Exposure Triangle: ISO
All right, then our last bit of this whole puzzle is called ISO. And ISO is, if you came from the world of shooting film, ISO is like film speed. So I remember when it would be one of my siblings' birthdays, my mom would send me to the grocery store to go get film for the party, and I would be like, uh. You know, I was like 10 or whatever. And I'm like, I don't know, 200, 400, whatever this is. Sometimes the box would have a picture of a birthday cake on it, so maybe I'd grab that one, but ISO represents, it's like your film speed. And what that really means is that it controls the camera's sensitivity to light. In the film days, that was controlled by actually the size of the emulsion, the crystals in the emulsion could control how sensitive the film was to light. So we don't have emulsion and all that the same way in the digital world, which is kinda nice. But the higher ISO numbers are gonna be more sensitive. So you can make photos with less light. Which can be handy. Of course, th...
ere is a flip-side to everything in life. The trade-off is that you do get some digital noise with that. But these days, you have to be shooting at the highest ISO ever to see noise anymore. It has come such a long way. I remember the early days of digital photography, and high ISOs of like 800 would be like sandpaper. (laughs) When you looked at the, I mean it was really bad. It was so bad. And now it's quite amazing. So you can get away with a lot these days. So let's talk a little bit more about this. So ISO settings are like the film settings, the film speed. So 100, 200, 400, and in between, there's also numbers in between. But we'll just make this nice little example here. With clean, easy whole numbers. 'Kay so the lower numbers are less sensitive, the higher numbers are more sensitive. What you're doing in the digital camera when you crank up the ISO, is you're amplifying the signal that is coming in on the sensor. So if you jack it up really high, it's really getting amplified. So it's more sensitive. That can result in more noise, but sometimes, who cares? And sometimes the more noise is not even discernible. So, that can be very handy in low light situations. So where do we find this setting on our camera? Well, on some cameras there's a button. Like here, there's a button that's labeled ISO. So, I press that and then I turn the dial on the back, and that's gonna control my ISO. And it shows me there, on my display, where it is. On other cameras, you may have to get into your functions, get into your menus somewhere. It might not be quite as convenient, to change your ISO. So you may have to dig a little bit. Again, check with your manual if you can't find it. But it's in there somewhere I promise. Okay. You'll also, you might find I guess, on some cameras there's also a setting for ISO called auto. So you may bump into that, so you may have like 800, 200, 100, something called low, and something called auto, so you might find that. Some cameras also have something that they just call high. And you're like, what is that? I don't know. It might just jump from 400, 1600, and then it might just say high. How high is high? I don't know, you'd have to read the technical specs to figure out what's really happening. And some cameras put governors on this, so it won't go past a certain point unless you unlock it in the settings somewhere in your menu. So you might bump into that. ISO can be kind of funny from camera to camera. But just so you know, that is how it works, that's a little bit about where you can find it, and what it does. Now it does not have a creative effect on your image. In other words, when we talk about this exposure triangle, and these three factors that make up our exposures, ISO doesn't do anything like give you blurs, it doesn't give you nice yummy blurred backgrounds or motion blurs. It doesn't do that. What it does do is it enables other things to happen. It enables you to maybe use the slower or faster shutter speed that you need to get. Or it might enable you to get away with maybe your maximum aperture is only like 3.5 or something, and you're in a somewhat dark environment without getting flash mixed in, you don't have a whole lot of options. But you could jack up your ISO, and then maybe whatever available light is there could work for you. If you could just boost your ISO, 'kay. So that is how that all comes together. Well, that is the basics of exposure, okay? So you just really want to keep in mind, that there is no right answer, that the combination of these three combination of things can come together in any kind of way. So we could all be in one scene, we could be shooting it together, and we could all take a picture, all of our photos could look great, and we could look at the exposure data, which by the way, is embedded into all the files. We'll talk about that. And they could all be completely different. So keep that in mind. There's not a wrong answer. Where do you find this data in your images? Well, you can always see it when you play back the image on your camera, when you hit the playback, you'll see it. And usually there's an info button somewhere around the back of your camera, and if you press it, it'll show your shutter speed, your aperture, your ISO, your file name, what your white balance was, it might show you a histogram, it'll show you all kinds of information. That information stays with your photo even after the fact when you download it onto your computer, you can see all of that data on your computer as well. Which is really great because when you're learning about photography, and you take a photo and then you get it on your computer later and you look at it, and you think this did not turn out how I wanted, or why is this blurry? Or why is this whatever. Then you can look in your metadata and you'll see oh, I shot that at one 30th of a second, really? And then it's like, no wonder it's blurred because I didn't have a tripod or something. Right so, you can really learn a lot and trouble-shoot your own mistakes by going back through your exposure data.