Friday, March 16, 2012

Photography 101 | Aperture

Just joining in? Here is what you've missed:
Photography 101 | Coming Soon!

Welcome to my Photography 101 series!  I am so happy that you have decided to join me to learn how to use your DSLR camera in manual mode.

Before we get started I want to mention a few things.  These posts are intended to help you learn how to use your camera in manual mode, using natural light in the environment you are shooting in, meaning that you are not using the flash on your camera.  I will be writing these posts assuming that you have a basic knowledge of how your camera works, how to properly hold it, focus it, etc.  However, if you aren't sure about something, ASK!  I'm happy to answer questions, so please do not hesitate to contact me if you need help.

My intent for this series is to help beginning photographers learn to use their cameras in manual mode.  In order to do that, I think it is important to understand the function of each of the settings, and how they interact together to create a photograph.  So, I will do my best to provide simple explanations and examples along the way to help you understand the concepts.  In an attempt to prevent your eyes from glazing over, I'm going to try to avoid getting too technical or using too much complicated terminology.  However, if you desire a more in depth explanation of something, feel free to contact me and I will be happy to provide more information.

Let's get started, shall we?

I would like to begin by asking you to do a little experiment. Please take a flashlight and a mirror with you into a dimly lit room. Look into the mirror, aim the flashlight at your face, and watch what happens to your pupils as you turn the flashlight on and off. You should notice that when you turn the light on, your pupil gets smaller, and when you turn the light off, your pupil gets larger. Why? Because in order to see properly, we need a certain amount of light inside of our eyes. Too much or too little makes it hard for us to see.  So, we have a built in regulator to adjust the amount of light that gets into our eyes.

Applying this same idea to photography, we need a certain amount of light to enter the camera to create a photograph.  One of the ways that we can regulate the amount of light entering the camera is by adjusting the aperture of the camera.  The aperture of a camera is simply an opening that allows light to pass through it.  If the aperture is made larger, more light will enter the camera.  If the aperture is made smaller, less light will enter the camera.

To demonstrate this, I took a series of photographs of a single subject.  All of these images were taken with my EF-S 18-55mm IS Zoom Lens, with my shutter speed set to 200 and my ISO set to 200.  (I chose this lens because it is the stock lens that came with my camera, and is probably similar to the lens that most of you are using. There are no particular reasons why I picked these shutter speed and ISO settings other than they would work well for this demonstration.  For now, don't worry about these settings.  I will cover each of them in coming posts.)  For each consecutive photo, I then changed my aperture setting by one stop to show the effect on the image.  The first shot was taken with an aperture of f/5.6 and the last image was taken with an aperture of f/29 (The reason I picked this range of aperture openings is because it is the range that this particular lens will allow.  Each lens is different, so your largest and smallest openings will probably be different than mine.)

OK, now for the complicated part, so please hang in there with me!  The hardest thing to understand about aperture is how the setting adjustments are named, and how to move properly between them.

Aperture is measured in "f-stops" and the common f-stops are f/1, f/1.2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, and f/32.  By adjusting between two consecutive settings you either double, or cut in half, the amount of light that you allow to enter your camera, depending on if you make the aperture larger or smaller. (Many lenses offer a wider range of options than the list of standard ones that I give here. In those instances, the amount of light difference between settings varies by a different amount.)

You may hear someone mention "stepping up or stepping down" the aperture, or they might say "stopping up or stopping down" the aperture.  Stepping (or stopping) up is referring to raising the f-stop by one step (i.e. f/8 to f/11), which decreases the aperture opening by half and decreases the amount of light entering the camera by half.  Stepping (or stopping) down is referring to lowering the f-stop by one step (i.e. f/8 to f/5.6), which doubles the aperture opening and doubles the amount of light entering the camera.

The thing you have to keep in mind is that these measurements are FRACTIONS.  Yep, we're digging deep here to remember elementary school math, my friends!   So, if you think back you may remember that 1/2 of something is a much larger portion of it than 1/32 of it. The same thing is true for your camera's aperture setting. A setting of f/2 is much larger (resulting in much more light entering the camera) than f/32 (resulting in much less light entering the camera). So, as you adjust the settings, you must remember this little fact to make sure you are making adjustments in the proper direction!

If you look at the above series of photos, you can see that the first photo was taken with the aperture set at the largest setting of f/5.6 and allows enough light to enter the camera to show the image. The last photo was taken with the aperture set at the smallest setting of f/29 and doesn't allow much light to enter, resulting in a photo that is much too dark.

I encourage you to experiment with your camera's aperture setting this week and become familiar with the available settings for your lens(es), and how changing it affects your images. To do this, set your camera on manual mode, and set your shutter speed to 200 and your ISO setting to 200. (Again, there is no particular reason for these numbers. They are basically just "middle of the road" settings that should work for this experiment.) Then take a series of images like the ones I took above, changing the aperture setting by one stop between each exposure. I suggest taking a series of photos for several different subjects in different environments to see what results you get.

Then join me back here next Friday and get ready to learn all about shutter speed!

Michele Whitacre is a portrait photographer serving Phoenix, Arizona and the surrounding area. Visit Michele's website at Become a fan of Michele's work on Facebook. Follow Michele's updates on Twitter.

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