Lessons

Lesson Info

Camera Mechanics

Let's talk about the things that we have to control now all right we're going to compare these cameras in a little bit after I show a little bit more we'll compare what they do but um exposure exposure I'm gonna slip forward once line then come back exposure our eyes and the world the world has a very wide range of dark to light and our risers are magnificent at being able to handle a very high dynamic range all right I can look at right now if I look at what I see here this monitors on the ground is very bright you guys were kind of right but those women in the corner over there are very dark but I have no problem handling all of it at once same thing if I'm sitting if I'm sitting somewhere and I'm seeing someone and they're sitting near a window I can see the brightness of outside and I can still see details in their face well the video camera is not that doesn't have that big a wide range so we have to really be very careful how we do our exposure when this is the same scene over ex...

posed underexposed and exposed well you can see that when it's overexposed you're losing the details the shadows that you know should be there aren't there and you're losing details in here there's a you don't even know what those waves are they're they're just totally broken up here when you're under exposed you don't see what you're supposed to see here so it's really a lot of it of the first thing that we really have to work on is how do we expose our images so that they looked like what we want and that is not just a technical thing of you know the cameras have automatic exposure settings on it but that automatic exposure setting basically saying I don't trust you I'm smarter than you I know what you want not you know what you want an automatic exposure for instance let's say I'm doing a scene where someone is in a shadow the automatic exposure would expose that right or let's say I'm doing a scene very typical scene let's say there's ah there's a person on stage and there's a spotlight on them usually when you see that if you want to see that properly exposed that spotlight should be slightly over exposed on them it shouldn't just look normal if they're in the sun they're going to be that's the sunlight that hits them is going to be slightly over exposed to make it look real if you make that sunlight be normal exposure it little look dark to you so there's an interpretation that goes in there um the way that we control exposure is through the iris all right there's there's these air kind of interchangeable these are interchangeable words aperture iris f stops um the aperture just means how wide is the lens open everybody's seen pictures of lenses that looked like this right where you see that the way that the lens actually works how you control the amount of light that hits the lens it's very hard to show on these lenses because these air totally elektronik lenses they're not mechanical when I changed the f stop I'm no longer changing the aperture opening on the lens itself I'm changing it on the camera so I'd have to I'd have to um can I do that but you understand you will see in this picture of how these these these irises open they're like the iris in your eye it opens and closes the smaller the opening the less light that comes in the larger the opening the more light that comes in okay um I don't know if you've noticed but these numbers are very probably even if you've never thought about cameras before in your life you've probably heard the number five point six you've probably heard the number two point eight at some point in your life if you've done any sort of studying of fillmore cameras you'll know them what but notice what happens the big number equals less light the small number equals more like okay why is that? Because actually these numbers these f stop numbers that we assign and we usually these air the numbers we usually go with one point four two two point eight for five point six eight eleven sixteen each of these numbers when we say for what we're saying is it's actually the reciprocal of that it means that if we've got a lens that looks like this and there's an iris in the at the back of the lens that opens it up and let's say the iris is open that much it means that this opening the diameter of this opening is one quarter of the focal length of the film of the lens that's what that means so that means that if I have all these different lenses no matter how long the lenses no matter what the lenses if I said it to f four it's going to put the same amount of light in the camera no matter what the lenses all right? So that if I decide well, this is the right this is the right this really needs to be an f four and I change the lens to a wide angle lens if I said it to f or the explosion will be the same. Okay, so where is an f sixteen over here means that that this opening is actually one sixteenth it's much smaller so that's why the big number means less like okay, just just for that for future I don't know if you notice but everyone every other one of these is double in terms of the number it's it makes it easier to remember them uh sorry this is not good four times two times eight and then some sixteen you see how they're they're double each the difference between each one of these stops is half are twice as much light if we were taking a longer of course we'd really work on this a little more but because of what we are so basically f two let's in two times as much light as two point eight it let's say in four times as much light as four it lets in eight times as much light as five six eleven let's in half a cz much light is eight let's say a quarter as much light as five six let's say an eighth as much light as for lets in a sixteenth as much light is thirty two so as you as you see this, can we pop this up real quick? The x three please let's just look at let's just look at this and I'm I'm gonna ask him to turn this menu back on so you can see the numbers down there okay? Now uh didn't come up something on one second video hit the wrong one sorry okay, all right, so watch in the bottom part of the screen here this is the f number here, okay I want to just leave this here all right, what would you say looking at this image right now would you say it's properly exposed over exposed underexposed yeah let's put a person in there maybe that'll help I don't know. Is that properly exposed or not? Little over I think a little over I think that there's you know a little over so anyway, but that's wide open okay, that one point nine that f one point nine is the widest this guy camera will go now I'm going to close it down to a two point eight okay that's that's that's a little less than half assed much light coming through I'm going to close it to a floor that's going to be half as much as the two, eh? Okay, I'm gonna close it to a five six so each time I'm taking away half his much light that should really be in a okay, those air in between. All right. Okay, so this is just to see how that's working I think when when I really look at it. I don't know I'm on a side angle so it might look different to me, but basically to me, this looks like a better exposure I don't know, maybe maybe so four point eight is between five and five six maybe the four, okay, so I think that's enough for us to talk about this for right now we'll get we'll get into it a little bit more, uh, some of these cameras and this is it's one thing to talk about camera operation in general, a lot of every camera is different, so I'm not going. We're not going to really deal with all these because what I learned on this camera when you might never use it but would just talk about the basics there there are something called zebras zebras are an electron ic you I can see them in this viewfinder, but I can't show them they don't they never go onto the film you don't ever want to see them on the film, we talked about the neutral density filter before remember how I flicked that in and it made everything darker because if we go outside, these cameras are set up to be sensitive enough to be used inside, but when you go outside where it's really really right out there, you um you there would be totally overexposed they'd be way more over exposed in this so that's what these neutral density filters air in this this one is two stops in other words, it lets in a quarter of the light that this this camera has three of them on this one only has to but four stops is a sixteenth of the light um there's another thing that I want to show you which is gain or so all right that's something that's on these cameras and it's away again it controlling your image is, um what happens is I said these cameras are sensitive to a certain level they are designed so that you can use them indoors where where there's not a lot of light but you can adjust the sensitivity of the camera by either changing the esso which depending on when you started making film used to be called esa only use that once just so you know it's the same thing occasional hear people say essay if they're older and you say what what's he talking about um but basically what gain does and what? By changing the a on these cameras, you're adding a little bit of elektronik noise that makes the camera more sensitive? It allows it to seymour in the shadows, but you lose things. Okay, this is a picture that's been blown up, but this is zero this is no game uh when I when I call these once I gain when I say gain an esso gain is the video term that you'll see on a video camera like this I s o is a term that you'll see on lars because they're coming from a tradition of film so that's it it's exactly the same thing. It's a way of increasing the sensitivity so what's happening is this is with no gain and this is with twelve d b of gain. So what? What what happens here? Well, you can see that you seem much more into the shadows, but also there's a lot more noise and the color is going away okay, on this camera, the game the game is on is on these little switches that I showed there before I'm gonna leave this game. I'm gonna leave these on for you guys now, but this is where we watched the game see where it says doobie right now the game is off. I mean me meaning there's no extra game added to it. Watch what happens when I flick it toe two, this is six tv game, all right? And then this is twelve d begin. Okay, now it's hard to first of all, you see that it does add a lot more sensitivity. All of a sudden it gets a lot brighter, but I'm going in now I'm going to adjust. I'm going to just when when I go to twelve d b gain, I'm going to bring it down, I'm going to close the iris closed so that so that it becomes this color again and then you'll see the difference and it becomes this this density that that kayla's face becomes what it is right now if you look at it you do see some noise in there I don't know if you can see it from where you guys are you can't all right I'll encourage you to come up at some point let me just show it but right now you can see kind of little it's almost like little mosquitoes moving around but I'll show you ok so right now I'm going to change it to twelve d b gain which is not a tremendous amount of gain by the way so there's twelve d b and now I'm gonna darken it back to that so now you can see the noise right I mean even from where you're sitting you can see the noise but you can also see that the color is not is nice is it going back to the normal this is a little bright all right here we're gonna go the twelve d b game you can see the noise and I to me I can see that the colors aren't quite as true I see jessica's shirt is getting is got a little less green in it let's see we'll do it one more time do you see the difference it's it's just it's a little bit if I were to put more gain in here what's more gain enough just for a second here's where we set up the game I'll make this high gain into eighteen d b see what happens there okay so now I'm gonna go to eighteen deba gain and now you can see look how much noise there is in adrian shirt and you see how the colors really have disappeared now so I would see that for most that they're they're just not they're just not they're not as rich any more I would say that um eighteen d b gain is pretty unacceptable for most uses right? This is sixty be gain which you can usually get away with that's sixty begin to see that they're on the bottom where it says that okay um let's go back to the show we go back to the to the slides please okay. Yeah dad um I was just wondering why uh for gain they used gps and isn't decibels it's decibels yes it's exactly decibels it's for yeah with video it's the same decibels this but it's you know it's it's just again it's coming from the different tradition there were not that long ago there was there was filled and there was video and people saw the world entirely differently they get they looked at everything entirely differently and now that most films they're being shot on video cameras there has been a move they've they've come together but that's still that d be term is an engineering term just as our eyes were incredibly sensitive to seeing dark and light, you could see you could see the details and someone who shadowed infront of outdoor the same thing where our eyes are tremendously good at seeing color and at imagining color I whatever room color is in this room right now I can look at it and I can know that that's a yellow pad on your and I know that's a white pad when I really look at that when I really look att eric's pad here I know that the actual color on it is not really white, but I kept my eye sees through it well, the video camera doesn't do that very well the video camera is really it doesn't interpret in the same way so um so what happens is you have to tell the camera what color the lightest um can you sweet please switch to this camera and I'm going to just very, um all right let's see how we're going to do this? We'll do it this way what kind of trick? This camera just to show you really quickly what we're doing here um okay, okay, so what I've done is I have told this camera right now this camera should be this camera has three white balance setting his settings on it I don't see any change in here maybe sing a little while okay the one that the one that's a preset I don't know if you can see this when I switch it it says p w p white is for white balance preset that is set for the room that this that has been set up for the lights that are in this room okay so that when I'm on when I'm on your face here that you look about right okay at least through this monitor and through the through the system when I have when I what I just did is I tricked it into seeing other colors so that you can see very very dramatically this one I've changed it to thirty two hundred so what's going to happen here is it's going to take a second to really get there but you see how blue you've become because what I've done is I have changed it so that it looks it at at what we call indoor like tungsten light so that when it sees these bluer lights everything is very blue and then I've taken this one and I've turned it to a much bluer look so that when I switched to this b is going to change and and she's going to turn into another color yet she's going to turn much warmer it takes a while for it what it does it doesn't switch instantly in case you're switching from indoor and outdoor it's keeping you from looking like you've made a mistake you can see that now that it's really warmed up and it's really in there you can see how much warmer it isthe. Okay, so so this is something this is both. This is something that we want to maintain both in our we want to maintain it both in our when we want something to look real and if we want to change things a little bit let's say we want to put someone against a character in our moving. Maybe we will make them a little bit bluer, right? We can do it with lighting or we can do it in here. Or maybe we want someone to really feel more comfortable with somebody else where they feel warmer to someone. We might make them a little bit more orangy. We want todo a cent. You know, you want to do a difference between someone's home life and their work life. Let's say the guy is ah let's. See is a killer for his work. Well, maybe his home life when you see him at home with the family, use warmer light. And when you when you see him at work maybe it's a cold, hard blue light you know, the cold light of the killer.