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