What is Aperture?
Understanding Aperture and Your Digital Camera

What is aperture? If you're shopping for a camera or even trying to get to know your DSLR camera better you've probably heard the term.

Aperture refers to the size of the opening in your lens. Like your pupil the opening in your lens can open and close to let more or less light in. If it's open wide it lets in more light. If it's closed to a small diameter it lets in less light.

Aperture is measured by what's referred to as f-stops or f-numbers. They are written like this: f/22, f/5.6, f/3.5, etc. The larger the f-stop the smaller the aperture or opening in the lens. For example, if set at f/22 the opening in your lens is smaller than if it were set at f/4. That may seem a bit confusing now. I know I found it to be confusing at first, but once you get used to it you'll have no problem remembering.

Obviously, the opening in your lense determines how much light gets in through your lens to your sensor. If the opening is large a lot of light gets in and if it is smaller little light gets in. In low light situations it's advantageous to set your camera at a low f-stop. In brighter situations you can have it set at a higher f-stop.

Besides the amount of light that gets into your camera there is another aspect to discuss when we answer the question, What is aperture? The wider open your lens is or the smaller your f-stop, the smaller your depth of field will be in your picture. This means that objects farther away in the photo will be out of focus. You can notice this most readily in macro photography, but it is also quite useful for giving the viewer a focal point in portraits and still life photography The smaller your lens is closed or the larger the f-stop number the wider your depth of field. This means that even objects in the distance will be in focus. This is useful when taking interior pictures like you would in real estate photography or landscapes.

• large f-stop = large depth of field
• small f-stop = small depth of field

Here are some pictures I just took to demonstrate this point.

This Photo was taken at f/36

This one was taken at f/13. Notice that the leaves in the background are a bit out of focus

This picture was taken at f/5.6. Notice that the leaves in the background are even more out of focus than the photo above.

Understanding the answer to the question What is aperture? will help you have more control over your camera and take photos that are more satifying to you creatively. THe only way to truely understand aperature is to experiment. So take your camera out of auto mode and start experimenting with aperture. When you get an image you like share with us in our share photos section.

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