Now that we have a solid grasp on aperture, no really go read that first, unless you’re already a master, let’s talk about it’s counterpart, shutter speed.
This one is a little bit more straight forward than aperture. Shutter speed is simply how long the shutter is open to allow light to come through the lens onto the sensor. Shutter speed is extremely important in photography, when you want a nice crisp shot of a car speeding by you or a beautiful shot of the milky way shutter speed will make or break the shot.
The standard for shutter speed is 2:1. Starting at 1 second the following stops are as follows: 1/2s, 1/4s, 1/8s, 1/15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s, 1/1000s, 1/2000s. Most modern DSLR cameras also have faster and slower built in speeds than that. Some cameras will go as fast as 1/8000 while others top out at 1/2000. Most of them will have slower speeds in the same 2:1 increments all the way down to 30 seconds. Some cameras also have a bulb mode which allows you to open the shutter for as long as you hold down the button. This is typically used with a remote trigger to reduce camera vibrations.
The general rule for shutter speed is that you need a shutter speed of at least 1/focal length of the lens to render a sharp image while hand holding the camera, this of course goes for non moving subjects. For example if you are shooting a scene with a 200mm lens and do not have a tripod, to be safe make sure you have a shutter speed of at least 1/200 to get a sharp image. If the subject is moving this varies dramatically. The faster the object is moving across the frame plays a huge role in image sharpness in this situation. If you are shooting a car that is far away it won’t be moving much relative to the frame, however if the car is extremely close it will be moving extremely fast relative to the frame. The faster it is moving relative to the frame the faster the shutter speed required to stop the motion.
In the images below you can see this effect taking place. As I increased the shutter speed, the cars become less blurry until eventually the moving cars are stopped in motion.
If you do not have enough light to achieve a 1/focal length shutter speed then you will need a tripod to keep the image from being blurry. If you have a moving subject and do not have enough light to freeze the subject a tripod will not help you. In this situation you’ll have to resort to other methods of getting more light on your subject. Such as using artificial light or increasing the ISO.
As with all things in photography the best way to learn is to take your camera out and experiment, have fun and as always, have a great day!