Photography: Shutter Speed, Aperture, and ISO…Oh My!

Shutter Speed Aperture ISO

When I first started out in photography, the hardest thing for me to do was take my camera out of ‘auto’ mode. I had this nice, new, shiny DSLR. I thought I was hot stuff. I had a camera that needed a neck strap. A neck strap that said ‘Nikon’ in big, bold, yellow Nikon font that I made sure was facing out at all times so people knew I was using a nice camera. The problem was that shooting photos in ‘auto’ meant that every picture looked the same as you’d get from a decent point-and-shoot camera.

To solve this, I switched to ‘manual’ mode. By solve, I mean that all of my photos had a blue or yellow cast, were underexposed, overexposed, blurry. You name a problem, and my photos had it. I thought the same thing many people do: that buying a fancy camera will result in awesome photos. That’s only half true. You also need to know how to use it.

Most articles that I came across at the time explained camera settings using a lot of technical jargon, charts, formulas. You know, all the fun stuff everybody loves to read. You basically had to already know how to use the camera to understand what they were talking about. In this article, we’ll use easy to understand language to explain the most important functions of your nice, new, DSLR camera. If you don’t already have one, go here for a few pointers, then come back and finish reading this…. No, like now. Don’t worry I’ll wait.

Welcome back! Now that you’ve got a camera, let’s talk about the settings. The four most important settings on your camera that you’ll need to be familiar with are shutter speed, aperture, ISO, and white balance. So, set your function wheel to ‘manual’ and let’s get started.

Shutter Speed

When thinking about virtually every setting on any camera, think about light. If you have even a vague notion of film photography (the idea that there is a material that is sensitive to light and displays what light it was exposed to), these concepts will be easier to understand. If not, no worries. It will come together in the end, but keep it in mind as we go on.

Inside your digital camera is a sensor. Think of this sensor as the “film” in a digital camera. This “film” is sensitive to light. The shutter is basically a door between your lens, which lets light in, and the sensor, which reads the light. When you push the shutter button to take a picture, the door opens, exposing the sensor to light. The shutter speed simply tells the camera how many seconds (usually fractions of a second) to keep the door open. The slower the shutter speed (longer time), the more light is let in, and you’ll get a brighter picture. The faster the shutter speed (shorter time), the less light is let in, and you get a dimmer picture. That’s it!

Well, not exactly it. Keeping the shutter open longer also exposes the sensor to whatever movement happens while it’s open, creating motion blur. Sometimes you want that. Sometimes you don’t. More times than not, you don’t. However, if you want to blur a river stream or catch some action in sweet ass lightsaber duel, a slower shutter speed may be in order.

Shutter Speed Aperture ISO

In this case, the movement of the windmill and trees creates a motion blur at a slower shutter speed.


Using what we learned about shutter speed, we know that the sensor is sensitive to light. Truth be told, the sensor is the most important part of the whole process since it’s what’s translating everything we do into a picture. The only direct control we have over that sensor is the ISO setting. This setting tells the camera how sensitive to light the sensor should be. How it does this is not important at this point. Just know that the higher you set your ISO setting, the more sensitive the sensor will be to light and the brighter your picture will be.

Here I've intentionally underexposed the first image and changed nothing but the ISO to brighten the image.

Here I’ve intentionally underexposed the first image and changed nothing but the ISO to brighten the image.

Something very important to keep in mind is that, while your image will be brighter, the image quality will go down. Just like in the days of film, when you tell your sensor to translate the actual light coming into the camera as brighter than it is, the resulting image will have grain, or little static-like dots. The camera is basically increasing the perceived brightness of pixels with a best guess. The amount of grain will vary depending on what camera you’re using, and in most cases, it won’t be very noticeable up to around 1600 ISO (don’t worry about the number too much). As a beginner, you may obsess like I did over the clarity and amount of grain in your photos, but if it comes down to having a grainy photo or an underexposed photo, choose grainy.


I changed other settings to maintain the same exposure in order to show the graining effect of increasing the ISO.

White Balance

This is the easiest setting to manage. Do you know how sometimes you see a photo and say, “I think that looks yellowish,” or “blueish?” That has everything to do with white balance. The camera interprets what color light is coming in the lens, and every light source has a different color. For instance, sunlight has a yellow-red tone. If the camera knows that the sun is the light source, it will counter this by adding blues to neutralize the color (recall your 9th grade art class color wheel). If you set the white balance on your camera to auto, it will make fine (best guess) adjustments the entire time you’re taking photos, and your photos will likely be all over the place in terms of color tone. The best way around this is to get a neutral gray card, set your white balance to custom, have a model stand in the current lighting condition…..

Just kidding. That’s complicated as hell, and I’ve never had much luck with it. Plus, if you change where you’re taking a photo, you have to do it all over again. Just use common sense, and look at what your light source is. If you’re outdoors, set your white balance to the little picture of a sun. If you’re indoors under fluorescent lights, set it to the long, skinny bulb, etc. It may not be “exact”, but your photos will be consistent if/when you edit later. This allows you to make a single adjustment to many photos, rather than a different adjustment for each one. It saves a ton of time and aggravation. NEVER use auto white balance.

These images were all taken under incandescent light using different white balance settings.

These images were all taken under incandescent light using different white balance settings.



The aperture is the setting that everyone obsesses over. It’s also arguably the hardest to wrap your brain around. It basically controls how much light passes through the lens. Inside your lens is something very much like the iris of your eye (the colored part that controls the size of your pupil) called the aperture. This is indicated by f/something (f/1.8, f/4.6, whatever). The lower the number, the more light comes in. Just picture your eye. When your pupil is really big, letting a lot of light in, the number is low (think f/2.8). If your pupil is tiny, letting very little light in, the number is high (think like f/12).

Not only does your image get brighter as your f/number gets smaller, but the amount of the picture that’s in focus gets smaller. Stay with me here. Just like when you focus on your car’s rear-view mirror and everything through the windshield blurs, the camera lens is doing the exact same thing. When you look to the horizon, most things in your view are pretty much in focus. Same thing.


Just remember that whatever you focus on with your camera, as well as anything that is the same distance away from the lens, will be the sharpest thing in the image. Everything ahead of and behind that point will be less focused. Imagine you’re taking a portrait of dear old aunt Betty, and you’re using an aperture of f/2.8 like in the example above. If you’re camera is focused on the tip of her nose, her eyes will be out of focus, and you never want eyes out of focus whenever you’re doing portraiture. Well, not unless that’s your artistic intention.

I really hate to see people spend good money for a piece of equipment and not realize their full potential with it, which is why I started this series. So, don’t be afraid to make changes to settings as you go. In an absolute worst case scenario, where you can’t remember what you changed in order to change it back, just reset it to factory and start over. No worries.

I hope this primer has given you a little better understanding of how the most commonly used camera settings work. Remember that the best way to learn your camera and get better at using it is to use it. So use it!

About Larry

Larry comes to us by way of Huber Heights. He is a lifelong geek as is evident by his bio photo. After a horrible accident in the plastics manufacturing industry left him permanently disfigured, he decided to dedicate his life to making the world a better place. The first thing he did was enroll in nursing school. The second thing he did was co-create this totally awesome website with Josher. Although Larry's English writing skills are similar to that of a bonobo chimpanzee, man is he good with his hands. With Josher's help, as well as yours, he's confident that together they can make the most amazing geek website the world (at least Dayton) has ever seen!
Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *