 This is 18% gray, 18% gray. And this is about the way that your camera averages out all the light that it sees to make an image. So if you take your eye and you were to make everything that your eye sees around you, black and white, and then you were to take all the tones that you would see. So instead of these colors, you would see just tones of gray. If you take them all and throw them into a sort of a washing machine or into a blender or something like that and let them all mix together, they would kind of wash out to about an 18% gray on a sunny day. So that's an important thing. If you're kind of outside and it's a sunny average, well-lit day, or you're maybe inside on a well-lit day, it's going to average out to about 18% gray for most scenes. Now, not everywhere and not all over the place. You'll see why that isn't true in a second. But that's just an important thing to know. That's why what your camera is trying to accomplish. And it's the reason that a lot of your images might come out wrong or come out underexposed or overexposed when you're doing photography. How about we then talk a little bit about how this all happens and how the camera evaluates this 18% gray? We're going to make a couple little metering systems here. So imagine we're looking through some cameras. So we've got one camera here. We're going to make four cameras. One camera here, and they're getting progressively bigger. They're also getting progressively more complicated as we go to the right here in a second. You'll see what I mean by that. All right. So here we've got our four frames. And we're going to start out with our average. This is kind of not one that you see very often. But your average meter is just going to take everything that it sees in the entire frame. So you're looking through and you're seeing maybe a mountain or something like that with a little creek or something. And it's going to just take all the light that it sees and look at it just the way that we did in that first slide, where it's going to try to make everything even all of the colors out to gray. And that's called an average meter. Now that's one way to do it. Another way to do it is to have a spot meter. So spot meter is just a little tiny spot, often in the center. And a spot meter is going to just measure the light falling on that little point in the image. So you have to know where your spot is. Often it's going to be marked on your camera. Modern cameras, you can move the spot all over the place. Older cameras, it's usually just right in the middle. And that spot meter is going to try to find 18% gray in that little point in the camera. And then what you'll do is you'll point that spot in your viewfinder towards something that is about 18% gray. So if you're somewhere where you have maybe a sidewalk, that's about the perfect gray. You can point it towards the sidewalk. Check your readings. Check what your shutter speed and your ISO and how everything is working out. Set your shutter speed, and then turn back to your scene and take your photograph. So that's how spot meters sort of traditionally work. These days you can use them a lot more accurately and specifically. Your next kind of metering system is called center weighted. And so you'll have sort of like a big spot here. And then sometimes it'll even have like a slightly bigger one around the outside of that. And this is called, like I said, center weighted. There's a little dash in between there. And center weighted basically means that there's going to be kind of a spot in the middle. So it's going to be a little bit bigger often. But you'll have sort of a spot in the middle. And then a bigger spot that's also pretty light sensitive around the outside. And then maybe a tiny bit out here. So it might take like 50% of its information from here. It might take maybe 40% from here. And it might take 10% of its information from here, for example. So things like that will happen. But center weighted work differently for different cameras, different models. Every center weighted meter works a little differently. I have to say center weighted is my favorite way to meter things because I just kind of feel like I understand that waiting, that metering system a little better is also the one I've always used since I was first doing photography. But the other ones are great too. I also use a lot of spot photography. And I never use my averaging meter. So just even though it can be really great, I've never really used it. Now the last one is sort of, well, there's lots of different names for it out there. I'm just going to call it the multi-zone. Because that's the non-corporate way of saying it. The thing is that every company has its own way of creating multiple metering systems that these sort of advanced metering systems that are coming out today that are something, they're often a combination of a center weighted and an average. So you'll have a center in the middle that's maybe accounts for 60%. And then you'll have these different zones. Over here, you'll have a zone. And over here, you'll have a zone. And you'll have another one here. And you'll have another one here. And I would recommend for beginners, this is also a really great metering system. Most of the new ones are really good. They do a great job. A lot of them are even comparing your image, the one that you're looking through the viewfinder at, thousands of images that are on a little computer chip on the camera. So you'll actually get often a very good metering from a multi-zone. And sometimes you'll cure it called an evaluative or a segment, maybe a honeycomb or a matrix meter. So you'll hear lots of different names for this. And just remember that they're all just multi-zone, sort of fancy, modern age light meters. They're the kind that have really come out in the last 10 to 20 years. All of these other ones are older and sort of more tried and true. In my opinion, I like them. But I also use my multi-zone meter for complicated metering all the time. Now, how do you actually read this? This is actually probably the more complicated part of it or the more practical part of it. It's really important to understand how your light meter is reading the scene. And you want to know what your light meter is seeing. But you also want to know how to read it. Now, on the sides of older cameras, a lot of times you'd have just a little plus and a minus. And then you would have a little kind of like a needle that would stick sort of into the side of your picture. Or maybe you'd have like a little LED or something like that. And in the middle, there was a spot where it was perfect. And then when it went too far towards the plus side, you were overexposing. And too far down towards the negative side, it was underexposing. You also had the phenomenon for a very long time of numbers just being written on the side. So you'd have like 500, 250, 125. And then you'd have another, again, same thing, needle coming in saying, oh, 250 is your right shutter speed for this f-stop. And you would set your f-stop manually, and then it would tell you what shutter speed was correct. This was really common with aperture and shutter priority cameras for a long time. The modern version of this is actually a lot nicer to use. I have to say I have a couple cameras that have this. And you'll have one that has kind of a zero in the middle, kind of a line. And then there will be kind of a line like this. And it looks different on every camera that's out there. But then you also are going to have a 1, a 2, and maybe even a third hash here. So 1, 2, and maybe 3. And then 1, 2, and maybe 3. Sorry, my graph looks a little bit inaccurate here. Between each of those steps, you're probably going to have two steps in between each one as well. And those are what are called third steps. Now if you guys remember how we were talking about shutter speeds and f-stops and ISO speeds, this is one stop. So that's one stop. This is also one stop going this way. And the same going here, and the same going here. So you could just call it one stop, 1, 2, and 3. Stop, 1, 2, and 3. And maybe this is going in the underexposed direction. And this is going in the over-exposed direction. So the plus will be overexposed. The minus will be underexposed, just like in these old cameras back in the day. The great thing about this is that you're going to have a little blue needle again. But this time it's probably going to be like a light or some sort of little notch on your screen or something like that. And this will slide this way and that way according to how your camera is doing on its exposure at that moment. So if your little blue line is over here, that means you're going to be overexposing by two stops. So that means that your photograph is going to be way too light. So I'm going to write too light over here. And this will be too dark. And so, like I said, the same thing applies if you're over here, your two stops underexposed, which means you would need to change your f-stop by two full stops to get to your correct exposure. Now, sometimes you want to underexpose. Sometimes you're looking at a scene and say your spot meter is on a spot that is maybe one stop darker than 18% gray. So you look at it and you're like, it's not quite 18% gray. That's maybe like 30% gray. And maybe it's about one stop, or maybe almost two stops too dark. And so you're going to know that that's not 18% gray and expose for that correctly. But generally, you're just going to, most of you are going to be using multi-zone metering. And you're going to then just let it do its thing. And maybe once in a while, jump in and sort of do a little bit of adjusting. You're looking at a dark scene. If you're looking at a black photograph, and it's telling you that it wants something over here, then you're going to know a little bit more over here, maybe, or the other way, actually. It'd probably be more like that. So you just want to always keep in mind how this system is working. First of all, to know what your meter is reading and what it's seeing, because that's really important. If you have a really bright light source here that you want to expose for, but your spot meter is there, it's not going to work right. So you're going to overexpose maybe for your light source, because you're looking at a darker spot in the photograph or the other way around. Maybe you want to expose for something that's over here, but there's a big, bright light right behind your spot meter, the same with your center-weighted meter. And you just want to keep all of that in mind for when you're looking at all these charts. Light meters are really made to work with these kinds of scenes. This is exactly what I was explaining in the beginning. If you were to take this photograph, make it black and white, and throw it in a blender, you'd probably come out with about 18% gray. That's probably almost the average of all of this. So these are the kind of scenes that light meters really excel at. Scenes like this, however, are not very good. Because the thing is, if you were to average all of this light out, if you were to average out the area I was using a center-weighted meter that was right here. Actually, it was more like a spot meter, really. And the thing is, is that the light inside of that circle there is not 18% gray. That is probably not even close. It's probably something like, maybe it's like 7% or something like that. I mean, it's very light. It might even be like 4%. Who knows. So generally, when you are shooting in snow, you have to overexpose on purpose because you know that you're shooting something that is white. It's not gray. It's white, so you need to let the shutter be open a little longer, let a little bit more light into your camera. And so you're going to overexpose by one and a half, sometimes two stops. Somewhere in there, sometimes a little bit less. But generally, one and a half to two stops is kind of a good start, depending on the conditions. Here's a situation where the camera probably wanted me to overexpose. It was actually kind of doing the opposite of what was happening in the other image, because it would see all of this black, and my camera would look at all of this and be like, oh, I want to make that light. I want to make it look like this here. The camera's trying to make everything look sort of like this, and this here, and this here, and all this stuff. So it's trying to match this black to make it light. And that's not what I wanted. I put my spot meter right here on my friend Julia's cheek and said, OK, that's about 18% gray right there, which it is. It's skin color is a little bit off, but about 18% gray on Caucasians. And you can see here that the photograph ended up coming out about correctly. But if you were to just look at this whole scene and do an average metering, you would have to underexpose the image according to the meter reading. Here is another example of a really hard scene to meter. What's so hard about this is that it is backlit. Backlighting is really hard to photograph, especially because you get really strong light sources like this, and they will really mess with your situation. Here, too, you can see the light shining off of this guitar. It kept reflecting into my lens, and it kept messing with my light meter. I watched my light meter go, brrr, and jump to the right or left whenever the guitar was moving. How do you meter a situation like this? Well, you often have to, unfortunately, guess a little bit. I often just spot meter off of whatever I can find, and I spot meter off of Sam's shirt here. Because his pullover, his coat here, was too dark. It's about negative 2, so I could maybe do it there. I could maybe, if I know about where it's at, I can find something that's a reference point that I know is about 18% gray. But another problem with the situation was that the light kept changing. So I just used my spot meter, tried to keep in mind how the exposure was changing, and made it work. So that is a little bit of an introduction to metering. I hope that that gives you a good idea of what things you can do with your meter and how it works. There is a lot to it, and really the only way to learn is to go out and practice. So do that, and then come on back to alversy.org for more lessons.