Knowing Your Shutter Speed

We’ve 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 by capturing motion in various ways. The goal here is to know how shutter speed can affect your image, and what situations you can apply it to. That is what this section will cover – how to master your shutter speed, and several creative ways that is can change your landscape.
 

Freezing Action With Your Shutter

You’ve probably noticed that in some photos, the action appears to be literally frozen in time – such as water being thrown from a glass, or an eagle swooping down to catch a fish from the river.

The image above shows falling raindrops, an example of movement that we can’t see with our naked eye as it happens too quickly. Fast shutter speeds allow us to freeze motion so we can analyze how subjects appear as they move. For this spider web photo, I used a very wide aperture (f/1.8) so that I could achieve a fast enough shutter speed to capture the raindrops as they fell (1/4000ths of a second). Using this wide of an aperture also explains the beautiful bokeh present and the shallow depth of field.

When images like these are captured, you’re literally freezing the action with a fast shutter speed – usually 1/2000ths of a second or faster. However, the exact shutter speed needed to freeze motion is entirely dependent on how fast your subject is moving – the faster the movement, the higher your shutter speed will need to be in order to capture motion without any blur.

To visualize this, think of a rainstorm and how fast the droplets fall from the sky – like in the sample image above. Usually, we can’t isolate them in the sky as they fall, but rather when they hit the ground and splash. However, a fast shutter speed can freeze the drops as they fall, offering a visual that is rarely seen without this assistance.

At times, the action can happen so quickly that we don’t realize what has happened until it’s over. By freezing movement, it lets us look at a split-second moment (or rather, up to 1/8000ths of a second for most cameras) in great detail, which is why fast shutter speeds are so popular in sports photography.

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 the results. 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.
 

 

The comparision images above show how differently your scene can look when shooting at different shutter speeds. When photographing the falling snow at 1/40, you can see that the flakes appear streaked and distracting as they move across my scene – not the result I wanted. As I increased my shutter speed, I also needed to widen my aperture to let in enough light to still expose my image properly. At 1/320, you can see that the snowflakes are now visible as they fall – the movement has been frozen.

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 like in the sample images above, you may want to freeze the movement of rain, snow, or water.

 

Slowing Down the Movement for Landscapes

For landscapes, you’ll more often than not find yourself using a slower shutter speed rather than a fast one in order to capture the image you want – especially if your intent is a deep depth of field. However, you can extend your shutter beyond simply what is needed to expose your scene correctly. By manipulating how much light enters your camera, you can prolong your shutter greatly, allowing 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 – eliminating all waves and currents. Additionally, the slow-moving clouds were captured in a surreal way, appearing dream-like and painterly. Not only is the content unique, but the colors from the extended shutter have blended together much like a watercolor painting. This combination of surreal sky colors would not have registered if I took this photo with a normal shutter speed.

 

When your available light is limited, you sometimes are forced to use a slow shutter speed to gather enough light for a usable image. A longer shutter speed 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 the foreground tree detail. The longer exposure allowed for more light to be captured than what the camera recommended, and applied a surreal sun-like effect to the moon.

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 – you’re encapsulating an extended piece of time and displaying all the movement that occured in one single frame. This works in the opposite sense of when you use a fast shutter speed – freezing action that we cannot see with the naked eye.

Here’s another way to think about long exposures – with a slower shutter 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), one on top of the another,  in order to create your long exposure photograph.

 

How to Avoid Blurry Photos

When shooting in low-light conditions, you may have experienced photos that appear blurry, out of focus, or just unusable. This is most likely caused by what we call “camera shake”. In short, camera shake is caused by slow 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 the camera is repositioning itself during exposure. If your camera moves during a long exposure, it can’t render your image sharply. Even the most minor and unnoticable movements in your camera can greatly affect image sharpness and quality.

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. What if you don’t have a tripod, or a tripod is not an option for the scene you’re shooting? Is there a rule of thumb to go by, a way to calculate the minimum shutter speed needed to capture tack-sharp photos?

 

Calculating the Minimum Shutter Speed

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 is directly related to your focal length.

The most popular rule of thumb in calculating your minimum shutter speed is 1/your maximum focal length for a full-frame (35mm) camera. For crop sensors (APS-C), your shutter speed will need to be a bit faster – 1.5 your maximum focal length.

For example, if you have a 50mm prime lens (one without zoom), your minimum shutter speed for sharp photos will be 1/50th of a second on a full-frame sensor, and 1/75th of a second for crop sensors.

If you have a 18-180mm zoom lens, your minimum shutter speed will be 1/180th of a second for a full-frame, and 1/270th of a second for a crop sensor.

However, you’ll often find that your exact calculations produce a shutter speed that does not exist, so you will need to round up to to the nearest option. For the lens example above, the mimimum shutter speed for a sharp photo would be 1/200th of a second on a full frame, and 1/320 for the crop sensor.

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 on a full-frame 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 on your LCD screen 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, you should turn this feature off as it can actually be detrimental to image sharpness when stabilized on a tripod – long story). This lens feature will help the camera stabilize your image if you cannot get a fast enough shutter speed to eliminate camera shake – depending on how fast you are moving your camera, you are usually safe for a sharp image up to a few stops below your minimum shutter speed calculation. This is a very handy tool that can save an otherwise unusable image.

NOTE: A “full stop” in photography means to double or half your shutter speed, depending on which direction you’re moving in. So if your minimum shutter speed is 1/100th of a second, then you’re probably safe to shoot at 1/25th of second (two stops 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 speed up your shutter. So the next time you find yourself with a need to increase your shutter speed, look to your aperture for a boost and shoot wide open.

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. By increasing your f/stop (making your aperture smaller), you’re restricting the amount of light let into your camera – so to compensate, your shutter speed will need to be longer.

For several reasons, it’s not wise to shoot with a very small aperture – usually above f/22 – as your image quality and clarity will start to drastically drop. If you’re interested in learning more about this phenomenon, you can click here for a detailed explanation.

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 1/8th 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 goal is a long exposure with a wide aperture (shallow depth of field) 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). These ND filters come in various strengths, and many photographers will “filter stack” by placing one filter on top of the other in order to achieve very long exposures under daylight.
 

Summary

So to recap briefly here:

The shutter can not only control how much light hits your sensor, but 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 how to compensate for them. 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 often shoot in low light conditions (the twilight and golden hours), so a tripod is definitely necessary.

You can also make changes to your manual settings – like adjust your aperture – in order to achieve the shutter speed you want if the 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 talk more about your ISO and how you can use that to adjust your shutter speed, and also some potential drawbacks when doing so.