It's Good To Be Shallow

Well, when it comes to photography, it can be.

Among the many aspects of taking a photo, your f-stop or aperture can be one of the most confusing.  In the simplest terms, the aperture controls how much light enters the camera.  The larger your aperture, the more light enters the camera.  The smaller it is, the less light it gets.  Simple enough, right?  Sure.  As long as you don't get deeper into it.  But we are.

The aperture size is represented by a number, or f-stop.  You'll hear numbers like f/2.8, f/3.5, f/11 and so forth.  But here's where things get confusing; the smaller the f-number, the larger your aperture will be, and the larger the f-number, the smaller the aperture will be.

This is an example of three aperture sizes.  At f/2 your aperture is wide open, allowing for a ton of light to enter the camera.  At f/22 the aperture is closed down and you have much less light coming into the camera.  What this means to you is that if your aperture is larger, since more light is coming in you can use a faster shutter speed.  If your aperture is smaller, then you're going to need to use a slower shutter speed to compensate for the lack of light.

Your aperture size will also determine your image's depth of field.  Simply put, "depth of field" refers to how wide (deep) or narrow (shallow) your focus is.  An image with a wide depth of field will have a clearer focus on objects further away from your subject, and a narrow depth of field will have less focus on anything further from your subject.  Take a look at the image bellow.  If you roll your mouse cursor over the different apertures below, you'll see exactly what all that means.

At f/1.4, your aperture is wide, wide open.  That means more light, and less depth of field.  So the trees and buildings behind the subject become very blurry.  At f/22, the aperture is smaller which equates to less light but far more depth - everything behind the subject is much clearer.  Knowing how aperture sizes affect your depth of field can really change the impact of your image.

As stated, at f/22 there is a lot more focus in the overall image which can create a background that is very busy, or visually confusing.  Your focus isn't necessarily drawn immediately to the subject - which you may or may not want depending on the feel you're looking to capture in your image.  With a shallower depth of field, the viewer's eyes are pulled right to your subject, but having your focus extremely narrow means parts of your subject could get blurred out as well.  Again, it all depends on what look you want for your final image.  Generally speaking, when taking portraits or product shots, having a shallow depth of field is recommended.