This article is going to get into some specifics on exposure and how you might set up your camera to get the best exposure in certain situations. I will do that by presenting some exposure scenarios you are likely to encounter and show you how I would handle them. My hope is that it ties together all the articles on exposure and really gets you comfortable with this subject.
But first, lets make sure you are up to speed on the different aspects of exposure. I have articles posted on every aspect of proper exposure, and if you haven’t seen them, you might want to review them prior to diving into this article. After making sure you are up to speed, we can move on to the exposure scenarios.
Prior Articles on Exposure
I have two articles on the concept of exposure in general and how it works on the camera. First, I have an article on the concept of exposure in general that shows you how your camera works. Second, I have an article applies those concepts to your camera that shows you how to manipulate the 3 exposure controls of shutter speed, aperture, and ISO.
Beyond that, there are articles on each of the 3 exposure controls that you might want to check them out. They are:
- Shutter Speed: this article addresses the nuts and bolts of shutter speed, and also shows you some creative uses. Speaking of creative uses, you might also want to check out this article for DPS on some creative uses of shutter speed.
- Aperture: the second article covers the effect of aperture sizes on exposure and depth of field. In addition, you might check out this article for an explanation of the specifics of aperture measurements (and stops in general).
- ISO: finally the third article explains the concept of ISO. You might also want to check out this article for an easy strategy for using and changing ISO.
Again, I am just pointing you to these articles to show you some of the ways exposure has been covered here, so you can review any areas you are not already comfortable with. In this article, there will not be a lot of explanation about these concepts, just showing you them in action.
With all that out of the way, now I want to do something different. In this article, I will walk you through some real-life scenarios you are bound to face, and show you how you might think about exposure in those contexts. We can put these concepts into action.
So come along and let’s go through a few scenarios. It will be like a virtual field trip.
Keep in mind as you go through these scenarios that there is no real “right” answer. Reasonable minds can differ. Further, you may be trying to do something different that would require different settings. So I’m not trying to tell you what to do – just show you how I would think about it. With that said, let’s dig in.
Scenario 1: Sunset
Here’s the first scenario. You are out with your camera and there is a beautiful sunset you want to capture. It is just you, your camera, and your wide-angle lens (no tripod). The sun is over the horizon so it is just starting to get dark. Your camera settings read:
- Shutter speed: 1/30th of a second
- Aperture: f/8
- ISO: 200
You have a beautiful shot composed and your focal length is set at 24 mm. The problem is that your cameras meter says you are 1 stop underexposed. You take a test shot and confirm that is the case. How should you adjust?
When you have the answer thought through, read on.
Exposure of Scenario 1
You know the only three ways to add the light are to increase (lengthen) shutter speed, make your aperture wider, or increase ISO. The question is which one you should change. The answer, I think, is to move your ISO from 200 to 400. To see why, let’s look at the 3 controls in order:
- Shutter Speed: Your shutter speed is at 1/30. You are nearing the danger zone for “camera shake” with this slow of a shutter speed. If you add a stop of light by increasing (lengthening) your shutter speed, that puts it at 1/15 of a second. Recall that a stop of light is a doubling of light, and in the context of shutter speed that means you would double the time. 1/15 of a second is really slow, and you could have a problem with camera shake, even if you have image stabilization in your camera or lens. In fact, the Reciprocal Rule says that with a focal length of 24 mm our shutter speed should be no slower than 1/24 of a second. So we will not want to lengthen our shutter speed to add the needed stop of light.
- Aperture: Your aperture is f/8, which is a good moderate shutter speed. It will probably work for you just fine unless you are trying to capture a subject immediately in front of you and also leave the background sharp as well. But if you increase the size of your aperture by 1 stop, that means increasing it to f/5.6. That is a wide aperture that will result in a narrow depth of field. Is that what you want for a landscape photo such as this? Probably not. I would avoid adding light by increasing the aperture in this context.
- ISO: Finally we have ISO, currently set at 200. An ISO of 200 presents no problem for almost any camera. Increasing it one-stop would put it to ISO 400. That presents no problem for most modern digital cameras. Therefore I would add the light by increasing my ISO by one stop, from ISO 200 to ISO 400.
Scenario 2: Wildlife/Bird
You are out with your camera and notice a bird you want to photograph. It is not too far away from you, so the lens you have on your camera, which is an f/2.8 lens and extends to 200 mm, will almost fill the frame with the bird. You look through your viewfinder and the scene is correctly exposed with the following settings:
- Shutter speed: 1/60th of a second
- Aperture: f/11
- ISO: 200
Since the camera is set up to at the proper exposure level, you want to keep the same exposure level as you have now. However, these settings are not ideal for a wildlife shot such as this. How could your improve your exposure settings for this shot while maintaining the current exposure level?
After you have considered this issue and have your answer, read on.
Exposure of Scenario 2
When you are photographing wildlife, including birds, a shallow depth of field is just fine. In fact, it is generally preferable. You want the creature you are photographing to be tack sharp, but a blurry background is generally nice. A sharp background would actually detract from the subject.
Recall that a shallow depth of field is obtained by using a large aperture (and remember that a large aperture is one with smaller numbers). The settings above have an aperture of f/11, which is a fairly small aperture that will get you a moderate to deep depth of field. You don’t want that. You want a larger aperture to blur out the background.
I would open up the aperture all the way. The lens in this scenario opens up to f/2.8. That is a 4-stop difference from the current aperture setting of f/11. Starting at f/11 and going down by 1 stop, you get f/8; then gong down the second stops gets you to f/5.6,; then f/4 after the 3rd stop, and finally to f/2.8 after moving 4 stops.
The good news is that making the aperture larger lets in more light as well. So you just added 4 stops of light to the picture. But if you take the picture without making an offsetting change, it will be very overexposed. You can offset the change either by using a faster shutter speed or decreasing your ISO.
In this case, I would apply all 4 stops of light to the shutter speed and make it as fast as possible. Recalling that each stop of light doubles our shutter speed, the shutter speed would be 1/120 after increasing it by 1 stop, then 1/250 after 2 stops, then 1/500 after 3 stops, and finally 1/1000 after moving 4 stops. So the final settings would be a shutter speed of 1/1000, aperture of f/2.8, ISO 200.
You could use one of those stops to reduce your ISO from 200 to 100, but I wouldn’t bother. Shooting with an ISO of 200 rarely results in any significant noise. Plus I think you should keep the shutter speed as fast as possible.
The faster shutter speed will help make sure that this is a sharp picture. The initial shutter speed of 1/60th of a second is too slow and risks some camera shake in your picture. The Reciprocal Rule says that when you are shooting with a focal length of 200 mm, your shutter speed ought to be at least 1/200. I would stress the “at least” part of that prior statement, especially when shooting wildlife, and even more so when photographing something that moves as fast as a bird. Getting the shutter speed to 1/1000 will help ensure that you stop the action.
Scenario 3: Child on Playground
You are at the park and your child is playing. You want to take a few pictures of them at play. You are using your favorite DSLR with a 50 mm f/1.8 lens. You look through your viewfinder and the camera’s meter says the shot is properly exposed. You look at the exposure settings and they are:
- Shutter speed: 1/60th of a second
- Aperture: f/11
- ISO: 200
How can your exposure settings be improved? Once you have your answer, read on.
Exposure of Scenario 3
This scenario has a lot of similarities to the wildlife scenario above.
You already have enough light for the shot, so that is nice. I would take some of that light away from the aperture and apply it to the shutter speed. By that I mean I would open up the aperture all the way, which would allow more light into the camera, and offset that change by increasing the shutter speed.
Recall again that increasing your aperture, while it lets more light into your camera, has the trade-off of decreasing your depth of field. Except that here it isn’t a trade-off at all. Just as with the wildlife picture, you actually want the reduced depth of field. The sharp subject and the blurred background is the best look for this sort of shot.
In this case, because you are using a 50 mm prime lens, you can actually open up the aperture wider than you could in the wildlife shot. The 50 mm opens up to f/1.8, which is a full stop wider than the f/2.8 lens used in the last scenario. Since you are currently at f/11, you could open this lens up by 5 stops. Counting out 5 stops is as follows:
- Stop 1: f/11 to f/8
- Stop 2: f/8 to f/5.6
- Stop 3: f/5.6 to f/4
- Stop 4: f/4 to f/2.8
- Stop 5: f/2.8 to f/1.8
I think, in this case, I would actually only open up the lens to f/2.8. There are a few reasons for that. First of all, you have plenty of light coming into the lens at that aperture setting. That will already result in a nice shallow depth of field. Further, I don’t think you want to risk having the depth of field too shallow. You want the whole subject to be sharp, and if you open up all the way to f/1.8, you are running the risk of introducing blur not just to your background, but to portions of your subject as well.
There is one other reason for keeping the aperture at f/1.8. Most lenses have an aperture setting that is a sort of “sweet spot,” where the lens is at its sharpest. That spot is usually a stop or two down from the lens’s widest setting. So by sticking with f/2.8, as opposed to opening it all the way to f/1.8, you are keeping the lens at a place where it is likely to be at its sharpest.
You now need to apply all this extra light that you introduced by opening up the aperture to either the shutter speed or the ISO. You really don’t need that fast of a shutter speed here, so go ahead and knock the ISO down 1 stop. That moves the ISO from 200 to 100, which in most cameras is its lowest native setting.
After that, you can apply the other 3 stops of light to the shutter speed. That will make your shutter speed 3 stops faster. You start at 1/60. Adding one stop of light doubles the shutter speed, so it is now 1/120. Adding another stop doubles it to 1/250. Adding the third stop of light doubles that to 1/500.
Therefore, the final settings I would use are a shutter speed of 1/500, aperture of f/2.8, and ISO 100.
Scenario 4: Daylight Photo with Neutral Density Filter
This one will be a little different. Let’s say you are out photographing a coastline (or beside a lake or river). You have your camera on a tripod and you have a shot lined up with a focal length of 28 mm. You have your camera set up to take a proper exposure. The settings are:
- Shutter speed: 1/60th of a second
- Aperture: f/16
- ISO: 100
Everything is fine, except that now you want to take a shot with a 10-stop neutral density filter to blur the water. You add the filter to your camera, and now you have to change your settings to compensate. What are the best settings to use to go about doing that?
Exposure of Scenario 4
When you have water in your picture, a really slow shutter speed often makes the picture look exponentially better. However, the slow shutter speeds necessary for this effect are not possible during daylight. The amount of light your let into your camera by holding the shutter open that long would overexpose the picture. So the way to add this effect when there is too much light is to add a neutral density filter. This filter restricts the amount of light that is allowed in your camera, but otherwise does not affect the image. These filters come in various strengths, but a particularly handy one – and the one we will use in this scenario – is a 10-stop neutral density filter.
After adding the filter, the camera, which was previously properly exposed, is now 10 stops underexposed. You have to find 10 stops of light and add it to the camera.
Before we talk about what you should do to add the light, let’s start with what you don’t want to do. First, you don’t want to open up the aperture if you can help it. This is a seascape and you want a wide depth of field. Second, you don’t want to increase the ISO if you can help it. As usual, you want to avoid digital noise in your picture. You can make small adjustments if you need to, but you want to keep from making any drastic changes to either of these settings.
That leaves shutter speed. Of course, the whole point of putting the neutral density filter on the camera was to slow down the shutter speed, so you will want to do that. This is possible because you have a tripod in this scenario, so holding the camera steady is not an issue. You can make the shutter speed as slow as you want.
Adding 10 stops of light to your starting point of 1/60 puts the shutter speed at 15 seconds. Here is how it works:
- Original: 1/60
- +1 Stop: 1/30
- +2 Stops: 1/15
- +3 Stops: 1/8
- +4 Stops: 1/4
- +5 Stops: 1/2
- +6 Stops: 1 second
- +7 Stops: 2 seconds
- +8 Stops: 4 seconds
- +9 Stops: 8 seconds
- +10 Stops: 15 seconds
A 15 second exposure will completely blur the water. If that is what you want, you are done. If, however, you only want the water partially blurred, you will need to shorten the shutter speed a bit. Do that by slightly increasing the aperture and ISO and then shortening the shutter speed by a corresponding amount.
Scenario 5: Sunset again, but this time you have a tripod
This scenario is a repeat of Scenario 1, with one important change: this time you have a tripod.
The settings on the camera in this scenario are:
- Shutter speed: 1/30th of a second
- Aperture: f/8
- ISO: 200
You have a nice sunset picture lined up using a 24 mm focal length. There is nothing moving in the picture. The problem is that you are 1 stop underexposed. In addition, you want to make sure you are using the best possible settings for this scenario. What should the shutter speed, aperture, and ISO settings be in this scenario?
Exposure of Scenario 5
The answer last time was to increase the ISO by 1 stop, from 200 to 400. This time the answer is quite different.
Because you have a tripod and there is nothing moving in the picture, there is no reason you cannot use a slow shutter speed. Camera shake is no longer a factor. Movement of any kind is no longer a factor. You can therefore use a slower shutter speed to fix all your problems.
The first problem, of course, is that the picture is 1 stop underexposed. So you can easily fix that by slowing down the shutter speed by 1 stop. Changing the 1/30 shutter speed by 1 stop gets you a new shutter speed of 1/15. Exposure problem solved.
But what about the other settings? Are they ideal? Probably not, so let’s change them now.
To start with, the depth of field that will result from an aperture of f/8 is a little shallow. Since this is an outdoor, landscape-type shot, you want a wide depth of field. You could probably live with f/8 if you had to (and, as set forth in Scenario 1, I would live with it if I was hand-holding the camera). But here, since you have a tripod, there is no reason to live with f/8. Stop down the aperture to something like f/16. Doing that costs 2 stops of light (from f/8 to f/11 is 1 stop, from f/11 to f/16 is the second stop).
Since you have closed the aperture by 2 stops, the shot will be 2 stops underexposed if you don’t change something else. As mentioned above, there is no reason not to slow down the shutter speed to fix any exposure issues in this case. So just slow down the shutter speed by another two stops to offset the change in aperture. Slowing down your shutter speed of 1/15 by 2 stops gets you to 1/4 (going from 1/15 to 1/8 is 1 stop; then from 1/8 to 1/4 is the second stop). Making that change puts your exposure level back to even.
The last setting is ISO. Ordinarily, an ISO of 200 is just fine. But here, again, since you can change shutter speeds all you want without consequence, you might as well make the ISO exactly what you want. And what you should want is the camera’s lowest native ISO, which will usually be 100. That will get you the absolutely cleanest picture, devoid of digital noise. So go ahead and change your ISO from 200 to 100, which is a 1 stop change.
You will need to offset that change you just make to your ISO or your shot will be 1 stop underexposed. So go back to your shutter speed control and lengthen the shutter speed by one stop. The shutter speed is currently at 1/4, so moving it by 1 stop puts it at 1/2.
With that change, you are finished. You are left with settings of 1/2, f/16, ISO 100, which are nice. You will have a wide depth of field. You will have the lowest possible ISO. The shutter speed is irrelevant since the camera is on a tripod and there will be no movement. The picture should turn out fine.
. . . and Now a Bunch of Qualifiers
I have presented all the changes as the “right” way to do things. Of course, there really isn’t a right way. It changes from person to person and scene to scene. These are just the way I would go about exposing these scenes. I presented my way as “the” way because I didn’t want to insert a bunch of qualifiers within the discussion. So if you found yourself disagreeing with me as you read this article, that is just fine.
In addition, keep in mind that these exposure decisions were made with me in a chair thinking about exposure. At the time of capture, you are often in the field with a fast moving scene. The light is changing, the subject is changing, and other conditions are changing. You have to move fast. You will not have the time to give exposure a careful study. Don’t worry about that. Frankly, that is the reason you should think about it now, while you are in front of a computer, so that it is natural when you have the camera to your face.
Final Thoughts on these Exposure Scenarios
The goal here is to show you exactly how the concepts of exposure that have been addressed in prior articles apply to your photography. In other words, we are moving from the theoretical to the practical. Hopefully, this helps you and on the way to mastering exposure.
To make this even more concrete, I also have a video that works through exposure in a few different scenarios. Check it out.