Which Aperture is Best?
by Chris Daniels

Which aperture is best? A question that you may be surprised at how often it’s asked. To answer it most simply, just as your kindergarten teacher said of you and your classmates, “each one of you is special and unique in your own way” and the same is true of aperture.

What is Aperture?

First, let’s take a look at what exactly aperture is. The general definition of aperture is; an opening, hole or gap.

Specific to your camera, aperture is the opening of the lens’s diaphragm which light passes through to your film or sensor.

Photography itself is defined as; the art or process of producing images by the action of radiant energy and especially light on a sensitive surface (such as film or an optical sensor)

You can just say that photography is the process of capturing light and aperture is one of your native tools that allows you to control and even manipulate how you do that.

The general rule of aperture is that the larger the opening (that’s the size of the opening of the diaphragm in the lens) the more light you take in. In relation, the smaller the opening the less light you take in. That opening is measured in “f/stops”. You’ll frequently see things like f1.2 or f11, etc. It may seem a little contradictory, but the smaller the number the more light the camera takes in. Think of it as “small number = large opening”.

Now, before you just say “GREAT! Give me that 1.2!” you have to know that you are making a trade here. Newton’s third law still applies to photography and every action you take effects something else down the line. In the case of aperture, we’re making trades with the depth of field. The lower the f/stop - the more shallow the depth of field.

Here is a simple comparison example:

These two images were taken with the same lens, using both its most open aperture (f1.2) as well as its most closed. (f16)

The depth of field on the left image (f1.2) is so shallow that only the most immediate focal points retain any sharpness at all. It does make for a very soft and pretty image but you have to be careful with such a low focus range. f1.2 is low enough that if you were to take an up-close portrait at that aperture and accidentally focus on the subjects eyelash instead of their eye the image would be out of focus. Trust me, I’ve done it. The upside is that you allow a lot of light in!

In comparison, the image shot at f16 has detail in abundance. You could easily count the veins of the leaves. Furthermore, you can see the detail of all of the leaves and that is because the more closed the aperture (especially f8 to f16 and beyond) the greater your depth of field. You must pay a price for this detail though and the payment demanded is exposure.

See the settings of each shot below.

In each shot, the ISO has been unchanged and left as a constant with our only variables being our aperture settings (f/stops) and our shutter speed.

In the first image, at f1.2 I allowed in a lot of light and for a balanced exposure still had my shutter speed at 1/1000 s! At that speed, you can shoot hand-held all day long and stop most any motion you want! You’d better be sure you get your focus on point though, being at f/1.2!

The second image, at f16 locked down a lot of my light. To shoot at that aperture and still get enough light for a proper exposure I had to take my shutter speed all the way down to ⅛ s! I don’t care if you’re a Chevrolet, you’re not solid enough to hand-hold a camera and still get sharp focus at ⅛ s. This shot had to be set up on a tripod. That detail though…

So, What Aperture is Best?

So, really, here’s what it comes down to if you ask which aperture is best: The best one is the one that you need at that moment. If you’re shooting a wedding and the sun just dropped away out of nowhere you’re still expected to get the shot and that f1.2, crazy shallow depth of field or not, just saved your ass!

Alternatively, if you’re in the Utah desert and aiming to capture every spectacular little detail in a wide-angle landscape shot break out the tripod and close that puppy down! It’s what you need!

Even these are not hard and fast rules. Once you’re really comfortable with using aperture in multiple settings you’ll learn that it can be one of your greatest artistic choices and really contribute to the voice of your image and composition. There may even be another article in the near future about that very thing. (wink wink)

For now, practice and experiment all you can. I’ve been shooting for a long time now and I still practice, play and experiment. I personally like to think of things in constants and variables. “What if I shoot all day in f16? I can change anything else as long as I stay in f16.” You would be surprised at what comes of things like that. Those kinds of experiments and play are the very things that have pushed me forward in my own knowledge and understanding of this wonderful medium as well as my own personal artistic style and voice.

Happy shooting, friends!