I know a lot of photographers already know what aperture and shutter speed is, and readily know how to use it, but this article is meant for the photographer that is just starting out or just purchased their new SLR or dSLR camera and want to know how it works, or just needs to brush up on the basics.

Aperture

In simplest terms aperture is how your camera’s lens controls the amount of light going through itself. Inside your lens there are a series of about six to seven overlapping blades that close or open to constrict or allow as much light entering the lens as you would like, this device is called the iris or diaphragm.

The amount of light that enters the camera changes as you change your camera’s “f-stop value”, which is the description of how much light is entering the camera at any given time. Different camera lenses have different f-stop ranges. The lower the f-stop value (f/1.5) means a greater diameter for your lenses iris which lets more light enter your camera, as a result your picture will be brighter. The higher the f-stop value (f/22) means a smaller diameter for your lenses iris which lets less light enter your camera; as a result you have a darker picture.

When you close down your lens one f-stop at a time (moving from f/1.5 to f/22), each step lets in half the amount of light as before. Conversely if you open your lens one f-stop at a time (moving from f/22 to f/1.5), each step lets in twice the amount of light as before. So for example if you moved from f/5.6 to f/8 then your going to let in half as much light and if your going from f/8 to f/5.6 your going to let in twice as much light.

There are different effects, besides having a lighter or darker picture, when deciding on an f-stop value to take your picture with. With the smallest f-stop value (like f/1.5) you get a smaller depth of field. This effect is very good for isolating your subject by blurring your background. With the largest f-stop value (like f/22) you get the largest depth of field, it is the most that in is focus from nearest to farthest. This effect is good for landscapes and any other shot where you’d like your entire picture in focus. Varying your f-stop value you get different depths of fields.

That is the main functions of aperture and depth of field.

Shutter Speed

Shutter speed is how your camera controls the amount of time your film or digital sensor is exposed to light by regulating how long, in seconds, your camera’s shutter is open. The iris talked about earlier in the article is a type of shutter. The exposure of your picture is directly proportional to the amount of time your digital sensor of film is exposed to light.

Slow shutter speeds (1 second) result in having a longer amount of time that light is allowed to enter your camera. When you are using slower shutter speeds you will want to use a tripod so reduce the amount of blurriness in your picture due to camera shake. Slow shutter speeds are typically used for night photography or having different effects of blurriness to show movement or motion.

Fast shutter speeds (1/1000 second) result in the having a shorter amount of time that light is allowed to enter your camera. Fast shutter speeds are typically used for shooting clean, sharp, photographs. Fast shutter speeds are used to capture objects in motion, to freeze them in their actions.

Just like aperture, as you go through shutter speed “stops” the light entering the camera doubles or becomes half as great. As you go from 1/4 of a second to 1/2 of a second your letting in twice as much light. As you go from 1/2 of a second to 1/4 of a second your letting in half as much light.

A rule of thumb for different shutter speeds and lenses is that the slowest shutter speed used easily without much blur from camera shake is the shutter speed numerically closest to the lenses focal length or smaller. For example if you are shooting with your lens at a focal length of 30mm you should use a shutter speed of 1/30 of a second or less to ensure less blurry photographs.

Relationship Between Aperture and Shutter Speed

Shutter speed and aperture go hand in hand when shooting pictures in photography. A fast shutter speed (1/1000 second) requires more light, a smaller f-stop value (f/1.5), to get the best exposure. If you use a faster shutter speed and have a large f-stop value your picture will come out either too dark or completely black.

A slow shutter speed (1 s) requires a lot less light, a larger f-stop value (f22), to get the best exposure. If you use a slow shutter speed and have a smaller f-stop value your picture will come out either too bright or completely white.

I hope this article helped you better understand aperture, shutter speed, and how they work together inside your camera to create the images you love, now go get snapping!