Digital Cameras are amazing devices. They capture images in digital format, instead of on film as original cameras did. But once we get beyond how the images are captured (memory card or film), Digital SLRs work a lot like their film based cousins. What does that mean to you?
Just because you’ve got Nikon’s latest camera and a few thousand dollars in lenses, if you don’t know how to use your camera beyond the automatic mode, you’re not getting everything you can from your camera. In this series of articles we’re going to talk about some basic photography principles that not only apply to digital cameras, but also apply to film cameras as well. Exposure, composition, depth of field, shooting RAW…..we’re going to look into how to control all of this.
This article is an introduction, and we’re going to get a little technical. But when we’re finished you will have a basic understanding of how to get better exposures for your travel photos when you’re on the road, and you’re going to understand some of they mysteries of how you can control your camera, even on manual.
What Controls Your Exposure?
If we’re talking strictly about landscapes and interesting scenes from your travels, and not about working portraits into your routine (yet), then there are 3 things to consider that affect your exposure. This is the technical stuff, but we’re going to simplify it for you in this article. So, what are the 3 things?
Aperture, Shutter Speed, & ISO are the three things that control the exposure. Now in the film days when we were shooting there were 3 primary items that controlled your exposures. Aperture, Shutter Speed, & Film Speed (what is now ISO). Bottom line? In the transition from film to digital, nothing has changed about how you control your exposure.
Let’s say you have a shiny new camera and you just want to start firing away. You set it to fully automatic mode, allowing the camera to make decisions about the scene in front of you. Here’s what the camera does. It evaluates the scene and will choose what it believes to be the correct Aperture, Shutter Speed, and on some cameras, even the ISO. You’re letting the programming decide for you, and sometimes our digital devices don’t see the world the way we do. Learning about controlling the exposure yourself will help you create (an important factor) a scene the way you actually see it!
So, let’s talk about each item. We’re going to explain the basics of each part that impacts your exposure separately, and then we’ll bring them together. When we’re done talking about this, if you didn’t know much about Film SLRs, you will when we’re finished.
Aperture controls how wide open your camera’s lens is. You can have a very wide open Aperture or a very narrow one, depending on the effects you’d like to create. And the apertures that you can use depend on the lens you have. Some lenses can go super wide (1.4 for instance), where others start out a little narrower (5.6 for instance). Lenses that offer a very large aperture are always more expensive, and they’re referred to as a “fast” lens. We’ll explain a little more about that later.
There are a whole range of Apertures, from super wide open to extremely narrow. The wider the lens opening is, the more light gets into your recording medium (be it a digital sensor or a piece of film). The narrower the lens opening is, the less light hits your sensor. So, let’s say you take the same photo with a wide opening, and then again with a narrow opening. In order to keep everything else the same we’re going to use manual mode so nothing else impacts the image.
As you can see, Aperture directly effects your exposure if you change nothing else. I kept the camera set at ISO 200, shot for 1/2500th of a second, and only varied the aperture. This is straight out of the camera, nothing edited or changed.
Aperture is a little weird when you think about it. Not what it does, but how it’s labeled. F1.4 is super wide, F22 is super narrow. You’d think it would be opposite, but it’s not. Just something you have to remember. Low numbers are wide, high numbers are narrow.
So, why would you vary your aperture? I mean, why not just shoot wide open all the time? What would cause a person to want to shoot at F22? There are plenty of reasons to vary Aperture, and we’ll talk about them later.
You now have the basic idea of how aperture works. So we’re going to talk about shutter speed next. As you saw above we kept the same shutter speed for our 3 examples. This time around we’re going to do a similar example, and we’re going to vary our shutter speed while keeping the other two exposure factors constant.
As you can see in the 3 examples, we kept our aperture at f4 for all shots, and we kept our ISO at 200. What changed in each image was how long we allowed the shutter to stay open. 1/200th of a second (very fast), 1/40th of a second, and one whole second.
The longer we leave the shutter open, the more light gets into our sensor (or film). The shorter the length of time for the shutter, the less light gets in. Notice in the first image with a short time (only 1/200th of a second) the inside of the Airstream is dark, but out the window looks beautiful. The really long exposure shows the detail in the Airstream, but out the window we can see nothing as it was so bright out there.
Why vary your shutter speed? Why would we want to do a super fast exposure vs a long exposure? Here’s one for you….. Photographing a bicycle race. If you do a long exposure of a cyclist riding by they will be a blur while the rest of the scene stays constant. If you do a super short exposure, maybe 1/2500th of a second, you may just freeze that cyclist in your frame. Depending on what you’re shooting, you’ll want to vary the length of time you’re exposing. We’ll cover that in greater detail below.
In the days when film reigned supreme you might have noticed there were different film speeds. 100, 200, 400, 800…..do you remember that, or am I just getting old?
The different film speeds were there for a reason. 100 was a slow speed film, 800 was fast. The numbers were used to tell you the light sensitivity of the film. 100 wasn’t super sensitive. It was good for well lit scenes like a landscape. 800 was very sensitive, and was used for shooting higher speed photos. ISO works the same way.
ISO 100 isn’t very light sensitive. ISO 6400 is super sensitive and you could shoot in a dark room! There is a tradeoff though when using a higher ISO. Noise.
If you remember the film days, higher speed films (like 800) allowed you to shoot at faster shutter speeds. People would use the film for photographing sports, birds in motion, etc. But the images were always grainy if you looked close. The higher the film speed or ISO is, the more noise gets introduced to your image. But with today’s digital sensors, even shooting at high ISO can produce some amazing images. Let’s show 3 more examples.
As you can see, varying only the ISO (light sensitivity of the sensor) we can stay at an aperture of f/4, and a shutter speed of 1/200th of a second and get some very different results. The interior of the Airstream is unlit and a little dark. So, photographing in a dark room with no flash at ISO 200 doesn’t get me there. But bumping the ISO up to 6400 makes my sensor very light sensitive and we’re able to get a decent exposure.
As you can see, changing your aperture, shutter speed, or ISO, can impact your final exposure. Using all 3 to create the exposures you want opens up so many creative possibilities. Shooting mountain bike races? High shutter speed alone will make for dark images, but if you use a wider aperture and higher ISO you’ll get the right exposure. Want to photograph the Milky Way? High ISO, wide aperture, and about 30 seconds of keeping your shutter open.
So, now what? Let’s talk about putting all of these things together, and what we’re trying to achieve.
Pulling it all together!
On the more advance cameras, Digital SLRs, the new mirror-less cameras, you might notice a bunch of options available to you. You’ve got your full auto, Tv, Av, M, maybe even a B. What are they all about? Well, auto is auto. P is programmable mode (not professional mode), Tv is shutter priority, Av is aperture priority, M is manual (scary) and in the case of my 5D Mark II, B is bulb mode.
For my landscape work I always work in Aperture Priority Mode. Why do I do that? The aperture not only controls my exposure, but also my depth of field. If my aperture is wide open I will not have a good depth of field. If I narrow my aperture I will get a deeper depth of field for my landscapes. When in aperture priority mode I set the aperture and my camera sets the shutter speed for me. Normally I like to run f/5.6 to f/8 for a good depth of field. I let the camera figure out how long the exposure should be (the shutter speed) to achieve what I want. If the shutter speed is too slow for lets say a handheld image I might bump my ISO up. Take a look at the examples below.
Do you notice how in focus the grill is, but the background isn’t in focus at all? I shot this at F/2.5 to had a very narrow depth of field. I wanted to blur the background and have only some of the image in focus. If I’m trying to show a large landscape, this probably won’t play well.
Changing to F/14 for an aperture made a huge difference. See how much more in focus the background is? The shutter speed was slower for this one, 1/10th of a second.
At F/22 the camera selected a shutter speed of 1/4 of a second. A very long exposure indeed, and something you couldn’t shoot hand held. All 3 images were shot on a tripod. The longer my shutter stayed open, the more detail I got in the background in this case.
This of course is an extreme example. My normal setup for landscapes finds me at ISO 200, F/5.6 to F/8 in Aperture Priority Mode and I let the camera select the shutter speed. Anything longer than 1/60th of a second isn’t good for a handheld photo, my hands could shake. So if the shutter speed is longer than that I’ll just up my ISO. See how we’re combining the three elements here?
Examples of when to do what
So, when are we messing with Aperture, Shutter Speed, & ISO? What causes us to make one choice or the other if we’re working on our travel images? Here are a few examples of what I do.
- Shooting landscapes: Normally when I shoot landscape I work in Aperture Priority Mode (Av). I’m usually set between f/5.6 and f/8. I’m shooting at ISO 200 and I let the camera figure out the shutter speed. If I’m focused on a big scene in front of me f/8 should have a good depth of field and get everything in focus well.
- Shooting flowers: Still in Aperture Priority mode. Now however I like a narrow depth of field. So I’ll shoot at f/1.4 or 2.5. If it’s daylight I’m still at ISO 200 and I still let the camera decide shutter speed.
- Shooting a mountain bike race: Here’s where things change. Most likely I’m going to bump up my ISO if in a darker area, pick a wider aperture (f/4 for my 200mm lens), and set my shutter speed to something fast. I’m going full manual here as I want to control everything. A few test shots will be in order before the racers show up.
- Shooting the Milky Way: We’ve got a whole tutorial on this site about night photography and editing afterward. But quickly, let’s talk about this. To get the Milky Way with no star trails it will need to be a fast image. I open my aperture to f/4, set my ISO to 3200 or 6400, and use a cable release to control the length of my exposure (Bulb mode on my camera).
Every situation is different. But knowing how aperture, shutter speed, and ISO work you can now work on how to combine them to get your best exposure in most any circumstance! Keep in mind, if you’re holding your camera and not using a tripod you want to make sure that the shutter speed is faster than 1/60th of a second. If you have to, bump your ISO instead of changing your aperture when doing a landscape! Better yet, bring a tripod. 🙂
In the next installment of this series we’ll get deeper into controlling your exposure and composing your scenes. We’ll also talk about depth of field a little more in-depth. After that, we’ll talk about why shooting in RAW can help you control your creativity with your shots.
Also, don’t forget that we’ve got another video series on using Lightroom while on the road. And an updated one for Lightroom 6 will be coming soon as well!