Knowing Your Shutter Speed

So by now we’ve really established how your camera creates photos – by exposing light onto your sensor – and that your shutter speed controls how long your image is exposed for. However, your shutter can do a lot more than just gauge the right exposure for you – it can drastically change the content of your image. The goal is to know how the shutter speed affects your images and what situations to apply it to. That is what this section is all about – mastering your shutter speed and how to use it for landscapes.

Freezing Action With Your Shutter

You’ve probably noticed that with some photos you’ve seen, the action seems to be literally frozen in time – such as water being thrown from a bottle, or a speeding train flying by.

We can’t really see this with our naked eye as it happens too fast, but a fast shutter speed can capture this movement so that we can take our time looking at it.
Image copyright morozena.

When images like these are captured, you’re literally freezing the action with a fast shutter speed – usually at least 1/2000ths of a second…but it really depends on how fast your subject is moving.

To visualize this, think of a rainstorm and how fast the droplets can fall from the sky. Usually we can’t see them actually in the sky as they fall, but rather when they hit the ground and splash. However, like in the image below, a fast shutter speed can freeze the drops as they fall, offering a visual that is rarely seen.

In this image of a spider web, I used a very wide lens (f/1.8) so that I could achieve a fast enough shutter speed to capture the raindrops as they fall (1/4000ths of a second). This wide aperture also explains the beautiful bokeh and depth of field.

Action can happen so fast that we can’t actually see what’s happened until it’s already over. Photos like these let us look at a split-second moment (or rather, up to 1/8000ths of a second) in great detail, which is why fast shutter speeds are so popular in action photography (sports specifically).

If you think of why cameras are used for “photo finishes” during a race, this concept makes much more sense. Our brains can’t register who hit the finish line first when it’s a matter of inches between the contestants, so we rely on a camera using a very fast shutter speed to show us. If a slow shutter speed was used, the motion would be blurred thus rendering the image useless in determining who won the race.

Like aperture, you can set your SLR camera to allow you to adjust your shutter speed to the setting you want, while still letting the camera change the aperture for you to allow different amounts of light in for proper exposure. This is called shutter priority mode, and is essentially a reverse of aperture priority mode.

When choosing a shutter speed for your images – landscapes in particular – ask yourself if anything is moving in your photo, and how you want to capture that movement. Usually we’re not dealing with fast-moving objects with landscapes, but you may want to freeze rain, snow, or a waterfall.

There are also many long exposure tricks that benefit landscapes, which I will describe step-by-step how to do in a future article. For now, I’ll just introduce the topic briefly.

Slowing Down the Movement for Landscapes

More often than not, you’ll see a need to use a slow shutter speed rather than a fast one with landscapes in order to capture the image you want. A slow shutter speed will allow you to create a surreal smooth effect with clouds, water, or other moving objects, like in the examples below.

This photo had a shutter speed of 400 seconds, which allowed for the water to become glass-smooth, ,and the slow-moving clouds to appear dream like and painterly. This long exposure also picked up on some surreal sky colors that would not have registered if I took this photo with a normal shutter speed.

A long exposure was needed in order to capture this harvest moon and the trees in the foreground (8 seconds). If I decided to just expose this photo as the camera saw fit, then I would have a detailed image of the moon but none of that great foreground tree action. The longer exposure allowed for more light to be captured than what the camera recommended.

When you take a photograph with a slow shutter speed (usually one 1/30th of a second or less depending on the lens you’re using), you’re exposing your image for a longer time than what your eyes can normally register. This sort of works in the opposite sense of when you use a fast shutter speed (freezing action that we cannot see with the naked eye).

With a slower speed, you’re extending the exposure time, capturing what our eyes can’t see because they work too fast. Like in the images above – you’re basically compiling hundreds of images that you would normally see separately with your eyes over the span of 400 seconds (or whatever your extended shutter speed is) on top of one another in order to create a long exposure photograph.

I’ll discuss long exposure photography for landscapes in a more detailed separate post, but for now I just want you to know that it’s fun and a beautiful art form of landscape photography.

How to Avoid Blurry Photos

If you’ve ever taken a photo in low-light conditions that comes out blurry or just unusable, it’s most likely caused by what we call camera shake. In short, camera shake is caused by extended shutter speeds when the camera is handheld – you’re literally exposing your image so long that the minor movements you make with your camera just by holding it can cause the exposure to blur since you’re repositioning the camera during exposure. If your camera moves during a long exposure, it can’t capture your image sharply.

Tripods are the instant fix to this since it sets your camera to a fixed point, making sure that any shaking caused by the camera being handheld is now obsolete.

How do you figure out if your exposure is too long to be exposed without camera shake? There has to be a limit somewhere since photos taken with plenty of light don’t suffer from this. Where is the line on shutter speeds that can’t be crossed over without a tripod?

Yes, there is a minimum shutter speed that you should not go under if you wish to have a photo without blur caused by camera shake. However, this will change depending on the lens you use since longer focal lengths will require a faster – or higher – shutter speed. There is a scientific explanation for this if you like to know the exact reason, but for now just know that your minimum shutter speed will be related to your focal length.

The most popular rule of thumb in calculating your minimum shutter speed is 1/your maximum shutter speed.

So, for example, if you have a 50mm prime lens (one without zoom), your minimum shutter speed will be 1/50th of a second.

If you have a 18-180mm lens, your minimum shutter speed will be 1/180th of a second. However, no such shutter speed exists, so you will need to round up to 1/200th of a second.

As I said, this is the most popular rule. However, recent experiments have concluded that a new rule should be followed to ensure that your images are as sharp as they can be, and free of blur. Instead of 1/the maximum focal length of your lens, you should double your minimum shutter speed to be twice the maximum focal length.

So if you’re still using the 50mm prime lens, don’t shoot anything under 1/100th of a second if you want to be absolutely sure that you won’t have any camera shake in your image.

While you could probably get away with using 1/50th of a second most of the time with your 50mm lens, it’s always better to play it safe if you want a sharp image. Also, since you’re shooting digital, you can check your images to see if you have a sharp enough photo before continuing.

If your lens has image stabilization capabilities, make sure to turn it on when you have the camera handheld (if you have your camera on a tripod, turn this feature off as it can actually be detrimental to your image when stabilized on a tripod – long story). This feature will help the camera stabilize your image if you cannot get a fast enough shutter speed to eliminate camera shake – usually, you are safe for a sharp image up to a few stops below your minimum shutter speed calculation.

NOTE: A “full stop” in photography means adjusting either your f/stop or shutter speed one setting in either direction. So if your minimum shutter speed is 1/100th of a second, then you’re probably safe to shoot at 1/60th of second (two settings slower) with image stabilization turned on.

How to Get a Faster/Slower Shutter Speed

If you’re in a low light situation where you’re finding it difficult to increase your shutter speed by available light alone, there are several things you can do with your manual settings to increase your shutter speed.

As you learned in the previous lesson on aperture, the wider you open up your lens, the more light is let in – thus a faster shutter speed. You can use the side effect of adjusting your aperture to your advantage if you’re looking to get a faster shutter. So the next time you find yourself with a need to increase your shutter speed, look to your aperture for a boost.

Alternatively, you can use your aperture to slow down your shutter speed if you want to take a longer exposure to blur water, clouds, or other moving objects in your landscape.

For example, if you’re taking a photo at f/8 with a shutter speed of 1/30th of a second, you can increase your aperture to f/16 which will automatically decrease your shutter to 1/20th of a second (when shooting in aperture priority mode).

There are side effects to using your aperture that you should be aware of. Since you’re adjusting your f/stop, you’re also changing your depth of field. So if you’re looking to a long exposure with a wide aperture during the daytime, you’re going to have far too much light to be able to execute this.

Thankfully, you can purchase filters for long exposure photography that can decrease the amount of light that is let into your lens (think of these filters as being similar to a pair of sunglasses). I’ll talk more about filters in that future post on extended exposures I keep talking about.

So to recap briefly here:

The shutter can not only control how much light is let into your sensor, it can cast wonderful effects on moving subjects in your image. Whether you want to freeze action or slow it down, your shutter can create scenes not visible to the naked eye.

Your shutter can also cause you some unwanted complications if you don’t know what you’re doing. Camera shake can blur your images when you don’t have enough of light to handhold your camera, so a tripod is often needed to take sharp images. For landscape photographers, we generally use a small aperture and can shoot in low light conditions (the twilight hours), so a tripod is definitely necessary.

You can also do things like adjust your aperture in order to achieve the shutter speed you want if available light (either too much or too little) is causing problems for you.

To add further functionality to your shutter speed, you can also adjust your ISO setting. Your ISO is to digital as film speed is to analog photography (Kodak 400 film for example). In the next section I’ll talk more about your ISO and how you can use that to adjust your shutter speed, and also some potential drawbacks when doing so.