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Metering Is Not An Exact Science

Lesson 14 from: Understanding Light & Light Modifiers

Mark Wallace

Metering Is Not An Exact Science

Lesson 14 from: Understanding Light & Light Modifiers

Mark Wallace

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Lesson Info

14. Metering Is Not An Exact Science

Mark explores the many ways to meter light and why you’d want to use each. Mark explains TTL (through the lens) metering and common metering modes and how to use a light meter.

Lesson Info

Metering Is Not An Exact Science

let's talk a little bit about metering now what I don't want to do is go through and teach an entire class on how to meet or light. I've already done that and I have another class called studio lighting essentials where we do that. But I do want to touch on different types of metering in the camera and with a light meter, how they're different and just to give you some options of what to choose because there's not one way to meet her light. And in fact as we just discovered there isn't even a perfectly correct meter reading every single time. And so let's just dive into this. I have got a little slide here that sort of breaks down some of the most common ways to meet her. And so metering is not an exact science. We have two major ways to meet her light. We have T. T. L. Metering, that's the metering that's in your camera stands for through the lens metering. And then that metering has different modes And so we have faced priority meeting metering. We've got evaluative metering or with ...

a lot of other brands than Cannon is called Matrix metering. There's spot metering, there's average metering which for studio lighting is absolutely not the best. And then we have these other things that we can do where we can take T tl metering and we can push a button and we can lock it in and then it becomes manual metering, which we're gonna show you how to do. It's really fun and then also we can use a light meter and light meters have different modes so you can do incident metering, which is sort of the default, what you've seen me do all day and then we have reflected metering which uses spot metering plus memory and some sort of zone zone theory to learn how to do that. So anyway, what I wanna do is I sort of want to go through what each of these are to sort of help you understand how they work and which one might be best for you. And then Quinn's gonna come out and we're gonna demonstrate a few of these different ways to meet or light just to sort of help you understand the philosophy of metering a little bit more sort of something I like to do. So what we're gonna do is zip over to Mark's little white board and so uh this is fun. So what we're gonna do, let's first talk about T. T. L. Metering. So that's through the lens metering. So T. T. L. Mentoring me through the lens metering and how that works is light, There's a little sunshine shines and here's the camera, it goes into the camera, the camera has a light meter built in and it figures out the light. So that's why it's called through the lens because it goes through the lens. Um this is great because it looks at the light that is coming from a light bulb or bouncing off. So if the light was up here and here's a wall, the light bounces, still goes through the lens. But the camera is figuring out the light from that right there. Um or if you have something like a television screen. So let's say we have a big screen tv right here from the side and it has light coming out, that light is going to go and it's going to go through the lens, there's our lens and the camera is gonna figure out the correct exposure for this. Where this breaks down is if you have something like a big screen tv here or some really bright lights, city lights, something like that and you have a person or subject in front of those things and you want to know what the correct value is for this person. Well, the light's coming from behind the person and so the camera will a lot of times give you a correct exposure for this and not this. And so it can get things wrong. So what happened is way back in the golden olden days we had in fact Quinn, I don't know, can you give me that black and white and gray card there? So I want to show you sort of what happens with how the camera thinks. And so this is a great thank you. So what we have here is this card and and what T. T. L metering used to do and still does to some extent is it looks at a scene and it expects it to equal this middle grade, this average GRE so if you're looking at uh something like me, I'm monochromatic on purpose and this white and this, if you put this all in a blender and mixed it up and got this middle gray, then that would be the correct exposure. If it was white, I'd be overexposed to be overexposed or etcetera. So what our cameras do is they sort of average all the tonal values from the darkest to the brightest that mixes it up and it expects that mixture at the correct exposure to be middle gray. And so in the beginning we had T. T. L. Averaged so an average meter average reading. So if you had a scene like this and you had a bright sun over here maybe had a person and you had a little dog, whatever. There you go. Well, he looks like he's peeing by a little dog. Um then what the camera would do is look at this entire scene and it would under expose the majority of the scene because it was averaging everything out. And so it would look at all this stuff. This is much darker than the bright sunlight. So it would get stuff like this wrong. And so what happened was camera manufacturers said, you know what, we know this isn't exactly right all the time. There's gotta be a better way to do it. And so what they did is they came up with matrix metering, so Matrix, it's what most camera manufacturers call it, or Canon calls it the evaluative, so I spelled that right. I think evaluative evaluative metering. So what that does, let's say, it takes a look at that same scene. So we have our bright sunlight, we have our person, we have our little dog here. Um so what would happen is the camera would then take this and it would break it up into segments, so they break this scene up into segments and it would look at this and it would say, you know what, these segments up here are much brighter than this and it would look at its little database of imagery and say, you know what, This is probably a scene with the bright sun. So let's not include this little section in our formula for figuring out the correct exposure and it would base the correct exposure on this stuff here because it was a little bit more intelligent and suddenly TT l metering got better and better and better. And so that is really fantastic. Um and that's what most manufacturers use. So if you use a speed light or on camera flash or Oc F flash system and you're using t tl metering most of the time it is using Matrix or evaluative metering because the camera is smart enough to know you have a flash and then you're trying to balance things too correct dynamic range, all that stuff we talked about, so that works pretty good. But the problem still comes in a lot of times if you have uh in the studio, let's say we have a studio, we have Quinn here and we had that really bright light like we did before, we'll even this. Sometimes the camera can get this wrong because this is shining into the lens and it's so bright that the subject is going to be underexposed. If you're trying to do creatively correct exposure stuff, sometimes it just doesn't work correctly. And so what you can do is you can take that scene, um let's say that same scene where it's highly backlit. So we've got happy Quinn here and we have a really bright light right here. What you can do is you can zoom in the camera so it just sees this section and then meter the light and then lock that in. You can say, you know what I know this section is metered correctly, Let's lock it in and then when you zoom back out, the cameras just gonna ignore this, it doesn't care because the exposure has been locked. And so that's a fantastic thing. I'm gonna show you how to do that. And then the last thing about T. T. L. That I want to talk about that is sort of new. Um and so different camera manufacturers have this, some don't, but most new mirror, less cameras have this, I'm shooting with a Canon R five, it absolutely has it and it is called face priority. So face priority metering and this is fantastic. So if you have a scene, here's your person there, what it will do is it's going to look at the entire scene and when it detects a face it's gonna say, okay, this is the thing that I need to make sure is exposed correctly and it's going to give more value, more weight to that than anything else. And that's fantastic because if you have bright lights, sidelights, just things that aren't normally working in matrix or evaluative metering, the camera will most likely get it right. It's really crazy. And the other thing you can do is you can use that with the locking functionality to zoom in on a face lock the exposure zoom out. And even if you have side light, crazy light back light, the camera is probably going to get the metering close to correct, which is just crazy. So I used to be famously opposed to T. T. L. Metering because it got it wrong so often with studio lighting now, uh with if you have faced priority metering, I'm a little more forgiving, I think this is okay, but these for sure average, don't use that on an older camera, you might get away with this. I wouldn't recommend it for me. I don't use t tl metering unless I know the camera, I know it's gonna work really well And I have arguments about this with many of my photography friends all the time. So, David Bergman, a good friend of mine shoots concerts and all kinds of stuff, and he's a T. T. L. Master uh joe McNally, a bunch of people that you probably know of. They use T. T. L. Successfully. But the way that they use it successfully is they've done it over and over and over and over again. They practice it so much. They know how their system works. They understand the different scenes and how to point the camera. And so if you are using T. T. L. Without a light meter, you absolutely can do some really amazing things. But just practice enough until it becomes second nature. And because I'm a light meter guy, I haven't done that and I probably should. Okay, let's talk about light meters. So a light meter, boo boo boo light meter. They have basically two. That's an are they have two different ways of measuring light? So, you have incident. Yeah. And then you have spot or also called reflective. Mhm. And um the way that these work are pretty radically different spot. This reflective metering thing right here is used a lot in landscape photography or fine art photography, because what you do is you look through a little radical, you look through this little scope and it's got a tiny cones, you're only seeing a tiny spot of the scene. So if you have a scene, you've got this scene and maybe it's jagged mountains and it's got a sunset over here and you've got, I don't know, waterfall coming down and you've got birds, whatever. What you can do is you can look through that and say how bright is it only has a different color. So you can see how, what's the luminous value? How bright is it right here because that's really, really dark and how bright is it over here because that's really, really bright and how bright is the sky and how bright is this. And you can start sampling different areas in the image and if you know that you want to make sure that the waterfall is the thing that you are focusing on. You can put it in memory in your light meter and you can put all these things on a little scale. And I will say this goes here and this one is over here and this one's over here and then you can see if all these values are inside your camera's dynamic range and you can plot that out on a scale. It's really cool. And if you find that this is too bright, What you can do is you can use a neutral density filter or something and you can dim that down, you can make that a little bit smaller. This is stuff that most landscape photographers that advanced. This is how they meet her. They do this, there's a function that you can take all these different values and you can average them. And it'll say this one is f this this one is F this. And so if you average all those out, the correct exposure is whatever that is. It's an advanced metering technique. It's really awesome. It takes a while to learn. But that's what this spot, reflective metering mode is on the camera. And that's why you don't see it in the studio very much because it's really designed for metering stuff that's far away like mountain ranges and scenic photography and stuff like that. And so we will not be using that. Um But it's really cool to understand, you need to know a little bit about the zone system, It's more advanced. The thing that we will be using is incident metering. Now the beauty of incident metering is it meters the subject and it meters the light falling on the subject itself. It doesn't meter the light that's reflecting off the subject and that is important. So let's say that we are metering a solid black wall. If we used t tl metering the camera would see this solid black thing and it would think, well it should be great and it would overexpose it, it would get it wrong or if we're metering through the lens something that's solid white. The camera is going to expect that it should be gray and it's going to under expose that and it's going to get it wrong with incident metering, what you're doing is let's say we have solid black wall here and the light is coming in. Yeah, you're gonna meet her the light right here and it's gonna meet her. The light coming into the wall, it doesn't care if this wall is black or white or gray or green. It does not matter. Is metering really the light that's falling on the subject itself, that is brilliant because you don't have to worry about all that averaging and stuff. Um, and worrying about if this is dark red or dark green or like some weird color or if the angle of the light is bouncing in a weird way. Can all throw off through the lens metering with incident metering, you just don't have that problem. It's really wonderful. And so for me when I'm in the studio, incident metering is what I use 99% of the time or face priority TTL metering. And so what I want to do is show you those two things and how it works and we're just gonna have some fun with it. Okay, so let's go over here. I have already set up a demo Wake up my camera really fast and okay, great, so Quinn come on out and just, I don't know if I can come close enough to show you this. So this is a really nice light meter. Can we show Yeah. And so you can see this little thing going through this. This is the spot meter. So you actually look through it like this to figure out what's going on. Um so that's what that is. If you're wondering and I don't think we can show on the bottom of this, There's a scale here where I can plot things out and show different values when I'm using that. You can do that with incident as well, but that is much more advanced metering. Um we'll talk about in other classes, just not this one. So what I'm gonna do is take this, this is called the Loomis Fear. And if you notice the limits fear can go up and down. You see that. So we want to have that limit sphere up because it measures things in 180° this way, 360° this way. And so if I'm measuring light back here, what what this Loomis Fear is doing is it's not only measuring the light coming from the light itself, it's measuring light that's bouncing off the floor. If we had a ceiling here, it's measuring that if I had a white shirt, it would be measuring the reflection. That's one reason I'm not wearing a white shirt, I'm doing this on purpose, so I'm not reflecting light into my meter and causing issues. You should not wear a white shirt if you're a photographer metering in the studio for that very reason. if I had a reflector, it would meet her, the light bouncing off of that is looking at everything that's happening. If I said, you know what, I don't care about all the light reflecting, I just want to meet with the light coming straight out, I know what I'm doing, that's why you can take this atmosphere and put it down. So when you put it down, it only sees what's coming directly into the meter itself and that's why that's there. So you can do that. The problem with this, let's say I'm entering this light. What would happen if I had a really bright thing behind Quinn? Well this light meter doesn't see that at all. Then it would be up to me to meet her, the thing behind her figure out how bright that is meter the light in front of her and a just like we did before with our fake son, which is pretty cool. Okay, so I think what we'll do is we're gonna rewind, we're gonna start with T. T. L metering and see how we do t tl metering would famously get this scene wrong because this is a white background, we have a bright uh can I say white skin, very, very white skin, almost snow white skin, freaky white skin. So it would probably under expose this, but we're gonna see what happens. So what I'm gonna do here is I have my light turned on, I have a remote control and Ellen chrome remote control and I have it in Tt L. Mode and I need to make sure all my values are at zero they are okay so I have no exposure compensation, Nothing is happening. This is all at zero. And what I'll do is I have my camera set to manual mode. My camera is in manual mode it's set to 160th of a second. That's a little bit slower than sync speed on the R. Five here but it seems to work great for studio lighting. I have my eye so at 100 so you always sit your sync speed or your camera's shutter speed to a certain value usually 1 60 or 200 to around there and then you set your S. O. To a value and then your aperture is what you care about in the studio. Take my studio lighting essentials class to get more details on that. Okay so what I'm gonna do Is I'm going to tell my flash what aperture I'd want to use. So I'm setting my camera to f. 10. And so with T. T. L. Mode you set your camera to the values that you want to use when I take a photo. What will happen is my transmitter is going to transmit to this light and the light is going to flash. The light will hit Quinn it will come through the lens. The camera will go okay now I know how much light is coming from that flash. It knows if it needs to be brighter or darker. It'll make those calculations, it's gonna send a second signal to the flash. The camera's shutter will then open, The flash will fire a second time, but this time with the shutter open and you get a proper exposure. All of that happens so fast. You usually don't see it. Sometimes in video you might see. Boom, boom, this really quick to flash thing. But the first flash called the pre flash is measuring the light. The second flash is making the exposure. So I have F 10. My camera's gonna tell my flash to be bright enough to have a proper exposure at F 10. Let's see how it works. So I took a photo and as predicted it's under exposed, it's under exposed. We can look at this, we can look at this history Graham here, you can see it's underexposed. This is one of the reasons I don't use t T L much. Why is it underexposed? Well, this is all white. This is all white stuff and our camera's meter expects white. Well expects the average of all the values to be middle gray. So it's under exposing everything and I have my camera set to face priority metering which let's zoom in a lot. Now Quinn is white white white. So it might also be Quinn's face. Yeah, so I'll do that and even that is underexposed, you can see here under exposed so it's not doing a great job of metering this light. So what I can do here is I can go in to my group, this is group A. I can set exposure compensation. So what I did is I told my camera to take what it thinks is right and increase the output of the flash by one stop. So I've had to override what it thinks is, right? And let's try that again. So we're still at F 10 exposure compensation. Flash exposure compensation is now on and now look what happens when we bring that in, it looks like the color temperature is off but the exposure now looks correct. And so I'll take the that off, but you can see the difference between the first and the second shot. The first underexposed shot was what the camera thought was right. The second shot is what the camera thought was right plus one stop. So I had to tell the camera you're an idiot that should be white, not gray and override that. Okay, so that is that is how t tl metering works. That's how that's one of the reasons I don't use it much but let's just do an experiment. I'm gonna take my flash exposure compensation and I'm going to put it back to zero. In other words, I'm turning that off. Okay, so there's no flash exposure compensation at all. I want to try something because we have face priority metering on, we're going to have um we're gonna bring this out, so Quinn, I want you to walk about five or 6 steps forward. Yeah, keep going. There we go. Now. I think now we should get a different result because now the background is so much farther away, I think the camera might ignore it since it's so far away. Um so the first time she was very close to the background, I think my there we go, my tripod is failing. Okay, so let's see what happens when we move from the background. Just a little bit, no exposure compensation going to take a photo and wouldn't, you know that exposure is correct. So the interesting thing is um when you have a lot of white or a lot of black in an image, the T. T. L. Even with face priority metering tends to get things wrong. Um And so what I did was I just added some separation to the background and then it got it right. I didn't change anything in the camera or the flash. All we did was we moved Quinn forward and things changed radically. This is why I love using a light meter because it doesn't care where Quinn is, it doesn't, it doesn't care if she's close to the background are far from the background, it's just looking at the light that's actually falling on her and it's making a judgment, it doesn't have to do all the averaging of the environment, it just looks at the light itself. And so what we're gonna do is try again. So Quinn go all the way back there to the background, I'll move this back and so what we're gonna do now is we're going to shift to manual mode on the light itself. So what I'll do here is I'll take this. So I've put my remote in manual mode. In other words, the flash, the camera is no longer gonna do T tl metering, do the pre flash. It's not going to send a signal to the flash to tell it to be brighter or not. I'm going to tell the flash whatever power it should be based on my meter reading. So all this is doing is is just sending a signal to make the flash fire. That's all it's doing. Okay. So I'm going to go and I'm gonna meet her Quinn now. Um, you're probably wondering how is the flash firing if I'm pushing this button on my light meter? Well, I have a radio in this meter that sends a signal to the flash that tells it to fire. I can also control the flash from my light meter, which is pretty cool. So that's one of the features of this light meter. They love, This is an 8:58 D. you psychotic meter. So what I'm gonna do now is I'm going to come around here, I'm metering And that says F- eight, I want to shoot at F- 10. So what I'm gonna do is I'm going to increase the power of my flash using the remote control in my light meter, I'll meet her again. That's F 11. I overshot it just a bit. I'll bring that down Now it's F 10. So I changed the power of the flash manually using this remote control. So I said, I want to shoot at F 10. I metered, it wasn't bright enough, so I increased the power, I overshot, it made it too bright. I came back down, so I just changed that until it said F 10, which is basically what the camera's doing with with T. T. L. But it's doing it at a fraction of the second, it's telling the light which power to go to. Okay, so my light meter is now telling me F 10. My light meter doesn't care that there's a white background or a great background or whatever. So now I am shooting at F and I'm gonna try to shoot this a little wide, which means the corner of the flash is going to be in the photo, but I'll take a picture and look, this is a correct exposure immediately. It's just right, so you can see the light fall off if I assumed in here on Quinn just a little bit to get rid of that flash. I think you need to move the flash a little bit. There we go, Here we go. Um here we have a shot of Quinn color temperature needs to change a little bit of course, but the metering is correct and it's just correct right out of the box. I don't have to really change anything or do anything, it's just done. So I'm gonna show you one more thing that I promised I would show you, I sort of forgot and that is how to lock the metering if you're shooting in Tt L mode. So what I'll do here is I'm gonna make sort of a difficult meter reading that T. T. L. Would get wrong most of the time. So Quinn, I'd like you to come step forward just a little bit, something a little bit farther, a little bit more. There we go, perfect. So I'm gonna light Quinn from the side and so maybe we can get a shot from camera two, we can see this, you can see that this is really side lit. So I'm gonna, I'm gonna shoot right here and this is gonna illuminate side of her face. On the other side. Should fall into darkness. This is something that T. T. L. Might get wrong and so what I'll do is I might come over here and shoot a shot. Uh that's easier for t tl to get right, I'm gonna lock that. In other words, I'm going to say now that we know how bright this flash should be, don't move, no matter where I go with my camera, don't change anything. And so let me show you how this works. So the first thing we need to do is get a correct uh meter reading. Sime going to go back to T. T. L. Mode. So my remote is in T. T. L. Mode. In other words, my flash is gonna do the pre flash, it's gonna send that through the camera. The camera's gonna make a judgment, tell the flash how bright it should be, all that stuff. So to uh let's just do this normal where I'm just shooting straight on and let's take a look and see how the the metering worked. Did a pretty good job, I have to say, did a pretty good job there. And I think that's because it's using face priority metering. That's pretty good. So uh watch what happens though. So that's that's right, that's a correct exposure. Um I like that. But what happens if I walk on the other side? So. Exactly. So I'm shooting into the light now, so, if I do that now, looks what the camera does the camera says, Oh, I need to be exposing for this flash and under exposes. Quinn. I don't want the camera to do that. So what I'm gonna do here is going to go back to this first shot, the very first shot. Okay, so we shot something that looks correct. That's beautiful. I love that. And now what I'm gonna do is I'm gonna go to my cameras uh meter meter. Yeah, I'm gonna go to my camera's remote, not meet her. And I'm gonna tell the remote to go to manual mode. And as soon as I do that, I've locked in that value. So the flash isn't gonna change values anymore, it's just locked in my cameras on manual mode. My flashes now on manual mode, it remembers the value that I last used. So no matter what I do, it should stay the same on some uh remotes for other brands than Ellen Chrome. I think the button, it's called TCM. Um there are other ways to do that on like pro photo and some other brands. There's away on the remote to say lock in that value. So check out your user manual, I don't know every single brand what that button is called, but it's on almost every single brand now. So now what we're gonna do, I'm gonna validate that we have the correct exposure so that is in manual mode and so yep, it's the same value. But now let's do what we did before where the camera got it wrong, I'll shoot that and now look what happened is if you look at Quinn's face. So go in here, look at Quinn's face, it is exposed correctly. That skin is exposed correctly. This flash is overexposed, but the camera didn't try to compensate and underexposed. quint. In fact, I'll go back here and we'll do the whole shot and you can see that the values are staying the same even though she's backlit, those values are staying the same. And so I've locked in that exposure. Now I can just play with these shots. It doesn't matter where I go, The value will be the same and try not to trip over my own two ft. I'll go behind here. It's like that I'll shoot here. Okay, so the exposure values are staying the same even though I'm moving all around and doing wacky stuff, that would not be the case. If I was shooting T. T. L. Mode, it would try to re re adjust the exposure every single time. In fact, let's just look at each of these side by side by side. There you go. Yeah, look at Quinn, don't look at the light in the background, it works fantastic. Okay, so now that we know about exposure creatively correct exposure. Some of the different ways that we can meet your light. What we need to do is we need to revisit that we started with and that is why so many light modifiers. So let's dive into that question. Next

Class Materials

Bonus Materials with Purchase

Bonus YouTube Videos.pdf
Frio Grasp Mini Discount.pdf
Pop Quiz.pdf
Sample Photos for Pop Quiz.zip
Tether Tools Pro Kit Discount.pdf
Tether Tools Starter Kit Discount.pdf
Understanding Light and Modifiers-presentation.pdf
NanLite_WALLACE5.pdf

Ratings and Reviews

user-a07413
 

Wow, Impressive with lots of information on light modifiers. Lots of variations of use and the bonus material. Mark is very good as a teacher. Glad I purchased the subscription plan so I can see the other Mark Wallace classes. Now to go to work and use the information.

Paul
 

I've heard much of this before, but this class really does a good job explaining and demonstrating the principles and techniques it covers. Mark is certainly quite knowledgeable, and he makes the material accessible and easy to grasp. It does cover quite a lot of ground, and while others may go into more detail, I think this class is great for building a good foundation.

Mario Furtado
 

Mark and his crew did an excellent job in this class. Now I am eager to see Go-To Lighting Setups and Studio Lighting Essentials. Congratulations.

Student Work

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