Shutter Speed and You

Now that you've practically mastered ISO and Aperture, we'll turn our attention to shutter speed - the last remaining setting in what some photogs call the "Triangle of Exposure." Your shutter speed is just that – the amount of time that your shutter is open. This is measured in seconds and can also be set manually by you or automatically by the camera, according to how long the shutter needs to be open in order to let in the necessary amount of light for a correct exposure.

Related terms and phrases: long or short exposures, seconds, exposure time

You'll find your shutter speed is adjusted with the small dial found by your shutter button when in Tv or Manual mode. (Some cameras offer a "bulb" mode which keeps the shutter open for customizable amounts of time.) The shutter of your DSLR is similar to your car engine in that it has a life span. Amateur and mid-range cameras have an approximate lifespan of about 50,000 shutter clicks while higher end professional grade DSLR's approximate 100,000 images.

The shutter speed is measured in seconds – most often the shutter is open for a fraction of a second. Only the denominator is displayed in your viewfinder. Long shutter speeds of whole seconds are displayed with second marks (4”). The larger the denominator (numbers again, hang in there), the faster the shutter speed. That means the shutter is open for a very short amount of time (i.e. 1/500 of a second), and therefore ample light is needed in order to make a correct exposure (that's where your aperture training comes in!).

If you're looking to capture a city skyline at night, you'll need to use a longer shutter speed (smaller denominator or even whole seconds). Keep in mind that the longer your shutter is open, the more important it is that your camera keep still. Most people recommend using a tripod when shooting 1/60s or slower. Image stabilization is being added to an increasing amount of lenses, allowing the user to shoot with a slower shutter speed and receive less camera shake. A rule of thumb regarding focal length and shutter speed: it's a good idea to keep the denominator of your s.s. larger than the focal length of your lens. (Shooting with a 200mm lens, keep shutter speed at least 1/250s. Lens with a fixed 50mm focal length should use at least 1/60s s.s.)

As with aperture, shutter speeds double in amount:

1/500s, 1/250s, 1/125s, 1/60s, 1/30s, 1/15s

The smaller the denominator number, the longer the shutter is open and the more light is allowed in. Adjusting your speed from 1/500s to 1/250s will double the amount of light exposing the film/hitting the sensor.

So what can shutter speed do for you? It all depends on what kind of movement you want to capture in your image. You have the power to freeze all movement, or to capture an image full of movement and blur.  A faster shutter speed freezes the movement; a slower shutter speed allows the movement to blur.

The images below were taken with a slow shutter speed. The shutter was open for 1/5s during the exposure and I followed the moving subject so that it was clear and the background became blurred. Had I remained still, the car would become the blurred motion.

F/29 at 1/5s

When your subject is stationary, you can also achieve motion blur by using a slow shutter speed as in the photo below.

F/22 at .3s

Because the shutter is open for an extended period of time, the aperture is quite small. The time of the exposure lets in enough light for the aperture to remain narrow. Need to freeze the movement? Then make sure your aperture is wide enough to let in enough light for correct exposure over a very brief amount of time.

These photos were taken last summer during a family vacation. My four younger cousins are water sport masters as evidenced by the mad air they're getting. I felt successful when I remained attached to my board...

Images 1&2 : F/4.5 at 1/2000s     Image 3 : F/4.5 at 1/2500s

So to bring it all together – ISO, Aperture and Shutter Speed are three adjustable elements that work together to create a correctly exposed image. Remember that you have the most control over these elements when shooting in Manual mode.  A few things to keep in mind:

A change in aperture or shutter speed requires a change in the other. Opening your aperture a bit wider? This will let in more light, allowing the shutter to be open for a shorter amount of time. Increasing one will allow you to decrease the other to make a correct exposure. (For example, if a correct exposure is a result of F/2.2 at 1/800s, a correct exposure will also result from F/1.4 at 1/1600. More light is allowed in with the second combination, so a quicker shutter speed is acceptable.)

Shooting in low light? Keep in mind that you can always increase your ISO, but watch out for that grain. Other low light options include opening your aperture wider to let in more light or increasing the length of time the shutter is open.

I suggest visiting this site if you want to learn more.

Upcoming LGP EDU : Lighting, Composition, Working with People....

Friends, meet Aperture.

Welcome to installment two of LGP EDU -- Thank you for coming back! I'm going to jump right into this one so we don't waste any time; aperture is a doozie. The truth is, if you want consistently good photos, aperture, ISO and shutter speed need to become your good friends. So let us begin this beautiful friendship.

There are endless forums and websites that will offer you a far more extensive and technical (i.e. mathematical equations), explanations of your camera's aperture and shutter speed but I'm going to approach it as if these are brand new concepts and will try to portray them in a less intimidating light. The best way to master these concepts is to sit down with your camera and experiment. This will allow you to see the immediate effects of the changes that you make to either setting. Today we'll meet  Aperture.

In lay-terms, Aperture refers to the size of the opening in your lens; the opening is controlled by a diaphragm which is either set by you (manually), or by your camera (auto), according to the amount of light that is needed for a correct exposure. Basically, it controls the amount of light that is allowed in to expose the film (or, digitally, contact the image sensor).

Related terms and phrases: F-stop, minimum and maximum aperture, lens speed, low light settings, depth of field, wide, narrow, large, small.

Your DSLR has an Av Mode - this allows the user to set the aperture and then the camera takes care of the shutter speed. Change the Aperture (or f-stop), using the small dial usually found by the shutter button when in Av. (Again, I prefer and suggest the Manual Mode which gives the user greater control of the final exposure as you have the ability to set both the aperture and the shutter speed. On most DSLR's you'll set the aperture using the Av button.) Under and over-exposed images are often a result of the Auto or Program mode - the camera's built in light meter often reads the background of the image and fixes the settings appropriately. This can result in too much or not enough light directed on your subject.

So what's with all the numbers? I'm so glad you asked. Each number is referred to as a stop. One stop either doubles or halves the amount of light. If you go from f2.8 to f2, you have doubled the amount of light exposing the film/sensor. (Most cameras offer quarter and half stops, too.) Here is a scale of the standardized aperture stops and a visual to acquaint you with the different sizes of lens openings:

f/1.4 – f/2 – f/2.8 –f/4 – f/5.6 – f/8 – f/11 – f/16

Low light situations call for wider apertures. The smaller the number, the wider the lens opening, the larger the aperture = more light. Example:

F/1.2 at 1/25s

Ben in Times Square at evening - low light situation called for a wide aperture.

While a wide aperture lets in the most amount of light, a narrow aperture lets in less light. (You've seen those photos in which the sun looks like a little star burst? This is the result of a narrow or small aperture.)

F/11 at 1/80s

Had I used the program mode here, the Brooklyn Bridge would only be a silhouette.

The most commonly used lenses (kit lenses), can range from f3.5-22. Professional grade lenses are a bit faster as they are intended for lower light situations (wedding ceremonies, receptions, events, etc.), and often open as wide as f1.2, making them quite a bit pricier. How do you know the widest aperture of your lens? It is listed within the name of your lens on the lens barrel with the "f" in front of the number: Canon EF 35-80mm f4-5.6. Note that a zoom lens will have two f-stops; f4 is the widest aperture available when shooting at 35mm; f5.6 is the widest aperture available when shooting with the lens zoomed out to 80mm.

Aperture also affects your depth of field, or the portion of your photo that appears sharp and crisp. A wide aperture results in a clear subject matter surrounded by a blurred background (this is an example of shallow depth of field). This is ideal for portraits and product shots as the background becomes blurry, not fighting for the attention that should be given to the subject. Landscape photos are often taken with a smaller aperture. The photos below illustrate a shallow and an extended depth of field.

F/ 2.0                                                                               F/7

See the difference? The larger aperture creates a more shallow depth of field, drawing the eye to the red cook book, while the smaller aperture allows the viewer to see every title. Assuming that most of us are visual learners, few more examples:

Both images f/1.2 and 1/125s

Detail shots are often much more visually interesting when a wide aperture is used. A smaller or narrow aperture is often preferred when shooting landscapes; this provides the image with an extended depth of field.

F/14 at 1/400s.

Of course, aperture works in cahoots with ISO and shutter speed; well wrap up the techie convo with shutter speed next time and take a look at how the three interact. Please feel free to leave a comment, question or helpful link below to add to the discussion!

If you'd like to continue reading about Aperture, I suggest you go here.

aperture illustration borrowed from www.seanmorlin.com/blog - thanks!