"I Hate My Camera" - Understanding the Aperture

ISO 100, f/1.7, 1/500 sec. 50mm (75 mm equivalent)

Have you noticed how it makes you look smarter if you use a Latin word? The word aperture is Latin for an opening. Why not call the aperture a hole in your lens. You and I know what a hole is, but might not know what an aperture is (hey, I wasn't sure how to spell it for a while).

Understanding what the aperture DOES will open up a world of creativity for you. Are you excited yet?  You should be. Playing with different hole sizes, excuse me, aperture sizes will create different pictures.

But here’s the problem...understanding the language surrounding the aperture is like learning a foreign language. 

I know that you have questions about the aperture, so let's get started.

What exactly is the aperture?

The aperture is made of small plates in your cameras lens. These plates form a hole through which the light penetrates the lens into your camera. When the shutter releases this light is captured in the form of a picture on the camera's sensor. The size of the hole can vary to either let in more or less light.

What is the aperture like?

The aperture acts like the pupil of your eye. The pupil adjusts with the amount light. If there is too much light, the pupil shrinks so that you don’t go blind. If there is too little light the pupil widens to let in more light. The aperture functions in exactly the same way so that the sensor isn't bombarded with too much light and the picture ends up overexposed, or wanting for light and the picture's underexposed.

Are you still with me?

Everything I read about the aperture refers to the hole size with numbers like f/1.8 or f/16. What are these f-numbers?

This is the most difficult, yet critically important, aspect of understanding how your aperture works. Be prepared, you’re going to have to concentrate...sorry. There is no easy way to explain this, BUT DON’T STOP READING!

The “f” refers to “Focal Ratio.” (That’s for the geeks who need to know.) I expect you'll forget this tidbit by the time you finish reading this article. Take a deep breath. It isn't necessary to know this fact, however it does make a good Jeopardy question.

The number is CRITICAL for you to understand. CRITICAL, CRITICAL, CRITICAL!!! 

Now get this because it is going to make absolutely no sense. THE SMALLER THE “F” NUMBER THE LARGER THE HOLE. THE LARGER THE THE “F” NUMBER THE SMALLER THE HOLE. (This number is referred to as the "f-stop.")

Read that paragraph over and over again until you dream about it tonight. You don’t have to understand it, just KNOW it.

Okay, grab a cup of Joe or highly caffeinated soda before continuing. We’re now going to move to a creative possibility when experimenting with the aperture size.

REMINDER: The aperture is only one third of the photographic trinity. The other two parts of this trinity are the shutter and ISO. All THREE work together to help you create amazing photographs.

Why is it important to know the different aperture sizes?

Let’s take an indirect road to answer this question. Let’s go down the rabbit hole of DEPTH OF FIELD (DOF).

When you focus your camera it locks on a specific object in front you like a tree, but the tree is not the only thing in focus. Most of the time objects both in front and behind the tree are also in focus, but there is a gradual drop off into the blurry unknown both in front and behind the tree. It doesn't happen all at once, but little by little. An example of this is the picture at the top of the blog.

One of the influences on DOF is the the size of the aperture. I’m sure there are great articles out there that explain the why the aperture changes the DOF, but I’m going to focus on the WHAT...what happens with different aperture sizes.

Here is the general rule of thumb: The LARGER the aperture (f/1.8 for example) the SHALLOWER the DOF. The SMALLER the the aperture (f/16 for example) the DEEPER the DOF. It's all counter intuitive, BUT THAT’S HOW IT WORKS, OKAY? 

SIDE NOTE: There are two other major influences on DOF. One is the focal length of your lens. A wide angle lens creates a deeper DOF, a long lens creates a shallower DOF.  (Probably another blog post here). The other major influence on DOF is the size of your camera’s sensor. A full-frame sensor will create a shallower DOF than a cropped sensor. This is why point-and-shoots have a difficult time creating a shallow DOF. They have a tiny sensor. (Yah, another blog post here too.)

What is the best f-stop (aperture size) for tack sharp pictures?

Wow, that’s a great question. I’m glad that you asked.

People like looking at pictures that are tack sharp, super in focus. Believe it or not there are f-stops that are better at being really sharp than others. Some of this sharpness will depend on the lens itself. 

For the uber geeky person out there, you can determine the f-stops that are the best at creating a really clear photo by doing the following: Set you camera on a tripod outside in the shadow of your house on a sunny day. You want plenty of light but no shadows. Set up an object that has some texture to it, focus on the object and take pictures of it at all the f-stops of your lens.  Upload them to your computer, enlarge the pictures and examine their sharpness.Take note of these f-stops that are the sharpest.

For not so geeky people among us, most lens are at their sharpest between f/8 and f/10.  This is not to say that other aperture settings aren't sharp, but, hey, I’m just answering the question you asked. Don’t shoot me.

Because of a thing called DIFFRACTION I’d be careful using smaller (larger number) aperture settings than f/16. It sounds great to have an f-stop of f/32 like my favorite lens, but at such a small opening the light scatters more and the edges of objects in your picture aren't as clear. Yes, f/32 creates and an amazingly deep DOF, but at the cost of sharpness.

PROJECT: Learning to to shoot in Aperture Priority Mode.

This project will move you from crawling to walking in your photography. It will start opening doors of creativity.

Read your camera’s manual on how to use Aperture Priority. Every camera will be different. Don’t worry about anything else at this time. Focus only on Aperture Priority.

1. Pull out your camera's manual and find where it talks about how to set your camera to Aperture Priority. Read this section carefully. Aperture Priority means that the shutter will adjust to the setting of you aperture. In other words, if you set your camera to an Aperture Priority of f/8, that setting will remain constant. The shutter will change to give you a correct exposure.
2. Set your camera’s ISO to ISO 400. Don’t worry about what ISO means at this time, just do it. It’s even better if you camera has “Auto ISO.” Then you won’t have to worry about ISO for this project. In a couple of blogs from now I’ll explain ISO. Consult your manual to find out how to set your camera’s ISO
3. Start playing with with different aperture settings. I do this in my living room as I’m watching TV. We’re not worried about what the pictures look like at this time. The only thing we’re trying to accomplish is learning HOW to use your camera in Aperture Priority Mode.
4. NOW THE REALLY FUN PART. Start taking pictures of stuff in your backyard using different f-stops. Make sure that some of your pictures are closeups at different aperture settings. Upload them to your computer and notice what happens with different f-stops. If you’re really geeky you’ll take notes.

LASTLY: I have made a big assumption in this blog, and you know what big assumptions do… Anyway, I have assumed that you understand how your camera’s light meter works, and have a basic understanding of exposure.  

Overexposure is when too much light enters your camera.

Underexposure is when too little light enters your camera.

Your camera has a light meter that tells you when either too much or too little light has entered your camera, as well as the right amount of light. I would suggest that before your read about aperture priority you make sure you know how your camera’s light meter works.

UGH! This is exhausting.

In all of this keep in mind that you want to be able to use your camera in such a way that it helps you become more creative. The hard work you do now will payoff in magnificent ways.

To ask questions you can email me at dougbrauner@yahoo.com.

Join the conversation at Praying With the Eyes on Facebook. http://www.facebook.com/groups/173881749421231/

(Click on picture to enlarge.)

Text and Photographs ©Copyright 2012-14 Douglas P. Brauner.  ARR