Sensor Size - ISO
All right, so next up is the ISO, which is the setting of the sensitivity on the sensor, and where we're gonna wanna set it for different things. So, ISO. This is the sensor sensitivity, and the ISO comes from the International Organization for Standards, which has gone about setting specific standards so that when you talk about ISO 100 on your Fuji or your Nikon or your Sony or whatever, we're all kind of talking the same language. There's an equal thing. Now, something interesting has happened recently, if I diverge just slightly. Some people, right now, are getting mad at me. Does anyone know why? (audience murmurs) Because I said I-S-O, and they, no, it's eye-so! I say it's I-S-O. No, it's eye-so! The International Organization for Standards, at some point in development of their website decided, oh, we should call ourselves eye-so, or you should say it as eye-so. Well, it doesn't really matter. You can either say I-S-O or you can say eye-so. It doesn't really matter. When I grew ...
up, anyone who said eye-so was somebody that was a complete knob rookie in photography, and so I never wanted to be somebody who said eye-so, but there's a lot of good reasons why you could call it that but, you know what? Either way, it sounds pretty close. If you say it real fast, ISO, (audience chuckles) that's what it is. Okay. It doesn't matter. It's all the same. All right, so for most cameras, and let me stress-ify the most, not all, 100 is the base sensitivity. So, these sensors are designed to receive and produce the optimum results with a certain amount of light. It doesn't want to be too much, doesn't want to be too little, just this right amount of light and it's gonna produce perfect colors and resolution, and everything is gonna be fine and dandy. You can crank that up a little bit like the brightness knob on your TV, and you can double it if you want. You can make it twice as bright as 100 by setting your ISO to 200. Now, there are some cameras, the native sensitivity is 200. It's just what it is. There's some cameras that are 64. Different numbers for different cameras. 100 is the most common. And, we can crank it up to 400 and 800 and and on and on and on and up. 6400 is the highest you're going to get to in most cameras keeping reasonable results, which we'll look at very closely here in just a moment. But the key thing to know, is what is the base or native sensitivity of your sensor? And you're gonna need to go in to your sensor controls, and what is the lowest setting that doesn't have something other special going on? We'll talk about here in a second. But it's basically the lowest normal setting in your camera. So, some cameras will go all the way down to 32. Some will go up to three million, two hundred and eighty thousand in ISO setting. Optimum image quality is gonna be on the lower numbers. So, if we go from 800 to 1600, we're moving a full stop, so it's kind of like shutter speeds in the sense that we're doubling the numbers and we're doubling the brightness levels. If you go from 800 down to 400, that's a full stop in the other direction. We're cutting the light in half. It's gonna be twice as dark or half as bright, however you wanna think about it. The medium and higher end cameras will also offer you the option of setting third stops, and these are just options for you to be very precise. A lot of times, people might set a third of a stop so that they can achieve a particular shutter speed or aperture, but there's a number of people who have third stops that turn it off, just 'cause they quickly wanna get from 100 to and they can do so in less clicks without going by all these third stops. And so, whether you have them or don't have them, it's not a big deal. Once again, I'm gonna be showing you the full stops just so that we don't have quite as many numbers on screen. Another few options that you might see in the ISO settings of your camera is an L or a low setting, or an H and a high setting, and what this is, is the ability for your camera to go beyond the standard range, either low or high. A high one setting, over 6400, means one stop higher than the last number, and we know we just like to double things here in photography, so, high one would be 12,800. High two is double that again, which would be 25,600. Low one is gonna be, think about it, 50. Just cut it in half. And so, they should just put numbers there. That would be totally fine, if they just put numbers there. What I believe, and I do not have factual proof on this, but I strongly suspect it's true, is that when you go from 100 to 200 on up to 6400, there are physical, quantifiable changes in the sensor and what it's doing, the way it's processing that information. Something physical that you can measure. The high and the low settings is gonna be a software adjustment as opposed to a hardware adjustment, and they typically tend to change a little bit more notably in quality when you slip into that extra high setting here, which we'll see more of here in just a moment. Now, there is the option of auto ISO, where you let the camera choose for you. Now, it is gonna choose a number for you. It's not no number. It's gonna choose a number for you, and so what it's doing, is the camera is looking at the light meter on the camera, looking at how much light is coming in, and if there's not a lot of light, it's gonna change the ISO. So if we can imagine a situation where the light gets darker. Well, the camera is gonna go, let's adjust the ISO, and it's gonna crank up the ISO to compensate for the lower light. And if it gets bright again, well then, it's gonna take the ISO back to a lower setting, and it's just gonna go up and down the scale according to what's going on. Now, when it comes to shutter speeds and apertures, this may or may not work well with what you're trying to do. And so one of the other things that you can be doing at the same time, is have your camera automatically setting shutter speeds. We're starting to hand over a lot of control to the camera at this time, and for somebody who wants very particular control, this might be a bad thing. So what's gonna happen when we have both of these set to auto? Well, when it gets brighter, it's probably gonna go and use a faster shutter speed, 'cause that's what it can do to lessen the amount of light coming in the camera. As it gets darker, it'll lower the shutter speed, and then there's a very important point where it's gonna stop going with shutter speeds, because there's gonna be a minimum shutter speed either built into the database of the camera or that you have manually inputted that said, don't use anything lower than, in this case, a 60th of a second to use. If you get down to a 60th of a second and you need more light, start changing it with the ISO. So if it gets darker then, you would change it with the ISO, and so it's getting this balance and this break point set right is important depending on what you're shooting, 'cause if you're shooting action, a 60th of a second may not be the right shutter speed. You may wanna switch it at 250th. But this is where a lot of cameras will have it inherently. And if you don't like this minimum shutter speed, let's say you're handholding and you're a really steady photographer. You might wanna have a lower shutter speed, like a 30th of a second. Okay, let's go down to a 30th and then switch over to the ISO, or you might go down as far as you feel comfortable. So, you could set in what you think is the lowest shutter speed that you can hand-hold. Now, for me, hand-holding, eighth of a second, maybe I could do that. But if I'm shooting action, I might be up at something higher. Depends on what you were shooting. Now a further wrinkle in this, and we're gonna dive pretty far down this rabbit hole, if you will, you can have an auto minimum shutter speed set. So now you don't have to worry about setting this. What it does, is it looks at the lenses you are using and figures out what's appropriate for somebody using that focal length lens. Do you remember back in shutter speeds when we talked about lenses? You need certain shutter speeds with certain lenses. The camera just figures all this into the game now. If you have a 24 to 120, it's gonna say you probably need at least a 30th of a second, if you're at the wide-angle 24 end. You're out at the telephoto end, or a little bit in the middle, you might need 60, and out at the telephoto end you might need 120. So the shutter speeds would automatically change, perfectly, as you zoom the lens back and forth. And so auto minimum shutter speed is a nice thing to have, and a lot of the new cameras have now added that in, but it's buried pretty deep in the menu system. All right. We're diving down the rabbit hole, and there's one more room to go to. All right? And that is, you can now adjust where the auto will set the shutter speed for you, because it's looking at the focal length of the lens. What if you're better than that? Or what if you're worse than that? You want something slightly different than this. You can go into a little calibration tool and say, I wanna have a little bit slower shutter speed by one, two, or three stops, or maybe I'm shooting action and I need a faster shutter speed than what the camera would automatically give me in this case, and so this is definitely a more advanced setup, and so we've exited the world of basic photography for the moment here to talk about how this auto shutter speeds affect and work with auto ISO. But let's take a look at what ISOs look like at different levels. This is one of the most popular cameras on the market right now as far high-end professional cameras. This is about as good of results as you're going to get in this day and age with image sensors. What you will notice, is on the top row, we've got a lot of very clean results. We can get very clean images up through 1600. If we jump down to the worst image at 100,000, this is what you get with most cameras when you set it to the highest ISO that it will go to. In fact, what I have found is my rule of thumb, is the top two ISO settings on every camera on the market are garbage. There's a few cameras that there's exceptions to the rules where it goes more or less than that, but for the most part, the top two ISOs on your camera are terrible in image quality. Why are they there? They're there, sometimes, for scientific reasons. Sometimes people aren't trying to take pretty pictures. They're just trying to record something. When my car was getting broken into in the middle of the night by Bigfoot, I needed a camera that could crank up the ISO, and so for those emergency situations, yes. We're likely not to use it on a regular basis, but it's there if we really, really need it. So, the break point of how far can we go, which was one of the questions that we had coming in, will depend on what your standards are for printing, how large are you going to print, when was your camera manufactured, what size sensor and exactly what model do you have. And so I'm not going to be able to answer that, but I will say that for quite a while, everything under 800 has been quite good. Like, virtually no difference than 100. But lately, 1600, 3200 have become kind of clean. For quite a while, my upper limit was 6400, but I think things have improved over the last several years. Now, 12,800 is looking as good or better than 6400 did several years ago, and so these are just gonna continue to get better for the rest of your days. And, how often do you need to shoot at these higher ones? It depends on what you're doing. So, the ISOs that you're realistically going to use, most of the time, are gonna range between 100 and 6400. So, let's take a look at some photographs and look at what ISOs I set with them and why I set them. We'll start with ISO 100. When I'm doing landscape photography and my subjects are not moving around and I'm on a tripod, and everything's very well controlled, I'm going to choose ISO 100, 'cause it's gonna give me the best image quality possible. The other little background thing that's going on, is I can use any shutter speed I want. Whether I photograph this at a 60th of a second or two seconds, you're not gonna notice this. Now maybe if you zoom in to the waterfalls, you might see a little difference then, but I don't mind a little bit of blurs in my waterfalls in this type of shot. And so when I shoot at ISO 100, the beauty is, is that I can zoom in and I can see with really great detail what's going on, and we don't have that noise problem in there. And so when I'm in a well controlled situation where I can use any shutter speed possible, I definitely wanna be at ISO 100. Okay, we've got a little bit more action going on here. Do I wanna change up the ISO? Well, let's first check our camera to see what our shutter speeds and apertures are, and under good lighting conditions, I can absolutely keep my camera at ISO 100. I'll just set a different shutter speed, and, you know, fast enough to stop the action, and so I'm trying to keep my camera at ISO 100 as much as I can. All right, now the light levels are getting a little bit lower. All right? This is when a lot of people talk about cranking up that ISO. Now, hold on a minute. Let's check two things. Number one, is our subject moving? Nothing significant. We may have some people walking across the bridges, but that's insignificant. Am I moving? Well, I'm on a tripod, so I'm not moving, my subject's not moving. I've got my camera at ISO 100, which means when I zoom in, I'm gonna have nice, sharp, detailed information, and I'm able to pick out individuals on there, because I'm still using ISO 100, which is where all of our cameras are gonna be really, really clean. So I'm trying to stay at 100 as often as possible. Do I ever go to 200? Absolutely! This is a really hard place to try to use a tripod, when you're shooting straight down. All right? I'm hand-held, and it's not really bright light, and I need to compensate for my handholding of the camera, so I have to have a shutter speed that's appropriate for handholding the camera, and sometimes that forces me to use a slightly higher ISO. When I'm shooting action and things that are moving, I really wanna have a shutter speed that stops the action, because if I get a picture that is slightly blurry to movement, it's a throwaway. And so, when I do a lot of action photography, ISO 200 frequently if I need it. Almost all the times that I'm shooting sports photography where subjects are moving very quickly, you have to go to 400. When you want to shoot at 500th and 1000th of a second, it almost doesn't matter how bright the light is. You're almost always gonna be needing two, 400 for shooting that. Now if you go into a gymnasium, ooh, gets much worse there. Handheld in a church that doesn't allow tripods. I'm going around handheld, shooting photos. I'm thinking about shutter speed, getting it set where I need it to be, and then I'm adjusting the ISO so that I get the proper amount of light coming in the camera. I was on a tripod, but I wasn't too sure about my subject. He might move and change position on me, which would ruin the shot, so I needed a shutter speed that would accommodate some slight movement on my subject here. Really fast movement, kind of getting to lower light levels in some ways, here, and so I'm needing some very fast shutter speeds, and so when you need those very fast shutter speeds, they're almost always gonna come with a higher ISO setting on your camera. When you shoot nighttime star shots, ISO 800 is just the starting point. More likely, ISO 1600 and 3200. You're also gonna need the right settings on the lens and the camera, which we'll talk more about as we get through the class, but for these nighttime shots, 1600 and up. Sometimes you need 1600 even when you're in a dance school. They don't have a lot of professional lighting all the time turned on, and so, if they're moving around quickly under lower lighting conditions, you need a higher ISO to accommodate those shutter speeds. So, hopefully you can see there is a direct relationship between shutter speeds and your ISO. Low light levels early in the morning, yeah, they're not moving around very much right now, so they could probably be captured with a 60th of a second, but I'm concerned about me. I've got this big telephoto lens that's moving around because I'm in a vehicle with other photographers, and I need to accommodate for my movements, not so much their movements in this case. We saw a picture of these guys earlier, but ISO 3200 under those low light levels. Working outside at nighttime, just by the streetlamps that are turned on. ISO 6400. It's not as clean as 100, but I am getting sharp, clear shots that I can use. Under very low light levels in an aquarium. Gotta be aware of people's movement. I need probably a 60th or a 30th of a second to stop their movement, and with the low light levels, I needed to compensate for that low light with higher ISO settings. I hate going to 12,800, but you know what? Telling them to stop the music and slow down doesn't work out in this situation. (audience laughs) And what happens when you shoot at these higher ISOs, is you're gonna get noise. And you know what? Tough. You're gonna get noise. That's gonna happen with all the cameras. It's a little bit better with certain cameras and so forth, and there's little bits that you can do to reduce this, and I'll talk about this in the art of editing section, section eight of this class, about how to deal with it once you've gotten it, because in some cases like this, there is no avoiding using 12,800. It's the only option. Would I go beyond it? (inhales sharply) Well, if I have to. And so, 12,800 once again, and it's, you know, it's gonna start marring some of the details. You're not gonna be able to enlarge these pictures quite as much, and I would like to say, I don't ever wanna use anything above 32,000, especially don't wanna go up to 25,600, but you know what? There's a coyote sitting right in front of my car here. I wanna try to get a shot of it. Really low light levels, you know? 45 minutes after sunset, and, yeah, we're gonna lose some information here. We can take that original RAW and we can reduce the noise, but unfortunately, that also reduces some of the sharpness, and so there's a very careful adjustment that you can make where you can go too far and then you have to bring it back so that you're not getting rid of that detailed information. And so, you can do some adjustment, but you can't resurrect it from the dead and make it perfect like ISO 100, so the idea is, you wanna shoot with the lowest ISO possible. All right, here is a question for the studio audience. With what type of subject does ISO not matter? And the answer is none. (laughs along with audience) It always matters! There is kind of a slight exception, and that is, a really small file size, nobody's gonna notice ISO, and so if you're posting a picture online and it's a headshot, and it's like one inch by one inch, nobody's gonna notice it there, but any sort of normal size, it's gonna affect everything that you do. Now, with modern technology, I'm able to pull up all my images on my computer and just go, how many images have I shot at ISO 100, 200, 400, and on down the list? And so, because I'm an incredible nerd from time to time, not all the time, just from time to time, I was able to graph what percent of the time I shoot at ISO 100. Now, you've seen a bit of my photography. Your photography is different than mine. Let's say you're a concert photographer, and all you shoot are concerts in the evenings out at the bars and halls and arenas and like that. My guess is that you would have a giant curve over here where most of your stuff is being shot at 16, 32, 6400. But the idea is, is that you're trying to shoot with the lowest ISO settings possible, 'cause that's where you're gonna get the cleanest, best information that's gonna be the most, malleable later on, that you're gonna be able to work with in post-production. So, for technical reasons, you set it to that lowest numbered setting. It's usually a hundred. Sometimes it's 64, 80, a hundred, 200. Those are the most common numbers. And then for high sensitivity, you'll set it up wherever it needs to be set, and the guideline is pretty simple. You keep the ISO low and you raise it when you need faster shutter speeds. And so if you're in a situation and it's like, wow! My pictures are still blurry 'cause the dog is still running too fast, raise your ISO up a step, and then you can use a faster shutter speed. All right. The next learning project is for you to do your own ISO test. I've shown you some of my results, but I'm not shooting with your camera, and you have different opinions than I do, and so what I like to do, is just set everything up to do a quick ISO test and see where my limits are in my camera, because, in my mind, I'm probably gonna have two or three little notches. One is where it's perfectly clean as far as I can tell, up to maybe 800. It may vary for you. And it's like, I don't mind using 800 at all. No sweat. I don't sweat at all when I use 800 at all. But then when I go up to 6400, okay. Feeling a little uneasy here, but I think we're gonna be okay. When we go beyond 6400, oh, I just don't feel comfortable, but I'll do it if I have to. You do what you have to do. And so, figure out what your camera is good at, what your limitations are, because you may find that, you know, your camera is good up to 6400, but you never use anything beyond 800. (snorts) A new camera is not gonna do you much good in that case.
Can you talk again about when you might use the ISO 50?
Right, so, yeah, I didn't get into that too much in this one. Most cameras, most, (hems) I'll keep that with that, most, most cameras will have a low setting of 100, or a setting of 100, and some cameras will have an extra low one or a low 50 setting. Now, you can shoot at that. The problem is, is that the range of light that you can capture is less. So, it can't capture as many brights and as many darks at the same time. So, it's at a compromise. Now, do I ever shoot at this low setting? From time to time, I'm shooting water movement, like a waterfall, and I'm at a half second. I'm like, ugh, I really wanna get down to one second. How can I get down to one second? And my lens is, I've done everything that I can there. Sometimes, the only thing that's left is taking my camera from ISO 100 down to 50. In that case, I can go with a half second down to one second, and if the waterfall or the water I'm shooting is not in really contrast-y lighting, I can do that without much in the way of lost quality. But you don't wanna naturally do it, so you do wanna be very aware of what is the base setting on your camera, do you have a low setting, and do you have a high setting, and how do you get to it. A warning for a lot of you is that, in order to get to the low and high setting, you have to dive into the menu system and turn off the little child safety locks that allow you to use those settings. It varies from camera to camera.
Is the high ISO the only determinant of noise?
No. High ISO is the biggest determinant of noise. You can also get noise from long exposure, and I do have a slide for that as well. But you can get, because the sensor heats up when you leave it on for a long period of time, you can get additional noise in long exposures, like two or three minutes, which is why we don't wanna do a two hour exposure on our cameras. That would be a bad thing for it, so I don't recommend doing that. So, usually about five minutes is the longest I would go leaving my shutter open.
From Lizzy online, who says, is it ever useful to use a lower ISO in low-light conditions and then brighten it in software? Will that yield less noise than using a higher ISO? So I guess, at some of those images where you might need the 12,800 ISO.
Right. And so, I wasn't sure when they said a low ISO if they said the low, which was like the 50, or just in general, a lower ISO.
I think it was referring to low light scenarios, so using that, in reference to, when you were talking about, well, I wouldn't wanna go this far--
Your tolerance for--
It's gonna be a trade off between noise and blur due to shutter speed. And so, it really depends on movement, your movement and the movement of things that you're photographing. If you're photographing a building that's not moving and you're on a tripod, you wanna use the lowest ISO you can, 'cause then you can just keep your shutter open as long as you want. Where things get tricky, is where you're photographing, let's say, dancers in an auditorium that's kind of low light. What you really need to do, is you need to know your shutter speeds. So, what we learned in the previous section. Okay, 500th of a second for fast human action. But maybe, if these dancers, who kind of pause for a moment, maybe I'll shoot them when they pause, and I don't need to be at 500th of a second. I can come down to 125th of a second, and then I can lower my ISO. And so there's a lot of tricks depending on how you shoot. Or maybe, I'm not gonna shoot them running across the stage. I'm gonna shoot them running towards me, 'cause I can do that at a slower shutter speed. And so there's lots of tricks. The more you know about shutter speeds, what's the slowest shutter speed you can get away with, then you can afford to use a better quality ISO setting. And so, those shutter speeds will have long reaching implications beyond what we talked about just in the first section.
All right. Question from Russ. Is there a difference between the early ASA and ISO?
So, the ASA was the American Standards Association, if I recall correctly, and they actually match up the same, and so it's the same numbers between them, as far as 100, 200, 400, and those of you who remember buying film at 100, 200, 400, it's the same thing with our cameras. So they adopted a system and they didn't need to. They could have gone with a completely different system for it. In video cameras, they don't use ISO. They use something called gain, which ends up being the same thing, but has different terminology with slightly different controls. We kept it because, in photography, we have a lot of history, and we like to kind of stay true to our history, which is why we still bring things back to 35 millimeter and their focal lengths and so forth, and so it's part of the baggage that we're carrying at this time.