In this video I want to talk for a few minutes about getting a correct exposure. Now let's back up just a second and make sure we know what we're talking about when we're talking about an exposure. An exposure is basically taking a picture and the... that you're using to take that picture so that it looks the way you want.
And that's what a correct exposure is, a picture that you've taken that looks the way you want. So it doesn't necessarily have to look the same as what your eyes are seeing for it. to be correct to you.
But in this case, we are going to use that as an example. Based on what my eyes are seeing, I'm going to set an exposure of a scene and just kind of walk you through the options you have to change to create a correct exposure and things to watch out for as you do that. So let's just real quick.
I'm in scene intelligent auto. I'm on the green A. We're just going to stay here for just a second.
I'm going to press the live view button and And here is the scene we're looking at. We have some flowers. And for those of you who have watched my other videos, you know right now I'm sitting under this big skylight.
It's an overcast day, so I have nice diffuse light coming in. This jar of flowers is at the edge of that skylight. And beyond that, it starts to get pretty shadowy fairly quickly. You can see there's a ruler and there's something white back there.
We're going to be able to see those things in a moment. But here's what the camera judges to be a correct exposure of this image. And it's pretty close.
But, you know, the camera doesn't always decide what's best. And in this case, to talk about all of our options that we have to change, I want to switch to manual. And so that's what I'm going to do now.
I'm going to rotate the dial to M. And you should follow along. Feel free to follow along. I think this is going to be worth a lot more worth your time if you have your camera in hand. And it doesn't matter if you have a Canon T4i or a Nikon.
The general settings that we are talking about are identical for all of these cameras. So here I am in manual mode and very nicely across the top now I have the three options that I want to talk about when you're setting an exposure. Your first is your shutter speed. That is the length of time that your shutter remains open when you take a picture. Right now it is set on 1 500th of a second because last time I was taking pictures that's what I had it set on and it remembers that and it keeps that there until you change it.
Next I have aperture. I'm just going to press Q and highlight that. Aperture is the opening, the size of the opening of the lens.
It's expressed in a fraction. We're not going to go in detail to talk about that right now, but I'll just say that the smaller the number, the larger your opening. Lenses generally go from somewhere around, depending on how much you pay, 1.2, 1.4, all the way up to 22, 36 in that general range.
The f1.4, f2, f2.8, those are very large openings, almost as wide as the lens glass itself. On the other end of the spectrum, the f22, f22, f36, those are tiny, tiny openings, just barely large enough for you to insert a pin through. That's your range. f5.6 is, you know, kind of a medium open, again, expressed in fractions. And finally, your final option here is...
is your ISO, the sensitivity of the sensor. Now I know that's not great. It's not very explanatory since I'm saying two words and trying to use both of those in the same definition, but the, the larger the number, the more sensitive that sensor is, that little piece of electronic equipment in your camera to the light coming in. And it's a fact, it's a doubling factor. So at ISO, at ISO 200. it as twice as sensitive as it is at ISO 100. At 400, it's twice as sensitive as it is as 200. I'm going to stop stuttering over my words there and let's just go back to our main screen.
So let's press live view now and it's showing us, this is one of the reasons why I really think live view is a great learning tool, I've said that in other videos, it's showing us the exposure we would get with these current settings. The shutter speed across the bottom, five hundredths of a second, our aperture 5.0 and our ISO of 400. If we half press the shutter you can see that the camera helpfully says this is where I think your exposure is relative to a correct one. Correct one should be right there in the middle. What the camera thinks is a correct one. And again, remember what the camera thinks is a correct one and what you want as a correct one are not always the same.
Often they're very similar when you're just trying to take regular pictures, but they're not always the same. And I don't know if you noticed, but it did move a little bit based on the amount of light coming in through the skylight, whether or not it's brightening the scene or... darkening the scene. So let's start to adjust our values of these settings to get a more correct exposure. First thing I'm going to do, the shutter speed is already selected.
1 500th of a second is pretty fast. I can go a lot slower than that before I run into any kind of negative effects. Do you know what those negative effects might be?
Did anybody out there say motion blur? Now that is correct. In this situation, the camera is sitting still. It's taking a picture of very still life.
Nothing is moving. So you could go to shutter speeds very, very slow, multiple seconds, and there wouldn't necessarily be any negative impact on your image. And that would still give you a correct exposure.
Let's do that just for fun. Let's go all the way down and take a picture one second long. I dialed it says 1 now my image of course is really overexposed.
I'm going to go to 100 that makes the sensor as less sensitive as possible and now by holding down the AV button I can dial the aperture. way up and notice 22 is the maximum for this lens and the camera is now saying that I am overexposing slightly from what it believes to be a correct image but this is actually very close to the image that I want to create here and I'm going to go ahead ahead and press the shutter button. It's going to take a picture. It took one second to take that picture. Let's go and put that on the screen for a second and get rid of all of the info, but you can see one second F22 ISO 100. And there's my image and everything is fine.
We should be able to zoom in on those flowers and they are a little bit brighter than I would like, but everything is crisp and the image is just fine. We should also notice that the plant in the background, although dark, is in focus. We'll talk about that in just a second more.
Now That was the example of going there. But what if I was taking pictures, what if I was holding the camera, or if I was taking pictures of people moving? Well, those are two different things. So let's say first, if I was holding the camera and taking a picture of this flower, the one thing that you want to watch out for is for is shutter speeds slow enough that you won't be able to hold the camera steady during them. If I picked up this camera and held it for one second the image would be very very blurry.
The general rule of thumb is that your shutter speed should be a bit higher than your focal length. Right now I'm shooting with a 35 millimeter lens. My shutter speed should always be above 35. The one time that you can break that rule and you're holding the camera is when you have a lens that has IS.
Then you can go a little bit slower. But now let's say you're taking pictures of something that's moving. Somebody that's moving. Your kid, toddler, a dog running in the backyard. Now you're talking about shutter speeds that you want to be able to see.
up around 125th of a second. That's a pretty good safe shutter speed for movement, unless we're talking about things that are moving very fast, or you could go a little slower if things are moving a little bit slower. In this case, you can see that my image is now very, very dark.
So what I'm going to do is I'm going to roll my aperture, increase my aperture a good bit. I'll go to 2.8, pretty close. And now I can increase my ISO. ISO sensitivity to 400 and those flowers in the foreground are a little bit brighter than I want. I'm going to go back down to 200 for ISO and now you can see that my exposure is identical, virtually identical, and you can see that little exposure meter at the bottom, virtually identical to the exposure I shot a minute ago that was a one second in f22.
But But notice there are other differences now. Well, let me go ahead and take this picture. And press playback.
Here it is. So exposure-wise, brightness, it is very, very similar. However, that plant in the background now is very soft and not in focus because I was shooting at such a smaller aperture. aperture so aperture increases and decreases the size of your lens opening and that allows in various amounts of light depending on the size of the opening but it also impacts your depth of field how in focus things are so you How I approach each situation is I say, well, what kind of aperture do I want for this? And I set it accordingly.
Then I figure out the shutter speed I need and set that accordingly. And then if I need to adjust my ISO to get the shutter speed where I want it to be, then I'll do that. So that's usually my approach. Start with the aperture.
And an easy way to do this is... to shoot on AV mode. You set your aperture where you want, the camera will set the shutter speed, and you still have to set your ISO based on. You could also go to Auto ISO if you want. I'm not a big fan of Auto ISO.
It makes, this is again letting the camera have a little bit more control. And the more control you let the camera have, the more likely it is going to be to make a bad decision. It's kind of a bummer.
We do have these really expensive, really nice cameras. But they, they're just not as smart as us. After a little bit of learning and understanding.
how these different settings affect our image quality. So this was just a really quick, simple look at changing those values, talking a little bit about exposure. I'm going to come back with more videos that talk in-depth. I'd like to have a series of kind of recipes, but really it all depends on what you see and the factors of fast enough to avoid motion blur, fast enough to avoid handshake, the aperture... that you want for the scene, whether or not you want to kind of separate somebody from the background or it's a vista and you want to get all of it in focus, then you're going to be shooting at those really high numbers, which is a really small opening.
And then the ISO. And the one thing you want to watch out for your ISO with your kind of entry-level DSLRs is still around ISO 1600. Above that, we start to get quite noisy. And so if you can keep below that number, and the lower the better, usually.
then you're going to have a better a cleaner image but if you need to go higher to keep that shutter speed from getting blurry or getting long enough that your image is blurry then you're going to want to do that because a slightly noisy non-blurry photo is better than a blurry photo that's not noisy unless you're going for artsy blurry so i hope this was helpful if you have any questions about it leave a comment down below or find me over on the facebook page i do appreciate you watching. As I said, more videos of this sort coming soon, and I do try to keep them as short as possible, but we're covering topics that are fairly weighty, and I want to give them the time that they deserve. Thanks for watching.