Your Essential Guide: How to Use a DSLR Camera

Understanding the Basics of DSLR Cameras

If you have ever had a desire to take great pictures, but just didn’t know where to start or how to even begin to operate a camera, then you are in the right place.

I want to start from the beginning and break it all down for you into bite-sized chunks of information.

Before you finish, I hope that you will have enough of an understanding to go from staring longingly at your camera, to fumbling around with your camera, to taking complete control of your camera.

You will find yourself becoming more familiar with not only how the camera functions, but also with how to gain control of the way your photos actually look.

In the next several lessons, we’ll dive right in to the basics of how cameras work, starting with the most basic and overarching concept: exposure.

By the end you will have a much better understanding of not only how your camera works, but also how to control all of its many functions. When I first started shooting, I remember frequently being frustrated with the outcome of my photos.

Step 1 – Mastering Manual Mode

With the camera set to automatic mode, I had no idea how to make the right adjustments to change how my pictures were turning out. Once I finally got a feel for how to operate my camera in manual mode, a huge shift took place in my photography skills.

Finally I was in control of my images. It was freeing to know exactly how to manipulate my camera to make it do what I wanted it to do. And my images became stronger and more consistent as a result.

That’s when you move from simply operating a nice camera and hoping for the best, to becoming the artist behind the camera. Now you are in control of your images and the camera becomes the amazing tool you use to get there.

If you are interested in know exactly what settings I use to shoot my DSLR camera, you can find more details about that here.

In order to begin mastering manual mode, you need to understand a little bit about how DSLR cameras work. This starts with understanding camera exposure.

Step 2 – Understanding Camera Exposure

Before we get into the specifics of operating your camera (and we will get there), it’s important for you to really have an understanding of what exposure means and why it’s important.

Take a look at the following example.

You’ll see the same photograph with three different exposures. When you think of your camera, forget about how advanced the technology has become and all that it can do.

Start thinking about your camera as a light box.

A camera is a device that uses light to create an image. You can control how much light enters the camera by altering a few different functions on your camera. Depending on which one you choose to alter, this will change the style and outcome of your photo.

exposure example.jpg

What is the Exposure Triangle?

The exposure triangle is simply an illustration of the interplay of the three main functions that alter how much light enters into every single camera: the aperture, shutter speed, and ISO.

We will go into what each of these terms mean in a moment, but for now, just understand that they each control how much light enters the camera, each in its own way.

They function individually, but they also work together, hence the triangle figure.

I’m going to go through each of these one by one and how they interact to give you a better understanding of how things work. Don’t worry if it seems confusing, I was too in the beginning. Stick with me and let’s see if it begins to makes sense.

illustration of the Exposure Triangle.jpg

Basically it’s all about light. The camera needs a certain amount of light to properly expose an image. You can let that light in through one of three ways: aperture, shutter speed, or ISO. I’ll go through what each of these means and then we’ll talk about how they interact and why you would choose to change one over the other.

Step 3 – Understanding Aperture

Aperture is how wide the shutter opens up. The wider (or more open) your aperture, the more light is allowed to come in. The smaller (or narrower) your aperture, the less light is allowed.

This is noted by f-stops: f/2 = very wide, f/11 = very narrow. The size that your shutter can open up will vary depending on the lens. Some lenses open up to f1.2 allowing a lot of light in, while others open up only to f4.

photography basics aperature

Step 4 – Understanding Shutter Speed

Shutter speed determines how fast the shutter opens and closes. Shutter speed is measured in seconds and fractions of seconds. A shutter speed of 1″ means your shutter is open for 1 second of time, while a speed of 1/100 means your shutter is open for “one one-hundredth of a second”

What is ISO?

Sensitivity of the image sensor (for digital cameras). This term comes from film cameras where ISO referred to the sensitivity of the type of film being used. 

The lower your ISO, the more sensitive your sensor is to light; and the higher your ISO, the less sensitive it is to the available light.

The ISO on your camera most likely starts at ISO 100 and increases incrementally. These technicals don’t really matter.

All you need to know is that ISO will artificially make your image brighter the higher it goes.

But keep in mind that the higher the ISO, the more grain or ‘noise’ will appear in your photo.

They are all connected.

For any given real world scenario, there will always be a certain amount of light that needs to go into your camera to properly expose an image. 

When you change one of these three basic camera elements, the other two must change as well to maintain that proper amount of light.

Let’s look at a few examples, assuming you are photographing outside, with plenty of available light.


1 – If you open your aperture very wide, it’s going to let in more light. Therefore, your shutter speed will need to be faster, so it lets less light in. Otherwise your image will be overexposed.

2 – Let’s say you want your aperture to be very narrow. It’s going to let less light in than the previous example, so your shutter speed will have to be slower so that it has time to let more light in.

Let’s add ISO into the equation. As a rule of thumb, you generally want your ISO to be as low as possible. For the above situations, if I had plenty of light to work with I would set my ISO at 300 or less and just leave it there. That way all I have to think about is adjusting my shutter speed and aperture. However, there will be times when you have less available light – as the sun is going down or alower light indoor situation. During these times, you may need to raise your ISO. You may also have to keep your aperture very wide and slow down your shutter speed. See how when you change one factor, they all change?

What difference does it make?

You may be wondering why it would even matter which one you change. That’s where you move from just operating a nice camera to actually becoming an artist and taking control of your images. 

There are lots of creative choices to be made that will completely change the outcome of your image depending on which of these three things you adjust.

This is why it’s so important to be able to move beyond shooting in auto mode on your camera. You will have so much more freedom to shoot what you want to shoot!

Let’s go through some examples to see the creative choices you can make when changing each of these.

Examples of Aperture Settings:

A wide aperture creates a shallow depth of field. Great for portraits and blurry backgrounds. Notice in the image below how the trees and the table cloth are blurry and the only area in focus is right around her face? That’s only achieved through having a wide open aperture. 

Aperture: f 2.0 // Shutter speed: 1/4000 // ISO 400 // Canon 35mm
Aperture: f 2.0 // Shutter speed: 1/4000 // ISO 400 // Canon 35mm

In the image below, notice that the leaves are all blurry, bringing focus just to the subject. Again, this is because the aperture is wide open. In this scenario I was working with less light, so my shutter speed is a bit slower and my ISO is higher, but I knew I wanted to keep my aperture as wide open as possible.

Aperture: f 2.0 // Shutter speed: 1/1250 // ISO 1600 // Canon 135mm
Aperture: f 2.0 // Shutter speed: 1/1250 // ISO 1600 // Canon 135mm

One more example of using a wide aperture to focus on one small area of the image – in this case on the blueberries in her hand.

Aperture: f 2.8 // Shutter speed: 1/800 // ISO 640 // Canon 57mm
Aperture: f 2.8 // Shutter speed: 1/800 // ISO 640 // Canon 57mm

Now let’s talk a bit about the times when you may want to use a narrow aperture. These are times when you want everything in your image in focus. In landscape photography, this is usually the case as you are photographing a large area and most likely want it all to be sharp.

Here are a few taken from my honeymoon to Patagonia. Notice that everything from the road in the front to the mountains behind are all in focus. This is only done through using a narrow aperture.

Aperture: f 22 // Shutter speed: 1/800 // ISO 200 // Canon 35mm
Aperture: f 22 // Shutter speed: 1/800 // ISO 200 // Canon 35mm
Aperture: f 18 // Shutter speed: 1/125 // ISO 1250 // Canon 35mm
Aperture: f 18 // Shutter speed: 1/125 // ISO 1250 // Canon 35mm

Note in the above photo that lighting was already limited and I knew I wanted keep a more narrow aperture (allowing for even less light to come in). As a result, my shutter speed needed to be slower to allow more time for light to come in and my ISO needed to be higher.

Examples of Shutter Speed Settings:

Let’s talk about what happens when you change your shutter speed. When your subject is moving, you will need to have a faster shutter speed, otherwise the image will be blurry. It can also appear blurry if your hand shakes or moves at all when taking the photo.

In this photo, the shutter speed was extremely SLOW – 4 seconds long. It gave the effect of motion, which is sometimes desirable and sometimes not. Slow shutter speeds are often used for images at night of a cityscape for example. If you have a tripod, you can set your camera up and use a slow shutter speed to capture lights, stars, etc. You’ll need a tripod or some sort of support though because any motion of your hands holding the camera even for just a fraction of a second will cause the image to be blurry.

Aperture: f 22 // Shutter speed: 4" // ISO 250 // Canon 35mm (camera sitting on the table)
Aperture: f 22 // Shutter speed: 4″ // ISO 250 // Canon 35mm (camera sitting on the table)

Note that because my shutter speed was SO slow, my aperture needed to be very small to let less light in and my ISO very low; otherwise my image would have been overexposed.

Below is an example of when you may want to use a FAST shutter speed. If your subject is moving quickly (as is often the case with children) and you want them to be sharp and in focus, you’ll probably want to keep your shutter speed at least 1/100 or above.

Aperture: f 1.8 // Shutter speed: 1/5000 // ISO 500 // Canon 35mm
Aperture: f 1.8 // Shutter speed: 1/5000 // ISO 500 // Canon 35mm

Step 5 – Understanding ISO

It’s always best to use the lowest ISO possible.

There will be situations, however, where you just don’t have enough light.

You aperture may be as wide as it can go and your shutter speed as slow as you want it to go and you still don’t have enough light. This is when you will have to bump your ISO up higher.

The reason you want adjust this setting last is because using too much ISO will result in grain in your images. The dark areas will have some ‘noise’ to them. The amount of ISO you can use will depend on your camera. Some camera’s are better than others and can be bumped up much higher.

The photo below is an example of where I had no other choice but to bump up my ISO quite high. The photoshoot was taken on a rainy day in a darkly lit nursery. My aperture was as wide as it will go and my shutter speed was 1/40 (just high enough to avoid hand shake), the only thing I could do was raise my ISO.

My camera handles ISO very well and you can still hardly see any noise here. But just know that on most cameras when you start to get above ISO 1000, you are going to start seeing some noise and grain. 

Aperture: f 2.8 // Shutter speed: 1/40 // ISO 2500 // Canon 35mm
Aperture: f 2.8 // Shutter speed: 1/40 // ISO 2500 // Canon 35mm

Step 6 – Practice, practice, practice

I know that was a lot of information to take in at once, but I hope it gives you a good overview of the exposure triangle and the three basic variables that go into operating your camera.

For me it helped to see and read about these things, but when it came down to it, I didn’t fully understand it all until I started playing with it on my camera.

So that’s the next challenge – start experimenting with your camera.

Here’s your homework: begin with shutter speed. Take the same picture with a fast shutter speed and then a slow one and see what happens. And then do the same experiment with aperture. Do this over and over until it starts to really click. You’ll be amazed at how quickly you’ll start to pick things up.

Let me know your questions as you go. What did you learn? What are you still confused about? Can’t wait to hear how it goes for you!

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