Speaker 1: Brought to you by the reinvented two thousand twelve Camray.
Speaker 1: It's ready. Are you get in touch with technology with
Speaker 1: tex Stuff from how stuff works dot com. Hello, and
Speaker 1: welcome to tex Stuff. My name is Chris Poulette and
Speaker 1: I am an editor at how stuff works dot com,
Speaker 1: sitting in a cross froom me as usual as senior
Speaker 1: writer Jonathan Strickland. Psychics can see the color of time.
Speaker 1: It's blue. Okay, I'd kind of love to know what
Speaker 1: what that one's from. I'll tell you. I'll tell you
Speaker 1: after the show if you remind me, alright, I always
Speaker 1: say that I'll tell you, and I never tell you
Speaker 1: because I always forget by the time we're done recording.
Speaker 1: Tell me what there's the trivia for you, folks. So
Speaker 1: today we thought we would look at something. Actually, it
Speaker 1: was Chris's suggestion that we look into this particular topic,
Speaker 1: which was the the topic of image sensors and what
Speaker 1: they do and what the two main types of image sensors,
Speaker 1: how they are different from one another, and uh, and
Speaker 1: I thought it was a great idea. It's also a
Speaker 1: fairly complex topic. We do have an article on how
Speaker 1: stuff works dot com that says what is the difference
Speaker 1: between c c D and CMO s image sensors in
Speaker 1: a digital camera. And that's really what we're gonna be
Speaker 1: talking about here. Um. So that there is an article
Speaker 1: on the site, and it's a nice short article if
Speaker 1: you want a quick overview, but we're gonna go into
Speaker 1: some detail a little bit in this podcast. And really
Speaker 1: the first thing you need to know is that an
Speaker 1: image sensor is it's taking the place of film, right, Yes,
Speaker 1: that's correct. Yeah, a long and long time ago in
Speaker 1: a galaxy that happens to be right here where we're sitting.
Speaker 1: We did a podcast on the megapixel myth um. I
Speaker 1: think a lot of people equate uh numbers with a
Speaker 1: way too yeah, with quality, and they say, oh, well,
Speaker 1: I've got a twelve megapixel camera that's obviously better than
Speaker 1: that six make a pixel camera I used to own. Well,
Speaker 1: it depends on what you're doing with the photo. It
Speaker 1: also depends on again the other qualities of that camera, right,
Speaker 1: and image sensors have a lot more to do with
Speaker 1: the quality of the photo. But in a way it
Speaker 1: really depends because again this uh there, there's this this
Speaker 1: idea that there are two different kinds which kind is better.
Speaker 1: It depends on what you're doing with that, what are
Speaker 1: you taking photos of? UM and uh, as it turns out,
Speaker 1: they're they're not really better than one another. Inherently, they're
Speaker 1: they're better than one another for specific applications of the
Speaker 1: photographic technology, and the quality of the two sensors is
Speaker 1: constantly getting closer and closer, so that the things that
Speaker 1: one sensor does better than the other start to become
Speaker 1: less distinct over time because the technology is improving on
Speaker 1: both sides simultaneously. Uh. If we were to go back
Speaker 1: a little bit to the early days of digital cameras,
Speaker 1: the distinction was was clear. You know, you would say that, well,
Speaker 1: a professional photographer would more likely have a cc D
Speaker 1: image sensor in his or her camera c c D
Speaker 1: meaning charge coupled device, charge coupled device, that's that's one
Speaker 1: of the two types. And someone who has say a
Speaker 1: relatively inexpensive of course, back in the early day of
Speaker 1: digital cameras, that was definitely relatively eight billion dollars, only
Speaker 1: a thousand, princely going back to that a thousand dollars
Speaker 1: as opposed to say eight thousand dollars. But a person
Speaker 1: holding one of those cameras might have a CMOS or
Speaker 1: a complementary metal ox side semiconductor image sensory. They come
Speaker 1: up and say, that's a wonderful shirt you're wearing today.
Speaker 1: That's such a great picture you've taken. Have you lost weight? No,
Speaker 1: it's not that kind of complimentary. I have a whole
Speaker 1: joke about that, but I'm going to everybody because we've
Speaker 1: already said the punchline. Anyway, these are the two different sensors,
Speaker 1: and they do go about capturing data a different way.
Speaker 1: Let's let's go into the basic way a camera captures
Speaker 1: an image. I'm going to talk about still camera here. Okay,
Speaker 1: so we're talking about cameras in general, not necessarily film
Speaker 1: or digital. Right, So, in general, what happens is you've
Speaker 1: got a camera and you're pointing it at something that
Speaker 1: you want to take a photo of. Light is coming
Speaker 1: towards you. It's reflecting off of the the subject of
Speaker 1: your photo. If light we're not reflecting off the subject
Speaker 1: of your photo, it would either mean you were in
Speaker 1: total darkness, in which case taking a photo is not
Speaker 1: very helpful, or you're taking a picture of a black
Speaker 1: hole because not even light can escape it. That being said,
Speaker 1: they're actually looking at making a physical picture of a
Speaker 1: black hole using radio telescopes, which is so cool. That's
Speaker 1: a tangent. Anyway, so light is coming from the subject
Speaker 1: is some We should do a full podcast just on that.
Speaker 1: But anyway, lights coming from from the subject towards the
Speaker 1: camera and uh, and the light passes through the lens.
Speaker 1: The purpose of the lens is to focus that light
Speaker 1: toward a specific point within the camera. It moves through
Speaker 1: the aperture, which is the opening behind the lens that
Speaker 1: allows light to pass through. There's a shutter that's there
Speaker 1: behind the aperture which actually directs the light up towards
Speaker 1: the view finder. For the old style cameras, you know,
Speaker 1: the ones that don't have the you know, you're not
Speaker 1: looking at a screen on the back, you're looking actually
Speaker 1: through a view finder. Well, that light gets directed up
Speaker 1: by a mirror that's essentially attached to the shutter that
Speaker 1: makes the light go up inside the camera. Then it
Speaker 1: hits a prism which inverts the light. Because you may
Speaker 1: not know this, but the light the image that's coming in.
Speaker 1: That's saying the sensor is actually upside down from our perspective. Gasp.
Speaker 1: So if you didn't have that prism there, the subject
Speaker 1: you're looking at would be upside down. It would be
Speaker 1: like everything you're taking photos of was in Australia, unless
Speaker 1: you're Australian, in which case it's all in Detroit. So
Speaker 1: that's that's way. If you're wondering why there's all these
Speaker 1: giant car factories in Australia, it's not. It's just because
Speaker 1: you didn't have that there, right, Um, Okay, that's a
Speaker 1: terrible joke, but no, the prism does invert the light,
Speaker 1: so otherwise again upside down. So when you press the
Speaker 1: button to capture an image, the shutter, the shutter release exactly,
Speaker 1: the shutter, the shutter moves out of the way. Instead
Speaker 1: of the light hitting that mirror and going up to
Speaker 1: the prism and inverting the light hits either film in
Speaker 1: a film camera or an image sensor in a digital camera.
Speaker 1: So really the shutter just moves out of the way
Speaker 1: and then the light hits the sensor and then you're
Speaker 1: good to go. It's a little different with the digital
Speaker 1: cameras that are out right now, but that's in general
Speaker 1: how the process works. The basics. Yeah, now, and with
Speaker 1: cameras now, light maybe hitting the sensor constantly, and the
Speaker 1: shutter itself is not a physical shutter. It's just the
Speaker 1: way that the sensory captures data. And we'll talk about
Speaker 1: that when we get to that point. There are two
Speaker 1: different major types of shutters that we can talk about.
Speaker 1: So that's the general process. Now, with film, it's a
Speaker 1: chemical process. Light hits the film and then some chemical
Speaker 1: reactions take place, and that's what allows you to capture
Speaker 1: an image. Right. With image sensors, it's not chemical, it's electrical. Right,
Speaker 1: you're converting light energy into an electronic signal, yes, which
Speaker 1: then you're gonna want to store to some medium. Yes, uh,
Speaker 1: you know, typically some kind of flash memory device, depending
Speaker 1: on on what kind of camera you have. You know,
Speaker 1: there were some I think that that stored on CD,
Speaker 1: so you know, your mileage may vary, but in general,
Speaker 1: some sort of flash device on on today's cameras. Yeah,
Speaker 1: the old digital camcorders could record on on different kinds
Speaker 1: of media and so, and digital camcorders are working under
Speaker 1: the same general principles as digital still cameras, with some
Speaker 1: you know, other differences, but we'll talk about that. Like
Speaker 1: I said, so now we get into the differences between
Speaker 1: the two major types of sensors, the charge coupled device
Speaker 1: and the complementary metal oxide semiconductor. So we're just gonna
Speaker 1: go do cc D and CMOS from here on out,
Speaker 1: I think, otherwise I'm just going to have tongue twisters
Speaker 1: for the rest of the podcast. Yes, well, I just
Speaker 1: wanted to make sure that people knew what it what
Speaker 1: it stood for, obviously very important. So in in a
Speaker 1: CCD sensor, every single pixel now, pixel, remember, is a
Speaker 1: point of light. An image is made up of pixels,
Speaker 1: millions of pixels. That's where the megapixel comes from. Right,
Speaker 1: So a twelve megapixel camera is going to take twelve
Speaker 1: megapixels worth of pixels and within the dimensions of that image,
Speaker 1: whereas an eight megapixel camera will use fewer pixels for
Speaker 1: that same size. Right. But and that's where our idea
Speaker 1: about resolution comes in. Sometimes you hear people talk about
Speaker 1: a low resolution image, it may be that it's got
Speaker 1: fewer pixels in that image so that you can actually
Speaker 1: start seeing if if the pixels are large enough and
Speaker 1: few enough, you can start seeing the borders from one
Speaker 1: pixel to the next. It's not very smooth, it's almost jagged. Well, yeah,
Speaker 1: I mean that this is the benefit of having a
Speaker 1: high megapixel camera. If you shoot it high quality, then
Speaker 1: you are capturing more more pixels for a specific region
Speaker 1: of the image, and you can you can render that
Speaker 1: photo in a larger format. Um because when you shrink,
Speaker 1: when you when you compress the size of a photo
Speaker 1: and reduce it in size um, the computer is able to,
Speaker 1: you know, throw out unnecessary information and that the image
Speaker 1: still is pretty good looking. When you try to increase
Speaker 1: the size, the computer has to sort of guess on
Speaker 1: you know, pixel by pixel basis. Well, I mean, this
Speaker 1: color is sort of a brown color. It looks like
Speaker 1: I could throw something else in here similar. And that's
Speaker 1: why when you increase the size of a photo, a
Speaker 1: digital photo, that it starts to look kind of jaggedy
Speaker 1: and rough because the computer is having to guess at
Speaker 1: what that information is. So if you take a ten
Speaker 1: megapixel photo and shrink it down, it's it's gonna look
Speaker 1: pretty good. But if you try to take a two
Speaker 1: megapixel photo and blow it up, it's not gonna be
Speaker 1: so pretty. Yeah. If you think about it like a puzzle,
Speaker 1: Let's say that you have a puzzle that has four
Speaker 1: pieces to it, well, then you're gonna be able to
Speaker 1: see the division of those those four pieces very clearly.
Speaker 1: If it has four million pieces, then it's each of
Speaker 1: those pieces are individually much tinier than those for giant ones.
Speaker 1: And so the other issue is that the larger you
Speaker 1: blow something up, if it's if it doesn't have enough
Speaker 1: mega pixels in it, not megapixels, but enough pixels, then
Speaker 1: you're gonna start to notice. But that being said, uh,
Speaker 1: the general digital cameras that are out there for the
Speaker 1: consumer market and the general way the consumers use digital cameras,
Speaker 1: megapixels really don't matter because most of us are not
Speaker 1: blowing images up to poster size. Most of us are
Speaker 1: using them for online photo albums. We might print a
Speaker 1: few out, but usually eight by ten tends to be
Speaker 1: about the largest because most people don't have printers capable
Speaker 1: of printing at a larger size, take it to somebody
Speaker 1: to have it printed. It's kind of expensive, so a poster.
Speaker 1: Most of us don't do that, So most of us
Speaker 1: don't need to worry about megapixels at this point. Professional photographers,
Speaker 1: it's a different story. So cc D sensor each of
Speaker 1: those pixels has a charge. The photons that are coming
Speaker 1: in and hitting that image sensor are being transferred from
Speaker 1: from a light inner g from photons into electrons. Now UH,
Speaker 1: they have UH there's an output node with a c
Speaker 1: c D sensor where that is converted into voltage. It's
Speaker 1: buffered and then sent to a different part of the
Speaker 1: camera so that it will become an analog signal. So
Speaker 1: a c c D sensor it's a very it's a
Speaker 1: very UH specific device that doesn't it doesn't have a
Speaker 1: lot of other functionality to it apart from the fact
Speaker 1: that it's taking in light and converting it into voltage. UH.
Speaker 1: Now the pixel is completely devoted to capturing light and
Speaker 1: it has a very uniform output. So the that's that's
Speaker 1: sort of where the the idea of CCD being high
Speaker 1: quality came from. UH. It was very good at capturing
Speaker 1: the true essence of whatever it is you're pointing your
Speaker 1: camera at. You don't have to have you don't have
Speaker 1: to worry about low lighting effects that kind of stuff,
Speaker 1: or or having uh an image turn out too grainy
Speaker 1: if the light is too low, which can happen with
Speaker 1: CMOS images, particularly from a few years ago. It's a
Speaker 1: depending on where you know where the manufacturer for your
Speaker 1: camera got the c m O S sensor. Uh, you
Speaker 1: might not have as big an issue taking low lighting
Speaker 1: up images. But if you've ever used a digital camera
Speaker 1: in a you know, either a dark or just a
Speaker 1: dem environment, and you look like this just doesn't look good. Now,
Speaker 1: when I take a photo outside in the middle of
Speaker 1: the daytime, it looks gorgeous, beautiful colors, very very distinct um.
Speaker 1: That's part of the problem is that the CMOS sensor
Speaker 1: captures it in a different way. In that case, every
Speaker 1: single pixel has its own charge to voltage conversion. The
Speaker 1: c c D it's doing all of the pixels at once,
Speaker 1: and c m OS it's doing each pixel individually. And
Speaker 1: then the sensor itself has other elements added to it
Speaker 1: that the c c D sensor does not have. Remember
Speaker 1: we said c c D kind of offloads the information
Speaker 1: once it's been converted into electrical impulses to other chips, right, Well,
Speaker 1: those elements are actually on a CMO S sensor. So
Speaker 1: it's got amplifiers, it's got digitization circuits, so it's actually
Speaker 1: converting the electricity into bits on the sensor itself. It's
Speaker 1: got noise reduction capabilities. And so that means that it
Speaker 1: actually speeds up the process and it decreases the amount
Speaker 1: of space you need within a camera because all of
Speaker 1: those elements are found on a single chip as opposed
Speaker 1: to having dedicated chips for these these specific functions. Unfortunately,
Speaker 1: also reduces the amount of space it has for image
Speaker 1: capture because all that stuff is on the same chip. Yes,
Speaker 1: so that that you know, that's a downside of it, Yes,
Speaker 1: so you that was one of the arguments again early on,
Speaker 1: was that c c D cameras could take sharper photos
Speaker 1: than CMOS cameras, and that you know, it's almost there
Speaker 1: was also an expense issue, right, c c D image
Speaker 1: sensors tend to be more expensive than c MS ones CMOS.
Speaker 1: The process of manufacturer got so efficient that the price
Speaker 1: started to come down, and that that's why those are
Speaker 1: the sort of image sensors that you find in things
Speaker 1: like smartphones. You know, smartphones that have cameras tend to
Speaker 1: have CMOS sensors in them. They take up less space,
Speaker 1: they put out less heat, they take less energy to
Speaker 1: run um and they're very fast. So those are all
Speaker 1: the qualities that people who are having a who wants
Speaker 1: something in a nice slim form factor or if that's
Speaker 1: what's important to them. So yeah, CCDC image sensor might
Speaker 1: take a sharper quality photo in certain situations, but it's
Speaker 1: also going to require a larger form factor, and it
Speaker 1: does take more energy to run, and that that energy
Speaker 1: is going to also mean more heat because as we know,
Speaker 1: as electricity runs through a circuit, one of the by
Speaker 1: products is heat. We haven't figured out a way to
Speaker 1: get around that yet. It's just one of those one
Speaker 1: of those realities that it's uh um. Basically it's inefficient
Speaker 1: enough where some of the energy is being converted to
Speaker 1: heat energy instead of you know, what it is intended for.
Speaker 1: So so now we've got down to the the idea
Speaker 1: of these two different image sensors capturing uh information in
Speaker 1: different ways um, and the fact that over time both
Speaker 1: both types of sensors have developed to the point where
Speaker 1: the differences between the two, apart from the fundamental difference
Speaker 1: of how they collect information, have started to to diminish. Right,
Speaker 1: so that you can find some professional cameras out there
Speaker 1: now that you CMOS image sensors, whereas you know, a
Speaker 1: few years ago that was really unheard of, and you
Speaker 1: can also find some consumer cameras, especially in the cam
Speaker 1: Quorter realm, that are using cc D image sensors, which
Speaker 1: again for a while you just didn't hear about because
Speaker 1: c c D cameras were so expensive. It was pretty
Speaker 1: much reserved for professionals, you know, just consumers just didn't
Speaker 1: necessarily have the money to drop on something like that
Speaker 1: unless they were you know, one per centers. So yeah,
Speaker 1: it's it's it's it's still a developing thing and we're
Speaker 1: still seeing that kind of level out. But that and
Speaker 1: the two technologies do still exist. They coexist, so it's
Speaker 1: not like one has been abandoned on top of in
Speaker 1: favor of the other, although that tends to their bit,
Speaker 1: there's usually someone predicting that every few years. Well sure sure,
Speaker 1: um yeah. A lot of the research that I did
Speaker 1: for the podcast was from Teleedian Do also which makes
Speaker 1: which makes both types of sensors, and they had some
Speaker 1: really interesting, uh comparative white papers and other information if
Speaker 1: you're interested in getting into the depths of it. It
Speaker 1: got some of it got fairly complicated, um, but basically
Speaker 1: they had one paper that said that they're the image
Speaker 1: sensors can be measured on basically eight different characteristics UM.
Speaker 1: And these were responsivity, you know, basically how responsive that
Speaker 1: the sensor is. Uh, it's dynamic range, uniformity, shuttering, UM, speed, windowing,
Speaker 1: and anti blooming UM. And you know, again this is
Speaker 1: kind of you know complex, but the the UH, it's
Speaker 1: kind of funny because the way that the image sensor
Speaker 1: cap information UM, you know, depending on the type that
Speaker 1: you're talking about, they're not really uh, it's really application specific.
Speaker 1: UM some of them. Some of them really don't have
Speaker 1: that much difference over the others. Like, for example, UM,
Speaker 1: CMOS chips are known to be a little bit more responsive. UM.
Speaker 1: But c c D s are have an advantage in
Speaker 1: dynamic range. But basically they didn't say, you know, the
Speaker 1: this one chip is better than the others. They said
Speaker 1: it has more to do with the manufacturing capability and
Speaker 1: whether the chip has done right and is used in
Speaker 1: their correct setting than it does UM, you know, for
Speaker 1: a particular type of technology. Right. And you were mentioned
Speaker 1: mentioning the fact that there are different shutters. In general,
Speaker 1: a CMOS image sensor uses a rolling shutter. UH. There's
Speaker 1: nothing saying that it couldn't use the same sort of
Speaker 1: shutter that sc D image sensor does, which is a
Speaker 1: global shutter. There's nothing saying that it couldn't. It's just
Speaker 1: that all the camcorders I looked at specifically because this
Speaker 1: really plays more into video than than uh, still photography.
Speaker 1: Although there's some crossover between the two. Um it said
Speaker 1: that you could have a CMOS with a global shutter.
Speaker 1: It's just that you don't find those so once they're
Speaker 1: between the global shutter and a rolling shutter, well, a
Speaker 1: rolling shutter to me, when I the first I read
Speaker 1: about this, the first thing I thought about was, UM
Speaker 1: a copier or a scanner where the image sensor you
Speaker 1: put the document on the on the screen, you close
Speaker 1: the UM the top the lid, and you tell it
Speaker 1: to go ahead and make a copy or make a
Speaker 1: scan of it, and the image sensor travels down the
Speaker 1: length of the document from the top to the bottom
Speaker 1: or you know however exactly and and it is going
Speaker 1: you know, from it's starting at a specific point and
Speaker 1: capturing the entire document as it travels the length of it.
Speaker 1: And uh, you know, because it's going essentially line by
Speaker 1: line if you think about that. In pixel tern is
Speaker 1: taking a row of pixels and then another row of
Speaker 1: pixels and then you know, as it goes down right. Yeah,
Speaker 1: I was thinking of it sort of the way television works. Yes,
Speaker 1: where it'll it'll you have a line by line from
Speaker 1: the top to the bottom. Um will ignore the interpalation part,
Speaker 1: otherwise we have to get really complicated. But anyway, the
Speaker 1: image is painted essentially on your screen from the top
Speaker 1: to the bottom at a rate that's so fast that
Speaker 1: your eye does not detect that. It looks like it's
Speaker 1: all simultaneously projected to you, but it's actually done line
Speaker 1: by line from the top of the screen to the
Speaker 1: bottom of the screen. Same thing with a rolling shutter.
Speaker 1: So when you take a photo or you're using a camcorder.
Speaker 1: Let's stick with camcorders. So if you're using a camcorder
Speaker 1: that has a rolling shutter type of image sensors, we're
Speaker 1: talking cmos. Uh, the the images being recorded from the
Speaker 1: top to the bottom over and over and over again. Okay,
Speaker 1: so uh with a cc D camera, it's a global shutter,
Speaker 1: which means that it's capturing all that data all at once. Yes,
Speaker 1: sort of like film would. Yeah, so it's not it's
Speaker 1: not um, you know, it's not something that's gonna be scrolling.
Speaker 1: It's all one image. So this means that the two
Speaker 1: different types of image sensors are also prone to two
Speaker 1: different kinds of flaws that can happen when you're using them. Well,
Speaker 1: of course, I mean that's that's like any other types
Speaker 1: of technology. Not everything is suited for every use, right,
Speaker 1: So let's say that let's i'll talk about the different
Speaker 1: flaws that you can find. C c D essentially has
Speaker 1: one type of flaw that you can encounter, which is
Speaker 1: called the smear effect. So smearing is let's say that
Speaker 1: you've got a a you're taking an image of something
Speaker 1: that has a bright light in it. Um Smearing is
Speaker 1: this effect where you sort of see the light. You'll
Speaker 1: see like a projection of light above and below it,
Speaker 1: or you know it's that's that's why it's called smears.
Speaker 1: It's been extended beyond just a source of light itself.
Speaker 1: It's kind of like a halo effect, though usually it's
Speaker 1: more of at least in the samples I've looked at,
Speaker 1: it's more of a vertical thing where it looks like
Speaker 1: it's almost like a ray of light that goes straight
Speaker 1: up and down the the the screen from the source.
Speaker 1: So that's one of the things that c c D
Speaker 1: image sensors can fall victim to, but not CMOS. And
Speaker 1: it's all because that global shutter exposes that image, the
Speaker 1: whole image simultaneously, and it's all gathering that light. And
Speaker 1: once the predetermined shutter speed for that global shutter has elapsed,
Speaker 1: it stops gathering light, turns that that entire exposure into
Speaker 1: an electronic image, and then starts again. And the rolling
Speaker 1: shutter just doesn't have that aim effects, so the smear
Speaker 1: does not happen with that, and it's you know, it's
Speaker 1: very noticeable. If you see the the effects of this,
Speaker 1: you'd think, oh, well, that's unfortunate that there's this weird
Speaker 1: shaft of light right there in the middle of the frame. Well,
Speaker 1: that's that's it for the c c D. Okay, that's
Speaker 1: the that's the one flaw that's c c D image
Speaker 1: sensors can can fall victim to. But they're the one
Speaker 1: known thing that people complain the one thing that people
Speaker 1: complain about. There are three three different ones for CMOS.
Speaker 1: The first is called skew Okay, So you've got this
Speaker 1: rolling shutter and it's going from top to bottom as
Speaker 1: it's recording images. Now, the shutter is going off u
Speaker 1: multiple times per second. But let's say that you are
Speaker 1: panning the camera very very quickly from one side to
Speaker 1: another there, so you're changing the view. Well, you're having
Speaker 1: a rolling shutter and you're panting the camera. This can
Speaker 1: cause the idea of skew. So let's say that you
Speaker 1: have something that's, uh, that's significant, a big thing that's
Speaker 1: in the frame of the photo, maybe maybe like a tower.
Speaker 1: All right, so you've got a tower in the frame
Speaker 1: of your image, and you quickly pan from left to right. Well,
Speaker 1: as you're panning, that shutter is rolling, and if your
Speaker 1: pan is fast enough, then the shutter is actually going
Speaker 1: to start building an image where the pixels at the
Speaker 1: top of the image are further on one side than
Speaker 1: the pixels that are at the bottom of that image,
Speaker 1: because it's not capturing all that data simultaneously. The outcome
Speaker 1: of that is that you get a skewed image when
Speaker 1: the output image itself is skewed. So that tower, which
Speaker 1: might be perfectly straight when you look at it, when
Speaker 1: you start looking back at the video and you're playing
Speaker 1: it back really slowly, it's only it looks like it's
Speaker 1: leaning or it's diagonal. It's like that. You know, it's
Speaker 1: suddenly not it's not true anymore. Now I understand what's
Speaker 1: wrong with all those vacation pictures I took in pizza. Yeah, exactly,
Speaker 1: that's the that's it. You know, it's no, it's not
Speaker 1: it at all. But anyway, that's that effect is because
Speaker 1: of that rolling shutter, you know. And again, a global
Speaker 1: shutter would not have that problem because it's taking all
Speaker 1: that image, you know, it's taking all the information all
Speaker 1: at once. The rolling shutter is taking it bit by
Speaker 1: you know, line by line. And again it's only if
Speaker 1: you're panning very quickly, because it's this is going so
Speaker 1: many times per second that if you're doing a nice
Speaker 1: slow pan, it's it's not noticeable. Also, you're more likely
Speaker 1: to prevent the kind of nausea that's associated with the
Speaker 1: the quick panning of Yeah, we'll get to there's a
Speaker 1: human advantage to that too. Next is the wobble. Yes,
Speaker 1: so you don't have this problem. No, This is wobble
Speaker 1: is when you get sort of a weird, stretchy or
Speaker 1: rubbery look to stuff that's going on in the video,
Speaker 1: and it tends to happen with handheld footage, right because
Speaker 1: you're when you're holding the camera, you don't have that
Speaker 1: steady base that you would if you're using a tripod.
Speaker 1: So let's say like a found footage film. The sure
Speaker 1: becoming more and more popular these days, so something like
Speaker 1: all Onlines of Blair Witch or clover Field or or
Speaker 1: one of those movies or or or vhs made by
Speaker 1: friends of mine. Check it out. It just it just
Speaker 1: premiered over at Sundance. Um, that's a shout out to
Speaker 1: my buddies anyway, So same sort of thing. It's it's
Speaker 1: because of that rolling shutter, the information is being captured
Speaker 1: line by line. If your camera is not steady then
Speaker 1: and if it's moving around quite a bit and at
Speaker 1: a fairly fast pace, then it's the The images are
Speaker 1: not going to be uh, they're not gonna be clear.
Speaker 1: They're gonna end up having this wobbly, stretchy look. So
Speaker 1: let's say you're panning uh down, so you've got you
Speaker 1: you maybe you've got your looking at the top of
Speaker 1: that tower, and you start panning down very very quickly
Speaker 1: to say, simulate a fall. So we're panting down very
Speaker 1: very quickly. That rolling shutter is going up from the
Speaker 1: top to the bottom very quickly. As you are going down,
Speaker 1: the shutter is going to UH. If you're matching the
Speaker 1: shutter speed or getting close to the shutter speed, it's
Speaker 1: going to make that building stretch out, it's gonna look
Speaker 1: very odd. Um. And so that's another one of those issues.
Speaker 1: And again the global shutter doesn't have that problem because
Speaker 1: it's not it's not capturing information the same way. UH.
Speaker 1: And then finally there's partial exposure. Partial exposure happens when
Speaker 1: light is hitting the shutter or the the image sensor
Speaker 1: at a very particular moment, and and the light is
Speaker 1: hitting it just fast enough so that when the rolling
Speaker 1: shutter starts, the light's not there. But before the rolling
Speaker 1: shutter has finished, it's it's a journey across the image sensor.
Speaker 1: The light has coming gone, which means that part of
Speaker 1: your image is going to be much brighter than the
Speaker 1: rest of your image. So if you think about your
Speaker 1: image as UH, let's say you're taking a picture of,
Speaker 1: say a poster, all right, you gotta you're looking at
Speaker 1: a poster and there's a flash that goes off as
Speaker 1: you are taking your image, and the flash is moving
Speaker 1: at a speed. It's a very quick flash moving. It's
Speaker 1: moving at speed that's faster than the rolling shutter is.
Speaker 1: When you actually look at that picture, when you're looking
Speaker 1: at the poster in the back, it's gonna look like
Speaker 1: there's this one band of the poster that's much more
Speaker 1: brightly lit than the rest of the poster, and that's
Speaker 1: going to be the moment when that flash hit the
Speaker 1: image sensor as the rolling shutter was going down the sensor.
Speaker 1: So this is another issue you have to work with
Speaker 1: your lighting in order to avoid it. And uh, you
Speaker 1: know it can if you're using a flash that's a
Speaker 1: longer based flash, you don't have to worry as much.
Speaker 1: This is why partially why anyway part of it because
Speaker 1: it's most of the the smartphone flashes or l E
Speaker 1: D s, But it's also part of why if you
Speaker 1: ever take a photo with a smartphone that uses an
Speaker 1: LED flash, it tends to last a while. It's because
Speaker 1: if it didn't, then your all your images would come
Speaker 1: out with this weird banding issue. And you don't want
Speaker 1: bands in your in your pictures unless you're at a concert.
Speaker 1: I'll be taking some tonight, awesome, I'm gonna go see
Speaker 1: they might be giants and that's a shoutout today, might
Speaker 1: be giant. Everyone's getting shoutouts today. Apparently it's free plug
Speaker 1: day on tech stuff. Well, you know a lot of
Speaker 1: stuff on tech stuff requires a plug. Yes, it's true.
Speaker 1: Not everything is better reoperated. So yeah, the the c
Speaker 1: c D is only prone to the smear issue, whereas
Speaker 1: CMOS has those other three now have a decent camera
Speaker 1: you shouldn't have, you know, and O are taking precautions.
Speaker 1: You just have to worry about it exactly. Yeah, if
Speaker 1: you if you know what you're doing, you can get
Speaker 1: around these problems. It's just that these are the ones
Speaker 1: that are the cameras are prone to based upon the
Speaker 1: technology they use. So it's not that every single image
Speaker 1: you're gonna take, or even even like a significant percentage
Speaker 1: of the images you'll take will have problems associated with
Speaker 1: these issues that I've talked about, but some of them might.
Speaker 1: And the reason why they they have those is because
Speaker 1: of the technology itself. And again, you know, you just
Speaker 1: little basic tricks that you can do, you know, just
Speaker 1: for example, using a tripod whenever you can helps a lot,
Speaker 1: it'll it'll really remove a lot of this also, you know,
Speaker 1: most of most people aren't running around and jerking the
Speaker 1: camera left and right so fast that these are really
Speaker 1: coming into play. Uh And if you're using Instagram, really,
Speaker 1: you've made your image look so crappy already you don't
Speaker 1: need to worry about these effects. Nice, that's that's just
Speaker 1: a joke. Mostly my wife uses Instagram a lot. What
Speaker 1: a lovely old tiny photo of the Space Shuttle. I'm
Speaker 1: so glad anyway. Uh so, yeah, I mean, so which
Speaker 1: which is better? Really kind of it really does depend
Speaker 1: on what kind of photography you're going to be doing. Um,
Speaker 1: you know, probably the biggest difference is whether you're doing
Speaker 1: still photography or or video. And most of the time
Speaker 1: when you're shopping for cameras, the type of sensor that's
Speaker 1: in it is not necessarily the easiest information for you
Speaker 1: to find out, although it does pay to to look
Speaker 1: into that if you can, and and actually do some
Speaker 1: research on the sensor itself, because like we said, the
Speaker 1: sensor and the lens of the camera is going to
Speaker 1: have a lot more to do with the quality of
Speaker 1: the images that you get using that camera then how
Speaker 1: many megapixels it has. So even if you go out
Speaker 1: there and you buy a twelve megapixel camera and your
Speaker 1: buddy has an eight megapixel camera, your buddy's images maybe
Speaker 1: may look sharper and more vibrant than yours. Again, not
Speaker 1: to do with the megapixels. It's more about the lens
Speaker 1: and the sensory And of course, if you're you're planning
Speaker 1: on dropping a lot of coin on a new camera,
Speaker 1: probably would be a good idea if you read some
Speaker 1: reviews from professionals to give you an idea of what
Speaker 1: to expect and to see if if other people are
Speaker 1: using it the same way, you will be um to
Speaker 1: get to really get an idea of how you know
Speaker 1: whether it's going to suit your needs, and that's the
Speaker 1: most important thing. Very good, yes, good advice from Mr Pallette.
Speaker 1: I think we should probably wrap this up because our
Speaker 1: our guest producer, Liz is out there and she's a
Speaker 1: photographer and she's probably about ready to explode with all
Speaker 1: the information we've given and say, well, actually she hasn't
Speaker 1: screamed it us yet, No I know, but I've seen
Speaker 1: like a couple of things fly at us through the curtains,
Speaker 1: so she's just not Luckily, she throws like a girl,
Speaker 1: so I'm just kidding. I'm just kidding. Actually she could
Speaker 1: probably be me. I'm hearing noises now. I take that back.
Speaker 1: Girls throw really hard, which is harder than I can anyway,
Speaker 1: So let's wrap this up while I shoved my foot
Speaker 1: further into my mouth. If you guys have any comments
Speaker 1: or questions or suggestions for us, you can let us
Speaker 1: know on Facebook or Twitter. Are handled. There is tech
Speaker 1: Stuff h s W or send us an email. Our
Speaker 1: andress is tech Stuff at Discovery dot com and Chris
Speaker 1: and I will talk to you again really soon. Be
Speaker 1: sure to check out our new video podcast, Stuff from
Speaker 1: the Future. Join house Stuff Work staff as we explore
Speaker 1: the most promising and perplexing possibilities of tomorrow. The House
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Speaker 1: twelve camera. It's ready, are you