
So it's it's a barrier between the lens and the film.
And you adjust this in order to uh to really
kind of tweak your photo settings, like with a with
a manual camera, a manual single lens reflex camera or
SLR manual SLR uh by the way, in case you're curious,
(08:13):
for those of you who are only familiar with digital cameras,
a manual single lens reflex camera is not electric at all.
It's it uses chemicals and it uses mechanical little gears
and things, but there's there are no electric components necessarily
in a true manual single lens reflex or at least
you don't have to have any electronic I think that's
(08:36):
so in other words, it's kind of interesting because we
we take it for granted now with digital cameras. Right,
digital cameras, you have lots of electronic components, but with
a a an old manual single lens reflex, you're just
you're just turning little dials, which is advancing the film.
You might turn a little crank to rewind film, but
there's nothing necessarily electronic in it. Um. Of course, there
(08:58):
are hybrids that as well, But anyway, this the aperture
helps you determine how much light can enter through the lens.
And then you have something else called the shutter, and
the shutter determines how long the film is exposed to
that light. So if you were to take a photograph
(09:20):
with a shutter speed that is a you know, it
allows the shutter to be open longer, then your photo
is going to be a little more blurry, unless the
subject of your photo is incredibly still. So if the
camera is still and the subject is still, and you've
got a decent amount of lighting, and the shutter is
(09:40):
open longer, theoretically, as long as as long as the
light's not too great, you will actually get a very
clear image because it's it's really capturing that uh, that
moment um. Now, if something is moving, then you're gonna
get a blur. So if you've ever looked at some
nighttime photography especially or like city scapes where you can
(10:01):
see where traffic is moving through and it's like beautiful
red streaks on one side of the road and white
streaks on the other that you know, that's obviously the
traffic where cars are coming and going. That's usually using
a camera with a shutter speed where the shutters remaining
open longer. Sometimes it can be as long as you know,
minutes or or more, and that creates that streaking effect
(10:25):
because all that light is hitting the camera over an
extended time, so instead of seeing individual cars, you're seeing
these streaks. Yeah, this this has basically it's a combination
of things. It's a combination of the aperture setting that
you're using to expose the film, uh, the shutter speed,
and there are cameras that you can manually hold the
(10:47):
shutter open uh as long as you want to. It's
often better and creating the photos like Jonathan was just
talking about, where you leave it open for minutes to
have your camera on a tripod and use a cable release,
you know, just so that you don't nudge the camera
because otherwise you're going to uh jar the picture and
distort things. So yeah, it also has to do with
(11:08):
the speed of the film. And uh, it's funny because
that's sort of a misnomer. You know, there aren't little
canisters of film moving faster than others. It has to
do with the chemical properties actually the film. UM. And
again we're not going to get into the chemistry behind
it so much. UM. But uh, you know, depending on
the speed of the film, you would be able to
(11:30):
capture uh photos in darker environments or lighter environments. UM. Also,
the speed of the film has is depending on on
this the type of photography you're doing. If you're trying
to capture high or fast motion photography, you're gonna want
something that you can expose um to light more frequently,
(11:51):
like a higher speed film. UM. You know, you want
something that's going to to just from a very brief
exposure be able to capture an image. And and by exposure,
we're talking about exposing to light. You know, just keep
that in mind that that exposure has everything to do
with the amount of light and the duration of light
(12:11):
that hits that film. So a high speed film can
capture an image with light hitting it for a shorter
time frame. And we're talking fractions of a second. Here,
you know, when we talk about a short time frame,
we're talking really short. We're not talking like, oh, well,
you know a woman thousand two one, now you would
be able to take hundreds of photos in the mount
(12:32):
of time. It took me to say that depending on
the speed of the film and the shutter speed and
all of this kind of stuff. So so high speed
photography kind of leads us into this. High speed photography
is all about trying to capture, uh an image of
something that's moving at an incredible speed, something that that
is moving so fast that to the naked eye it
(12:55):
may be either a blur or perhaps even you know,
practically invisible because it's going so quickly. But you want
to be able to capture that moment in time so
that you can see a very distinct image. Well, this
is a challenge. You have to figure out how are
you going to do that, and a couple of different ways.
Perhaps I hesitate to say the easiest way, but perhaps
(13:17):
the simplest way is to set up your camera in
a perfectly dark room and you just leave the shutter open.
Because remember, even though the shutters open that film, if
there's no light, the film is not being exposed. So
you've got this film that's just sitting there. Nothing's happening
to it. It's not reacting chemically at all because there's
(13:39):
no light coming into the camera. You set up whatever
the thing is you want to take a photo of,
and then you have it timed out so that the
instant that thing happens, there is a flash of light
that is up and down in a fraction of us
(14:00):
can and just that fraction of a second is going
to be long enough for the light to go through
the camera and uh and to expose the film. Then
you could advance the frame and do it again. Now,
this is a very slow, painstaking process, and it requires
an incredible amount of timing, and there are a lot
of different ways of setting up a shot so that
(14:20):
the uh, the the light will trigger at the right moment.
Some of them are acoustically triggered so that there's a
noise and that noise causes the light to flash, which
automatically exposes the film in the camera. You don't have
to do anything to the camera at that point, right,
You're not pushing a button because the camera shutter is
already open. It's only after the light is flashed that
(14:42):
you have to advance the film so that you can
take another photo. Otherwise you're going to have a double exposure,
high speed double exposure on this this film, which I
think would look really weird. Um. So that's one way
you can do it. But of course, if you want
to take a high speed photo of something nature, for example,
the the an example that a lot of people use
(15:04):
as a hummingbird, because a hummingbird can beat its wings
so quickly that with most cameras, if you took a
picture of a hummingbird with a standard camera, it's gonna
look like a bird with two blurs next to it, right,
you won't be able to see the wings. Um. But
if you use a high speed camera where it's able
to move the shutter at a really fast rate, and
(15:25):
you have a pretty well lit environment, then you might
be able to capture an image of a hummingbird where
you've got its wings perhaps in the upper down position,
and you can get a really clear look at that bird.
But it does require that you have a camera that
can move that shutter speed at a really really fast rate,
and that you have a high speed film that's capable
(15:48):
of taking light for a incredibly brief exposure time and
convert that into an image. Yeah. You know, UM, if
you're a text a listener normally UM that we like
to get into the history of things. And I wouldn't
necessarily have have thought of high speed photography is I
(16:09):
would have thought it was a more modern UM, something
that was more modern phenomenon. But really the history of
high speed photography goes back just about as long as
the history of photography itself. UM. The first example that
I I read about UM from a a uh AN
article by Lincoln l Endelman, which was William Henry Fox
(16:34):
Talbot's uh trial where he basically exposed a piece of
the London Times newspaper that was on a wheel that
he attached it to, and he was using a wet
plate camera, which is basically a piece of glass that's
treated with chemicals rather than a film camera. Interesting. I
had never heard of that before there was one, and
(16:55):
heard of the camera obscura, which, by the way, you
can actually build one of those yourself if you or
wanted to, But I've never heard of the wet plate camera.
That's interesting. He uh and for a flash he was
using laden jars elimination from laden jars. This is like
the coolest camera ever. Yes, and cumbersome because you know,
you don't really take this thing out to go take
(17:18):
shots at the family on vacation. I'm out to the
high school football game. Let me carry my laden jars
and wet played caral with me. But but I need
the team's help setting this up. But he didn't manage
to get a readable photo of the newspaper at the
shutter speed of one of second unexposure speed. Let's say
(17:38):
that actually used. But you also probably remember Edward Mindbridge.
I remember the name. Yes, yes, he had a famous
experiment where um, he had set up a series of
cameras too, because there was a challenge. Um, you may
have heard of this guy, uh um Laden, I'm sorry, yeah,
I'm sorry. He may have heard of this guy at
(18:01):
Leland Stanford. He was the governor of California and he
was that that was the challenge was does a horse
pick up all four of its feet when it's running?
And he was the one my bridge and a lot
of people have seen this, uh seen this series of
photos where they proved that the horse was picking up
all four of its feet because he had a series
(18:22):
of cameras and that the horse was tripping it as
it ran by, and so each camera took photos a
different a different way of doing it, but they captured
a series of still photos because as the horse was
running by, it took you know, each camera in turn
took a still photo, and when you put them all together,
you get essentially slow motion of this horse running. Yeah,
(18:42):
and yes it does pick up all of its feet
when we'll get it, and we'll get into that in
a little bit, because of course the photography does lead
into cinematography. But before we do, I, before we jump
into that, I just wanted to mention one other kind
because I did mention burst photography when we were for
introducing this podcast, and that that John Fuller, Editor Extraordinaire
(19:05):
UH wrote the article on how burst photography works. First,
photography works on a similar principle of high speed photography. Now,
with high speed photography, you may be talking about taking
a single image and then setting up and taking another
single image, right right, That's like I'm pointing, I'm pointing
my camera at a hummingbird and I take one photo. Right.
(19:27):
The point of the high speed photography here is to
capture a very accurate still. Yeah, yeah, something that's going
to be. It's really used a lot in things like sports,
you know, trying to catchure, capture that dramatic moment where
the quarterback is releasing the hail Mary pass. I'm saying
that right, right, because I don't know anything about football
or you know, the people who absolutely positively have to
(19:48):
have that shot of the water balloon after the balloon
is broken and the water is still in the balloon shape,
but for the apple with the bullet through it. But
clearly this sort of that has to happen, this sort
of this sort of event is of course really hard
to capture on film, not just because of the nature
of the mechanics where you know, you've got to have
a camera with that proper shutter speed and film with
(20:10):
that proper um photochemical reaction speed. You also have to
have insane timing, and even by setting up an automated
system where everything's going to happen automatically, you know, as
soon as the event happens, it triggers the camera. Even
that is really difficult to do. So perhaps what if
you could have a camera that could shoot a series
(20:31):
of photos in a very short amount of time using
that same kind of principle. Well, that's what burst photography
is all about. These are cameras that have not just
the really fast shutter speed and not just the special
film that's going to to react quickly to a very
brief exposure, but also the ability to advance film rapidly
(20:54):
as you're taking photos. So with a burst photography camera,
it's pulling the film through very quickly and the shutter
is opening and closing, causing multiple exposures, but you're not
not a double exposure because you're you know, the films
being pulled through as you're as you're doing this so
that you can take a series of photos in a
brief amount of time, so like in a second or two,
(21:16):
you might take dozens or more photos. And this way, Uh,
the nice thing about this is that you can point
your camera at whatever the event is and just start
shooting photos until you're out of film and you have
a better chance of capturing that iconic moment you're after
as a photographer. Yeah, this is uh, this is one
(21:38):
of those times if if you haven't really done a
lot of work with people who are professional photographers, and
you might be going Last time I bought film, I
only had twenty four exposures on a roll. You can buy,
you know, if if you are interested in doing this, Uh,
you can buy whole magazines of film and you know,
(21:59):
attach them to the back of your camera where you
have a very very long roll. Or you can of
course make your own, uh, if you're so inclined and
are good in the dark. I used to have to
actually I was a newspaper report for a couple of years,
and um, you know, we'd have a big roll of
film and we'd load the magazines are are the cartridges ourselves.
And after a while you get pretty practiced at it.
(22:21):
But the first few times, uh, I wasted some film. Um,
but yeah, I mean so so this is sort of
one of those times when digital cameras sort of have
an advantage because now that we have bigger memory cards
and better digital photography. Um, the digital cameras are are
so much easier and more cost effective uh than than
(22:44):
film cameras in this regard. But the burst photography is amazing,
especially if you are you know, it allows you to
set up and have a much better shot at getting
your shot than than just just clicking and hoping that
you got it. Yeah. Yeah, Well this kind of leads us,
like I said, into cinematography, using film to capture images
(23:10):
in motion where you are going to play it back
so that you have the illusion of motions. So remember
film as in like I'm going to the movies to
watch a film is the the illusion of movement. And
it works because we capture lots of images and then
we put them in order and we, uh, we expose
(23:31):
our eyeballs to those images very in rapid succession, and
that creates the illusion of movement. So uh, the typical
film projector will play back film at a rate of
around twenty four frames per second, which means that every
second that passes, you're looking at twenty four images. Twenty
(23:53):
four photographs essentially, is what that is. So you're looking
at twenty four photographs in a row per second. Because
of that, it sort of gives this, It gives this
the illusion of the things that you're looking at are
really moving. It's not that you're looking at instances that
are put together. It's like it feels like a flowing
(24:13):
motion that has no no real interruption to it. I
think it's interesting to note too that when you're you're
saying twenty four frames per second. That's each frame is
a second. That seems pretty fast. But in my research
on high speed photography, I saw mentions of one eight
of a second. Um. Of course that would take a
(24:35):
whole lot of film. Yeah, but you know, it's it's
interesting to note that a second is reasonable enough to
give us an idea of motion and to create that
illusion for us. So, if you have a projector that's
going to play film back at a steady rate, so
let's let's go with the twenty four frames per second.
(24:56):
But you have a camera that can take that can
actually exp those film at a variable rate. That's where
you can start playing with the slow motion or fast
sped up motion on films. So if you've ever watched
an old movie where for comic effect, usually characters start
moving around really really quickly, you know, like there's a
(25:16):
chase scene and suddenly everyone's running at a speed that
doesn't really look natural. Yankety sacks may very well be
playing they did, and that's none of that, um, before
I get sued and uh, anyway, yeah, so this this
is playing with taking more images per second and then
playing it back at a steady speed. Um. Now, in
(25:39):
the old days, the good old days of filmmaking. Those
days you had cameras that were hand cranked, which meant
that you had a camera man or camera woman really
camera person um turning a crank that was squirrels possibly
turning a crank and hopefully a fairly consistent speed for
(26:00):
normal filming to advance the film through the camera as
it's being exposed to light. And the idea of being
that you want to turn the camera at a good
rate so that when you're projecting it back through the
projector it's a steady, smooth experience right when you are dB.
So yeah, so this this camera is not automated, it's
(26:21):
it's it's manpowered, and people are known to be you know, imperfect. Yeah,
not terribly consistent sometimes. Um so, yeah, if you turn
the crank faster than normal, you'd be exposing more film
in the same amount of time than you would if
you were going at your normal rate, which and when
you're playing it back, remember you're playing it back at
(26:43):
a h at a fixed rate. So if you've captured
more images in that amount of time then normal, then
you get the effect of slow motion, right because while
you've while you've captured maybe say, uh, you know, forty
eight images and then uh, you know, so you're looking
(27:04):
at forty eight images over the space of a of
two seconds. Uh. If it were played back at normal speed,
now you're looking at it at one second while everything
starts to slow down. That could be distracting. Yeah, so
this is a that's over cranking. Yes, it's when you're
cranking the camera faster than the projection playback speed. And
(27:27):
there's also under cranking, where you turn the crank slower
than the projection speed. This causes a sort of the
herky jerky fast motion stuff that you see, especially in
older films, where people start to are moving faster than
they normally could, and often it looks a little jumpy
because you're missing information. Right, the the the more amount
(27:49):
of time you have between when two images are taken
for something that's in motion, the less natural it's going
to look when when you're playing it back. Right. Because
so if I took a picture of Chris right now,
and then three seconds later took another picture, and three
seconds later took another picture, until I had, you know,
two photos, and I played them back at an at
(28:10):
a regular speed, uh, where it would look really really jerky,
you know, it wouldn't look natural at all and jerky,
not just because of the subject matter, but bump bump.
So it's only because I've been dried and cured. Right.
So you may have heard of the term of speed ramping.
(28:30):
Speed ramping is when you in the good old days,
it was done by accident, but today we do it
on purpose. Speed ramping is when you change the capture
rate of uh the film or video during a shoot,
and this is where you get those weird effects where
like it's often done in action sequences. For example, let's
(28:52):
say it's a fist fight between two characters and it
starts out normal, and one character starts to throw a punch,
and just as the characters throwing a punch, it switches
so it goes into slow motion, and then just as
the punch makes contact with the other person, it speeds
up again and it changes, uh the the capture rate,
but the playback rate remains constant. That's what we call
(29:14):
speed ramping. And there's certain directors who are infamous for
speed ramping. Um just you know, if you ever have
seen the movie three hundred or Watchmen, you know one
of the ones I'm talking about use a speed ramping
so much that it's distracting at times for some people.
Other people love it. I I personally think a little
(29:35):
goes a long way. I'm sorry anyway, that they're all
based on the same principle, the fact that if you
keep the playback rate steady and you change the capture rate,
you can you can make film appear to move slower
or faster. Um. Now, you could also play with the
playback rate. If you kept the capture rate the same
(29:58):
and you change the playback you would get the same effect,
right you would. You would either try and display more
images per second or fewer images per second than normal,
and you could get the same. Fact. This is a
lot easier to do in video than it isn't film. Sure, sure,
but it's funny to note again that like so many
other things in photography, that the key to slow motion
(30:22):
is high speed photography. Um. To to really get an
idea of what's happening and slow it down, you have
to capture many images so that you can you can
go from image to image at a slower rate and
really get a good idea of of the motion and
how things are transpiring. Uh in that image. Yeah, yeah,
(30:44):
if you if you take an uh a video of
something or a film of something, and it's at eight
thousand frames per second, and you play it back on
a twenty four frames per second projector, it's going to
take you a long time to get through. Like even
if you only shot for maybe five seconds, you know
that's gonna take you a long time to get through
(31:04):
those five seconds when you're playing it back at a
rate of twenty four frames per seconds. So then you
get this incredible slow motion effect where at times it
may look like nothing is even moving because everything is.
You know, you're capturing such tiny moments of time that
it's hard for us to detect changes until they are
dramatic changes. And this is where you can't. You can
(31:27):
see some of those really cool effects where like Chris
was saying, the water balloon, where you pop the balloon
and the water has retained the balloon shape for a
couple of a couple of split seconds, like moments in time,
and then you start to see it. You know, of course,
fall uh that that's we've seen some really cool footage
(31:50):
because of the this uh this technique, and you can
too if you go to the house stuff works dot
com site. We have a lot of clips from the
Discovery show Time warp Um, which was really popular a
couple of years ago because it showed extreme slow motion. Yeah,
using amazing high definition slow motion cameras that are taking
(32:13):
thousands of frames of footage per second and then playing
it back at normal speed. Yeah, and it's just it's
absolutely amazing. I can. I can watch them all the time,
you know, even the ones I've seen before, you know,
I can. I can go back and watch it just
because it's so fascinating how how all that works. I
love the ones where people get slapped and you just
see the face deform slowly. Wow, that's what happens. Whenever
(32:38):
I say anything to anyone that's insane. I'm I'm constantly can't. Yeah,
my face is hurting. I got slapped just before this podcast.
Actually yeah, but it was you that did it anyhow.
I never said that it was necessarily caused by someone else.
That's true, that's true. But yeah, I mean you can
you can. You can see at right now. They're they're
(33:01):
still up there. And I think when we post this
will probably I'm pretty sure there's a playlist we can
we can show people. Yeah. Um, yeah, that just it's
just a lot of fun to do that. And it's
a lot of fun to to fool around with high
speed photography just as that, you know, just as somebody
who is a hobbyist, um, to see what you can
do with it. And now, granted, if you want to
get like a really good high speed camera, this can
(33:24):
be an expensive hobby. Yeah. I mean, if you're talking
about the top of the line uh kind of set up,
then you're you're looking at thousands of dollars. So it's
not a cheap hobby necessarily, but it does really it's
really cool now and then you know, if you're if
you're really staging things too, um, yeah, of course, then
you have got the whole staging costs and stuff. Yeah,
(33:45):
and you're starting to talk about again because it is
a matter of uh, the camera detecting the image and
and getting synchronized with the the event that you're trying
to photograph, and um, you know you have to buy
the equipment to do that. We were talking about sound equipment.
They are setups that require you know that that the
sound will true cause the the camera to fire. And
(34:08):
you know this is again you're having to buy more gear. Um.
But it's it's it's fun if you can afford it.
It's pretty pretty interesting stuff. So yeah, this wraps up
at our discussion about high speed photography, slow motion cameras
in general film. Uh stuff is really really interesting. In fact,
it's so interesting to me that when I look at
(34:29):
the complexity of these devices. I mean, the principle is
pretty simple from a high concept point of view, but
when I start looking at the ingenuity that was required
to bring a camera into reality, Uh, I just it's
phenomenal to me. Again, It's one of those things where
we take it for granted now because they're everywhere. I mean,
(34:50):
we have cameras incorporated into practically every mobile device you
can think of, but the principles behind it, and it's
just it's just phenomenal, amazing that we figured us out. Yeah,
I mean think about we I mean, people way smarter
than I am. Well, you think about how the difference
in the early cameras that you know, degaro types and
and the wet plate type devices versus the tiny little
(35:14):
cameras in our smartphones, you know, shoes and everything else.
I don't want any shoe cameras. Let's let's not do that. Okay, alright, alright,
shoot people out there, don't put cameras in your shoes.
How about diamonds on the soldier shoes? How about self
lacing shoes? Hey, they just came out with those. Yeah,
(35:34):
well all right. Anyway, we're gonna wrap this up. So guys,
if you have any topics you would like us to
talk about, please let us know. You can let us
know through email. Our address is tech stuff at how
stuff Works dot com, or you can drop us a
line on Facebook or Twitter. Our handle there is text
stuffed H s W. Chris and I will talk to
(35:54):
you again really soon. Be sure to check out our
new video PI cast Stuff from the Future. Join how
Stuff Work staff as we explore the most promising and
perplexing possibilities of tomorrow. The House Stuff Works iPhone app
has arrived. Download it today on iTunes, brought to you
(36:17):
by the reinvented two thousand twelve camera. It's ready, are
you
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Karah Preiss
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