So…What Does Aperture Mean? Shutter Speed? Or Even ISO?

Learning photography is really fun….seeing the amazing work of others who have figured out how to capture so many amazing images, really motivates me to learn more about it as well, and apply these principles to my own adventures.

There is nothing like the challenge of capturing the amazing landscapes that we see, and recreating it for others to experience, along with keeping a vivid photographic record of your travels. These images can be used to show others some great locations you have found, or at least let them experience the awe that you had experienced, merely by looking at great capture of the scene.

The cameras on today’s cell phones and basic point-and-shoots do really well at capturing these imagined images a lot of the time, since you can use basic composition traits (see my earlier blog post) and its built-in auto adjusments to capture some striking and colorful images.

When I first got my DSLR camera, I used automatic mode for almost a year, until I learned of these concepts I’m about to describe. This understanding allows me to shoot completely manual, and I have never looked back.

Sometimes you need more control to capture an image exactly how it is, and the scenic features you want to highlight. This is where manual or even semi-automatic control of your camera functions come into play.

Here are some basic definitions of the 3 main variable settings (aperture, shutter speed, and ISO) that will allow you to recreate your images with more detail and precision!

The aperture is the “opening” within the camera lens that allows a set amount of light to pass through.

Since I am in the eye business, I cannot help but to constantly compare a camera lens to the human eye.

The glass of the lens is like your cornea, the clear part of your eye that lets the light pass through.

That being said, the colored part of your eye (the iris), is the muscle that expands and contracts to either let more or less light in. The black opening, created by your iris, where light passes through is called a pupil….on your camera, this “pupil” is the aperture.

This opening is a bigger or smaller circle, depending on the amount of light you want to be processed by your retina (in your camera, this is called the image sensor).

And instead of using moistening eye drops to see better, you can use a cloth and cleaner on your camera lens, and…..okay, okay, you get the point.

Shutter Speed

Also known as exposure time, the shutter speed determines how long the image is displayed on the image sensor, thus creating the photo. Measured in seconds, for most situations you will be shooting faster than 1/60th of a second. It is said that “camera shake” is to occur at shutter speeds slower than this. These situations will require a tripod, more on this later.

A slow shutter speed will add more light your photo, and a fast shutter speed will let less light in.

Understanding this process will determine whether or not you under or over expose your photo. A fast shutter speed will also prevent fast moving objects from being blurred, this is important when taking pictures of wildlife.


ISO stands for….nothing, actually.

It is not an a acronym directly relating to photography, but it does, however, represent the light sensitivity of your camera. By adjusting the ISO settings, you are effectively adjusting the amount of light that is processed in your photo, without having to adjust the aperture or shutter speed and leaving them where you want.

In normal or bright light situations, your camera should capture the image with the proper exposure at 100 or 200 ISO.

If you are in a low light situation, you may have to try to use a slower shutter to capture the proper amount of light, for a properly exposed photo.

This is not always a good solution, since you may run into the aforementioned camera shake, giving yourself a blurry photo.

You could decrease the aperture to let more light in, but this will affect the depth of field that you’re trying to accomplish.

Therefore, ISO should be your last attempt to get the proper amount of light. Raising the ISO incrementally will enable you to keep your aperture and shutter settings where you want them, and still properly expose the photo.

Night photography requires a high ISO (1600 and above), and even when shooting in a darker forest at a set aperture and shutter speed, my ISO is at 800–1000.

While this is necessary for proper exposed photo, the drawback to increasing ISO means it will add more grain to your pictures.

Here is the settings display of my camera. The M stands for manual, while the 3 values to the right of it are the shutter speed of 1/60, aperture of 8.0, and ISO of 800.

Now that I shared what I have learned about the basic principles of these 3 settings, I will go into more detail and the settings that work for me in upcoming blog posts!

See you soon!

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Learn some great hiking and photography tricks, while preserving our amazing wilderness!

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