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Lesson Info

Metering, White Balance, and Depth of Field

Okay, so the procedure for metering is fairly important, and let me just mention it here. The procedure for metering in manual mode is you choose the aperture, 'cause that's number one. That's gonna give you your depth of field, which I'll talk about and explain in a minute, and then you're gonna apply the filter 'cause you do wanna make that decision then if you can, if you can afford to do that and know it. Then apply the filter, 'cause then you're gonna be able to dial in the shutter speed, okay? That will be the next step 'cause that's what's gonna be governed. Your shutter speed will be governed by the aperture you choose and any filters you put on the lens. And then, you basically review the meter in the camera and then take the exposure and check the histogram 'cause that's gonna finalize your procedure for looking at exactly what your aperture, I'm sorry, your accurate exposure is. In manual mode, this is your tool, okay? You're gonna have the underexposed side of the graph and...

the overexposed side of the graph, and you are responsible for lining that up in the middle. 'Kay, and you're changing the shutter speed in the case that I just told you to get this line to line up in the middle. It's that simple. It's not that hard 'cause you point the camera, and you put the filter on, and you line that up with the shutter speed, and that's gonna be your accurate exposure. So it just takes a little longer. All right, so metering in manual mode for capturing motion. Well, you're just gonna reverse and not use aperture. Now you're gonna use shutter speed. Okay, so if you got a wave coming in or a waterfall, you're gonna choose that first, and the shutter speed will vary based on how much detail in that moving water you want. And then apply the filter, dial in the aperture, review the meter, take the exposure, and check the histogram. Okay, so all those things are gonna be the same. This is an example of where I wanted to dial in the shutter speed 'cause I wanted some movement with the wave coming towards me. And I did not have a filter. I was on vacation in Hawaii, and I think I only had ISO because I didn't want a longer or shorter shutter, no, sorry, I wanted a greater depth of field because that sand in the foreground was only three, four feet away. I wanted that in focus and that lighthouse, which is way off in the distance out there, in as much focus as possible. So I wanted maximum depth of field and the shutter speed set, and that was the reason I chose those settings. Okay. So a couple things when you're doing this that will trick the meter, and it'll set you off and you might wonder why. So I bring them up because they're pretty standard. One is anything white, okay, I just write down snow here, but a big blank whiteboard will do the same thing. Clouds, that'll trick the meter. A backlit scene will trick the meter. The light gets low, you're looking into the sun, it's gonna be hard to meter in that situation. And then, of course, what we're using recently is a 10 stop neutral density filter. And the reason that tricks the meter is it just doesn't work. I don't know exactly why, but you have 10 stops of density in front of the lens, and so you have to be able to calculate that exposure. Some cameras work, some don't. 'Kay, so if you have a 10 stop, you have to test that. So here's what's happening. Your camera is looking at this entire scene from black to white and it's trying to get those settings set so that what you end up with is representing 18% grey. That's what the camera's trying to do. It's trying to put all that detail as close to that middle or grey as possible. If you take this picture of, we'll call her Shirley, which is in the studio, we use it for color calibration. Then you're probably gonna get an accurate exposure 'cause it's got perfect blacks and whites and greys and colors and the light's just right for the camera. Under that situation, it's going to work. Everything's going to be just fine. Does that happen out in landscape? Very rare. I might give it to you that if you look in the northern sky in the middle of the day, the blue sky, that's actually 18% grey. But, typically there's a cloud or something interesting, otherwise you wouldn't be photographing it. And so what I want to point out is that the camera is trying to take this part of the picture and turn it into the middle of that scale just like I showed earlier. And so your job is to compensate so that it turns brighter. So there's the camera default on the right. You're going to change and set your camera so that you add one stop of exposure so that you get the accurate exposure to represent that gradation. And that's called compensation. In this case, I'm going to show you a sequence of brackets and the histogram that goes with it. This is essentially two stops underexposed and what the histogram will look like and then one stop underexposed, a normal exposure, and overexposed by one stop, and then overexposed by two stops. What you can do with bracketing is instead of just using it for HDR, it's a great way to set the camera so that you can take multiple pictures in case you're doubting yourself. Bracket, for the reason it was originally intended to work for, and that is forgetting the accurate exposure if you're not confident. But there's no reason you shouldn't be confident after you know this information, right? So one of the things, the only thing you want to look at when you're looking at the histogram, I already told you one and that is the edges. So aside from the edges being critical, you have this thing called ETTR which is exposed to the right and what that means is you want to get, in a critical situation, you want to get as much data as far right as possible without having that data go up the right side of the chart which would be clipping. So that's what ETTR means or is referring to. And the reason for that is from the grey point of the middle of the chart of a greyscale of our dynamic range, the camera's actually recording a much higher bit depth. So just remember a lot more better data on the right side. If you underexpose and you have to compensate in post, then what you end up with is noise. And that's what I've done here as an example. You basically have a picture on your left that was three stops underexposed. And online, if you post this on Facebook, it's probably going to look fine. So no fear. But if you go to print this, you can see the proper exposure's on the right, if you go to print this, you're going to see the problem with this and what happens is you start seeing noise and the noise is creating big chunks of data and so it's breaking up some of the finer things of that digital file which is why you bought that nice camera in the first place. So that's why you don't want to underexpose and then over process. Another example, you can see the nice, smooth mountains in the background on the right and on the left you can start seeing what looks like specks, what we used to call grain in film but it has a very similar look. Alright so checking for blown highlights. A couple of things to point out about that. Some cameras have what's called a playback option and I think most DSLRs do now and when you play the image back, what you want to do is you want to make sure you turn it on so that the RGB histogram is showing and there's also another option called highlight blinking. We call it the blinkies. So it's a quick warning that your highlights are clipping. I typically don't rely on that in an ideal situation. Maybe if you're quick and you want a quick reference but while you're reviewing the blinkies, it's really easy to overcompensate and then all of a sudden remember your ETTR is now shifted to the left and now you're underexposed. So in an ideal situation, you really want to catch yourself metering, if I can get this to go, basically exposed to the right and don't blowout your highlights. That's it, that's your job is getting the right meter. I just want to make it that simple because in the end, and I'll talk about changing aperture and shutter speed and all that, but that's the key. That's your meter. Get that thing as close to the right side as you can without clipping those highlights. Alright so filters. Filters throws another option in the loop. The two filters that I showed you that I used when I showed you my equipment are the neutral density and the polarizer. Those are the only two filters I use. I do use various different types and sizes. With polarizer, the one thing you have to consider is that when you turn the polarizing filter to try and get its effect to maximize it, you will cut a little bit of light. So your polarizing filter will actually act as a neutral density as well. It's cutting a stop and a half to two stops of light when you apply it, alright. The max polarization is 90 degrees from the sun, and that's when you'll be blocking all the light that's reflecting off the shiny pools or whatever. That's when you're going to use it at its maximum and that's when it blocks a full two stops. So neutral density, this has become popular probably in the last couple years once they started figuring out how to make them so dark and they make them now, I think I read that there was a 20-stop ND filter out there. I don't know who makes it, I think it was a blog but essentially what you're doing is you're trying to block as much sunlight as possible to get the longest shutter speed so that you can get clouds moving and it's a really fun effect to work on but this is just something you want to be aware of when you use a ND filter, okay, especially at 10-stop. What happens is it blocks all the light out except for the UV light and so your file will come back and it will look blue but it is a simple fix. It's just a change of the white balance in post. If you want to deal with it in camera you can actually create a custom white balance for it but in the end, it's easy to change in post when you go into Light Room. Alright neutral density has completely eliminated my need for our bracketing as well for split grads. So I don't use the split neutral density grads which you use if the sky is brighter than the ground below the horizon. It is a handy way to throw that in front of the lens and block about between one and two or three stops of light from striking the top of the sensors, top of the scene. And now when I bracket the scene, I'm basically getting two stops underexposed for the sky and two stops overexposed for the ground and I'll show you guys how tomorrow to blend those together and then you don't have this big line through the middle of the picture even if it's graduated, you still don't have that one single place to put that density difference. So I don't use split grads anymore essentially. The one effect that is a problem when you're using filters, especially with landscape, wide angle lenses, is vignetting. And I showed you guys the filters I use just so that we don't have vignetting. They're fairly big. They're not quite lifesize but they are big. And what you want to do is often times, you want to stack these filters. And so instead of making the filter big enough to not vignette by itself, you also want to put two filters on and in many cases I'm using the polarizer plus the neutral density. And that's one of the scenarios that I use quite often in water landscape because I want the moving clouds and I want the beautiful water. To see through that water, polarizer is giving me that beautiful green plant that's underneath the water. Without the polarizer, I wouldn't see any of that green. But of course at 16mm you can see a little bit of vignetting. So a couple things you can do. One is you can just zoom in if you have that lens. I have the 1424 so I go into 18 and then I get rid of the vignetting but if I don't want to do that, basically you can go into post and those little tiny black corners that you might be fretting so much about, they come right out in post and you can even do most of that in Light Room. If you want to get tighter and better at it, you can do it in Photoshop. So don't worry too much about those little black corners especially if it's an area like sky. So the RAW file because all this stuff we're talking about is getting the right exposure and using aperture, shutter speed, and ISO but really, the critical element to all this is that you change your file type in your digital cameras to RAW because you've got all these things to think about in the tech trinity if you shoot a RAW file, then you're going to eliminate a lot of other choices that you're going to have to make in the field. White balance, picture style, picture control on a Nikon, sharpness, color space, other features like vignette control now some of those things are in cameras, image size, some cameras though do offer now a small RAW file so you can change file size of a RAW. But essentially I shoot RAW files only. I have not shot JPEGs. A good scenario for JPEGs is if you're just taking fun pictures and you're not too worried about all the post processing. Camera profile, that's something that is important. It's not at the top of the list of the must do's but eventually you're going to get to the point where you're going to start seeing color casts from your camera in certain areas. And the way to get around that is X-Rite makes something that is called the ColorChecker Passport and that product is under 200 bucks. And what it does is you photograph it in daylight and it's going to take a scan of all that, compile a new camera profile, and then it's going to take one that you can use in Light Room to make up for the difference between what it should be and what the camera sensor is recording. So on the right you can see a little more saturation in the green grass and the blue sky and that just gets you one step closer to where you want to be in the end. Aperture, alright, so what are the things that you affect with aperture? Well of course, exposure, diffraction, I'm going to talk about that, depth of field, and hyperfocal distance. Those are the buggers that are so complicated. First of all aperture is at a wide open aperture or a big aperture, you have F/2. which is just simply a larger circle, letting more light in the lens. You go all the way down to F/16 or 22, the circle just gets small. So it's the amount of light coming into the sensor. And there's just an example. The nomenclature is stopping down means that you're going from a wide open aperture to a smaller aperture and you're losing light. So now all you guys know when I yell at you stop down, then you know exactly what I'm talking about. Opening up, the exact opposite, you're going to open up that aperture, and that's all that means. You're going to go from F/22 to F/16, 11 or and just let in more light. Same thing, it's all governed based on the same principle. A stop of light. F/5.6 on the right, 4 in the middle, 2.8 on the left. This is exactly a stop of light difference between all those settings of your aperture. Diffraction, diffraction is something that happens as you start stopping down. So this is a Edmond scientific lens chart and you don't have to do this, go online, you can see many examples of this where people have already done it for you. It's pretty amazing what's online now. But if you really want to see the characteristics of your lens, sometimes the manufacturers vary the quality of each one just slightly. These are about 20 bucks and you set your tripod up right in the middle of it, take a picture of the chart, and you take one at every different aperture and that's what I've done here and what happens is is when you stop down, this is a Zeiss 15mm lens so it happens to every lens no matter how much money you spend on it. At F/4 and there's one at F/ and you can see just the very center of the chart there is starting to get fuzzy. That's from diffraction. Typically, you don't want to stop down as much as possible. This is a Nikon, basically same thing. F/4 on the right and it's much sharper and crisper than F/22 on the left. These are 100% enlargements out of Light Room with no sharpening applied in post. Have you heard this before? F/8 is great, don't be late. But essentially it's true because at that point, that's where your lens is at it's sharpest. Now there's some lenses like the 2870 to 200mm lenses, those are going to be the sharpest at F/5.6. So it really changes based on the lens but essentially it's two stops to three stops down from wide open. So if you have a 28 lens, then it's going to be 5.6. But like I said some of these wider angle lenses, the 1424, F/8 is very comparable at F/5.6 and and what you get at F/8 is a lot more depth of field. So F/8 will actually capture most of your scene in focus 80% of the time when you're out taking pictures 'cause most people don't get that close to something. So just in general, remember F/8. So depth of field and hyperfocal distance, this is the bugger that we struggle with as landscape photographers but think of a couple things. In this case, depth of field. There is only one focus point between the lens and infinity. The rest of the depth of field is just the amount of acceptable sharpness that you'll put up with as the photographer. At F/2.8, your depth of field is very narrow. At F/22, it's much wider and so when you want to get something like this table in focus and you guys in focus with a wide angle lens right here, typically you'll hear somebody is stop down, use F/16, and then the next question that comes up is where's your hyperfocal distance. Where are you going to focus between this table and the background? And so some of the things that affect it affect depth of field: your focal length. The longer the lens, the narrower the depth of field at the same aperture so F/8 on one lens is going to be a little less depth of field on a more telephoto lens than on a wide angle lens. Just a little graph here's 24mm lens, F/8, and you can see at 50mm that depth of field is a lot narrower. So hyperfocal distance is the closest distance at which you can focus and still have acceptable focus to infinity. So remember when I said there's one focus point? This is that point but what it does, at a certain given distance from a lens, is give you that range of depth of field so that infinity's in focus and the closest subject to your lens is in focus. So a couple little charts. The sensor plane is what's critical. That's your focus point and the depth of field. So in this case the sensor plane is on the far left, focus point in the middle, and there's infinity. There's your depth of field. So it's this given depth of sharpness out between the lens and infinity. Just to give you another graphic. There's 5.6, F/8, and F/22. Remember I showed you that picture I took on the beach. Well that's what was happening. I had the wave in the foreground in focus, set my focus point or hyperfocal distance, and then I had infinity in focus as well as the wave in the foreground. So same thing happens in F/8. You just have to extend that focus point further away from the lens. Here's a couple examples. F/16 with an 18mm lens, just so you get a good general picture of this, closest point is this rock down below me, maybe four, five feet away, then the hyperfocal point is about seven or eight, depending on where you are, feet away, and then infinity of course. And so that's the hyperfocal point in that scene. This one's very similar. A 24mm lens, again you have the closest point and the hyperfocal point is a couple feet away maybe, maybe three feet, and so that I get infinity in focus as well. A couple things to note about hyperfocal distance. Interesting numbers. The distance from one to two which is the beginning of your depth of field to your hyperfocal point is a third of the distance from that point to infinity. Thus we get that same focus a third of the way into the scene. The problem is I don't really understand that because it's not really a third of the way into the scene, it's a third of the way into the depth of field. That's what's critical and that's the point you need to find 'cause your scene could be anything and you don't know how far you are away from the first subject when you consider the scene. The other interesting part about hyperfocal point is that the beginning of your depth of field is about halfway between the sensor plane and the hyperfocal point. Just something to make note of when you're out there looking at depth of field. How to determine that depth of field for each lens. We're going to look at determining focus point while stop down that is acceptably sharp at infinity. So how do you determine that? I'm going to show you a video in just a minute. This is that hyperfocal point and that's the really tough part. Here we go. What I've done here is I've set up the newspaper and the camera in a scenario that would be typical of a landscape that you would take to capture the near far. Some real dramatic foreground, maybe some rocks or waves or something in reality other than a newspaper. And you want to get that in focus and you want to get infinity in focus and so one of the hardest things to do is figure out how much depth of field you have with a lens and you obviously have the hyperfocal distance to determine and that's what we're trying to do here. This exercise gives you the ability to really visualize it without knowing the calculations of the hyperfocal distance. And what you want to do is you want to be able to set your camera down and know that with this lens, you're going to have so much depth of field from a certain distance from a camera to infinity when you focus the lens at a certain spot which is the hyperfocal distance. And so the best way to find out hyperfocal distance is by using a couple things in the camera. Number one, most cameras now have live view and so I've turned on live view and they have the ability to zoom in and move that enlarged region around until you can find the spot that you're looking for. I'm utilizing live view and looking at certain areas. I have the camera set to manual mode and manual focus. I also have the lens which is a 14-24mm lens, I have it at about 15, it's not as wide as it goes. I think the lens is a little bit sharp for 15. And so that's the typical scenario that I use this lens in at F/16 so because I do that, I stop my aperture to F/16 right now, my ISO is 100, and I'm basically going to go in and find infinity like so. And I'm going to zoom in on that tree way in the background. Depth of field is best understood if you consider that there's only one place between the lens and infinity that's in focus at a time and the depth of field is really that region of area that's acceptably sharp. So that's literally what we're going to do here. We're going to look at this picture at F/16, and right now it's focused at infinity. And as we manually focus it closer to us, you can see the picture going out of focus. And so if I go all the way back to infinity, there's a distance in here where it starts getting less sharp and right about in there is where we have to make our minds up that that's acceptably sharp at F/16. And on this lens, it happens to be about two and a half feet but we're going to just double check that and the way you do that is you zoom out all the way and then you have the camera in, you change it to aperture priority, and if you change your aperture setting to wide open, and you scroll down to about two and a half feet, what we're going to do is zoom back in and look for that spot that's in focus and it's pretty easy to tell because at F/2.8, our depth of field is so shallow and so you can see on the ruler what part's in focus here. There's two feet, and it starts going, well, that's a good example, it starts going out at about two and a half so if you come back here, we get a little depth of field it looks like 22 inches. Our lens looks like it's focused at about two feet. Scroll in a little further to see, you can see how 27 inches is out and 21 inches is out. So we'll go right in the middle and then you can take something, anything, you could use a Sharpie in this case, this chapstick and we'll just put it right there so we know that that's our focus point. That's our hyperfocal distance. And I only do this because it gives me a good visual because if you come down to a situation like this along the ocean or wherever you are, it's good to know that that's your focus point and you can basically then determine without a tape measurer okay about two feet in is where I'm going to focus at F/2. and then you simply stop down and take the picture. So it can be that simple. Now for this test for you guys, I want you to take this picture at every aperture so that you can study these files and then determine if that's exactly what you want, if that's the right point. So pull out my remote, and that was at F/2.8, and now we're just going to stop down to F/4. 5.6... 8... 11... 16 and we'll do 22 as well. When we go back and we look at these files on the computer, we can decide well, maybe two feet was too close if our trees were slightly out of focus at 16. We might want to change that to 28 inches or two and a half feet. It's really a lot of fun. Trust me. Another way to solve this problem of this much depth of field is we have something that's closer than two feet to the lens or the sensor plane all the way to infinity and that is focus stacking. And since we're all set up, I'm going to show you how. You basically scroll all the way down to the foreground, zoom in, get that in focus, and again we're in manual focus and the sharpest point remember is F/8 and so F/8 is great, don't forget that. That's the sharpest point in the lens, that's where there's less diffraction, and so we're going to take a picture with our remote. F/8 on the foreground and then we're going to scroll up here to about two feet and we're going to zoom in and we're going to refocus and we're going to take another shot and then we're going to scroll up and I think three exposures is usually fine but I'm going to do four just to show you that it's possible and the more of these you do, the more information Photoshop will have to work with, and then you scroll all the way up to the top and zoom in and this is where you'll need to refocus again. You can see how it gets much sharper and then take your last shot. You take all those files, throw them together into Photoshop and it'll stitch 'em together with the sharpest point utilized in all the files.