Courtesy photo
An example of a small aperture. Approximately f/32.

Once upon a time, I used to be a shutterbug.

In fact, I actually went to school to study photography. I wanted to be the next Ansel Adams or the Nick Brandt of America.

But like a lot of artistic people, “real life” — otherwise known as bills, jobs and the like — encroached on my time, and I allowed it to do so.

Now, after more than half a decade away, I intend to return to my roots. However, I have found the adage “use it or lose it” is pretty apt.

So, I thought that as I was re-teaching myself, I could help others who wish they knew more about controlling their DSLRs, as well.

In my first three columns, I am going to discuss the three basic pillars of exposure — aperture, ISO and shutter speed.

Aperture

In the simplest terms, aperture is the size of the hole that light travels through before it hits the camera’s sensors or, if you’re old school, your camera’s film.

It’s modeled off a human eye and acts a lot like the pupil, widening to allow more light and narrowing to cut down the amount of light being allowed in.

Or, put another way, the bigger the hole is, the more light that is allowed in to burn the image.

You can widen the aperture in low-light situations, allowing the maximum amount of light in for the best exposure possible in that situation.

It is important to note that aperture, ISO and shutter speed all affect each other, which I will go into more detail on in a later column.

Aperture is a function of the lens, not the camera, even though aperture generally is controlled through dials on a DSLR.

F-stops

Lenses are identified by their F number — or the size of the aperture, when wide open — and aperture is measured in what is called f-stops.

F-stops can appear complicated because there are decimal points involved that don’t seem to make any sense.

This basically is because the formula used by the lens has to do with πr², the calculation of the area of a circle using its radius (r).

Simply put, f-stops are measured either through the halving or doubling of light received by the camera’s sensor.

When it comes to actually using the camera, the important thing to know is the smaller the f-stop, the bigger the opening.

Depth of field

Another thing important to note is that aperture affects the depth of field (DOF), and depth of field is critical when it comes to photography.

DOF the distance between the nearest and the furthest objects that give an image judged to be in focus in a camera.

In other words, it is the amount of the image that appears in focus from front to back. If the DOF is small, then the background (and foreground) will be blurry.

And of course, the opposite also is true — if you have a large DOF, then your image will be sharp from front to back, up to the amount the lens will allow.

The way aperture affects DOF is pretty simple — the larger the aperture, the smaller the depth of field.

Other factors also can affect the DOF, including placement of the camera in relation to the subject and how much or little the lens is zoomed in.

But the basics remain the same — if you want a portrait with a blurry background, move closer to your subject, zoom in and use a wide aperture, such as f/2.8, f/5.6, f/7.1, etc. If you want a landscape — or cityscapes — zoom out, set a low shutter speed, get a tripod and use a narrow aperture (f/16, f/18, f/20, f/32, etc.).

Until next time, happy shooting!

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