I've started a short series on the three major things you need to know if you are wanting to branch away from using the Auto settings on your DSLR: aperture, shutter speed, & ISO. Some of this may initially sound intimidating, but trust me, once it all clicks (pun intended) your photos will start turning out the way you envisioned them. No more guesswork.
Today, I'm focusing on shutter speed. (Yay, two puns in a row!) I've already talked about aperture/f-stop in this article, so go catch up in case you missed it!
how shutter speed works
Shutter speed is the speed at which your shutter opens & closes & is measured in seconds. The shutter opens when you press the shutter button down, &, depending on your settings, will stay open however long you told it to. 1/100th of a second. 1/10th of a second. 30 seconds.
The key with shutter speed is knowing this: the faster the shutter speed, more action will be stopped. 1/1000 will stop WAY more motion than 1/10. Also, less light will enter your lens with faster shutter speeds.
Going from 1/500 to 1/250 is considered one "stop", just like with the aperture where going from f/2.8 to f/4 is one "stop." Slowing down your shutter speed by one stop will essentially double the amount of light entering your camera. If you have a correctly exposed photo, but you decide to increase your shutter speed one stop, decrease your aperture by one stop to compensate. Shutter speed & aperture are inversely related.
Motion blur is blurriness in your photo due to action like a train speeding by or a person running. Stopping a lot of action, like someone running, requires a much fast shutter speed than for subjects sitting still.
One thing to consider is which direction is the subject moving? If the subject is running laterally to the camera, you will need a faster shutter speed than if that same subject is running towards the camera at the same speed. Even though the subject is running at the same speed, the camera only sees a fraction of the movement. (Think legs & arms flying through the air.)
Sometimes you may want to keep motion blur. If you want to showcase the arch of the bouquet as it flies through the air, streaks of rain, the path of a river, taillights of cars on the highway, or spinning wheels on a bicycle, choose slower shutter speeds. In most of those cases you will want to use a tripod, however.
If you are just starting out, you probably want to avoid shooting anything slower than 1/60 handheld. Anything slower than that should be shot with a tripod, or with the camera propped up on something. Even if your subject is not moving, your image might still come out blurry due to camera shake, which is not the same as motion blur. Camera shake is usually caused by something like shaky hands, strong gusts of wind, or trying to hold a very heavy camera while focusing on something really far away.
Zoom lenses intensify camera shake, so if you're in the market for a new telephoto lens, consider buying one with Image Stabilization (IS) that helps reduce camera shake.
More tips coming later on how to help reduce camera shake.
depth of field
Say you are looking down a row of apples lined up & you want to focus on only the middle apple while blurring out the apples in front & behind it, choose a fast shutter speed. Basically, this only gives your camera enough time to focus on the one apple. The longer your shutter stays open, the more time the camera has to focus on the other apples. Couple a fast shutter speed with a wide open aperture & you will get a photo with very little in focus. I'll dive more deeply into this subject in a later post!
Stay tuned to learn about the mysterious ISO settings!