Basic Camera Functions


Welcome to the Basic Camera Functions Course! I am your trainer for this course, Chad Naujoks. I have been working in photography in various aspects from wedding and portrait photography to model portfolio work and product photography for about 20 years. I am delighted to be able to help those who are new to photography or just want to get a refresher to catch any little tidbits of information that may help expand their knowledge of photography! 

Why are we teaching about Basic Camera Functions? Well cameras range from the simple just click a button and get a picture to being able to change every little aspect of the photographic process in a menu, but they all adhere to the basic camera functions for creating an image! In this course we will be talking about the Exposure Triangle and how the settings affect the final image captured. We will also be talking about the different focus and exposure settings on current DSLRs (and some point and shoot cameras as well!) as well as white balance and how it affects your images. 

We recommend that you start with this course because everything you will learn from here on about photography will in some way be affected by what you will learn in this course! If you understand all of this course you will be able to apply it in just about any situation that comes your way as a photographer!  

We hope you enjoy this course and as always welcome your feedback! Also, please join the community and share your experiences and questions so that others may benefit from the answers and experiences of everyone else!  

Oh, a little fun fact for those who read this whole thing! 😊 On top of your camera there is usually a little icon that looks like –o–. That is exactly the film / sensor plane. This was used back in the day and to a lesser degree today for those times where you need to figure out exactly how far your subject is from the sensor to be sure they are in focus using a little window on top of your lens set to the exact distance in feet or meters. You may remember in school that when you got your picture taken they would hold a string up to your face to measure your distance to the camera. That is what that little icon is for! 

Chapter 1: The Exposure Triangle
Yay! Geometry! No, just kidding, we aren’t going back to high school math just yet. The exposure triangle shows us the interaction of the main three settings that affect the exposure (brightness) of an image taken with a camera. The three pieces being ISO, Aperture and Shutter Speed. Each of these work together to control the amount of light recorded on Film or the Digital Sensor in your camera. Aperture and Shutter Speed directly affect the amount of light that gets to the sensor while ISO acts like a volume knob on your stereo telling the sensor how much to turn up the light that reached the sensor when it records it to the memory card!

All of these settings are measured in Stops. In order for an image to maintain the same brightness if you change one of the settings by one stop, you will have to change another setting one stop in the other direction. I know, it sounds worse than it really is! Let’s look at an example. If I know that a perfect exposure for an image I wish to take requires and ISO of 100, an aperture setting (f-stop) of f/2.8 and a shutter speed of 1/500th of a second and I want to change the shutter speed to be slower than 1/500th I can set it to 1/250th of a second (1 stop slower). This by itself would make the image brighter (since the shutter would be open twice as long as it would for the perfect setting!) so to make the image perfect again I would have to change the ISO or Aperture by one stop to compensate, so either the ISO would have to move up to 50 (turning the volume down to half on the output of the sensor) or change the aperture to f/4 (allowing half the amount of light through the lens). We show more examples in the video, don’t worry, you will get the hang of this over time! No problem!


In the next sections we will go over each of these three settings and how they affect the photograph directly and why you would want to change these settings rather than letting the camera just choose them for you. This is your first step to getting off of the little green auto setting on your camera!

Chapter 2: ISO
ISO, some people refer to as the sensitivity of the sensor. This isn’t specifically correct, but it does act in the same way! ISO is like the volume of signal that comes from the sensor when it saves the image to the memory card. Raising the ISO setting on your camera will make your images brighter, but will also introduce noise (grain) into your images.

All cameras have what is called a base ISO. It is usually the lowest setting, but not always, some cameras have settings like Lo 1 and Lo 2 which are kind of like turning down the radio below 1. The sensor works with no negative or positive amplification at the base ISO. At this setting the image will have the least amount of noise or grain that the camera can produce.

A few things about the camera will affect the noise of the image, the size of the pixels on the sensor, the software that the camera uses to record the image to the memory card. In another course we discuss Megapixels and how they affect images and how many you need to get the images you are after. But, for now just know that each pixel on a sensor is like a bucket that holds light. The larger the bucket the more light it can carry and the more information the camera will have when saving it to the card. The more information the camera has when saving the less errors there are (noise) when it tries to figure out exactly what color that pixel is. The larger the sensor is physically, the larger the pixels can be on the sensor which of course allows each pixel to gather more light!

Newer cameras have better software and faster computers in them to help reduce the amount of errors when saving the image to the card which reduces the amount of noise. So between the size of the pixels and the newer computers and software, images have gotten a LOT better since the first digital cameras. Newer cameras can make very usable images at higher ISO settings up to and including 6400 and sometimes 12800 ISO. Sometimes black and white images will have a very nice look with a little more noise allowing you to push your ISO settings much higher.

Most (roughly 90%) of all images taken will be taken at the base ISO of the sensor, only during special times will photographers increase the ISO to get an image. When you have your shutter speed and aperture set to get a specific look for an image you are after and the picture still needs more light, that is when you would change the ISO to make up for the difference. As a rule (meant to be broken) you should start out trying to keep your ISO as low as possible or as close to the base setting as you can get!

Chapter 3: Aperture

Now we get to something a little more common! As you start your journey into shooting in manual and changing the camera settings to suit your vision, aperture and shutter speed are the two settings you will change most often, sometimes between each and every image! First let’s talk about Aperture and how it can affect your images.

The values available to you for your aperture are called F-Stops or F/numbers and vary based on the lens that you have on your camera. But, what exactly is Aperture? Well, the simple answer is that Aperture is a hole in the lens that lets light through to the sensor. F/numbers range from f/1.2 to f/64 depending on your lens. There are some that lay outside that such as the Nikon Noct 58mm f/0.95, but most have ranges between f/1.8 and f/22.

The math behind these number is that the f stands for the focal length of the lens and devide that by the number below the / to get the diameter of the actual aperture of the lense (the opening that lets the light through). So if you have a 100mm lens and you use f/4 for the aperture setting the hole in the lens will be 25mm (100/4) across. This is also why lenses with very low f-stops are so large (physically) the Noct mentioned above is a 58mm lens, but with a f/0.95 has a 61mm opening, making the lens much larger than a normal 50mm lens with a f/1.8 aperture (only needing to be big enough to have a 28mm opening!)

The smaller the value of the f-stop the larger the opening of the hole in the lens. As you move the aperture from f-stop to f-stop the opening lets in half as much or twice as much light. So f/4 will let in half as much light as f/2.8 and f/2 will let in twice as much light as f/2.8. The standard f-stops are:

f/1.4   f/2   f/2.8   f/4   f/8   f/11   f/16   f/22

Another thing that changes with the aperture is the Depth of Field (DoF). As the opening gets wider (the f-stop number goes down) the DoF gets more shallow (or small). Less of the image will be in focus. In general about 1/3 of the DoF is in front of the subject you are focused on and 2/3 is behind the focus point. As you increase your aperture setting (higher f-numbers) you will increase your DoF but will decrease the amount of light you let into the sensor.

As you remember from the exposure triangle, if you reduce the light coming to the sensor with one setting, then you have to compensate with one or both of the other settings, depending on what your needs are for the image and how much noise you can accept in the image.

Depending on the type of photography you are doing and your subject, the aperture you use will vary widely. Landscape photographers tend to use really small apertures (high numbers) and macro photographers and portrait photographers shoot with larger apertures to help blur the backgrounds more and isolate the subject they are photographing.

That about covers the basics of the Aperture settings on your camera, there are in depth math problems that deal with Depth of Field and something called Hyperfocal Distance that we will be covering in a much more advanced class in the future! Keep and eye out for it!

Chapter 4: Shutter Speed
Now the fun setting! Shutter speed! Everyone is familiar with 1 second, we all know how long a second takes to pass, but how often do you get to stop motion down to what happens in 1/4000th of a second, sometimes 1/8000th of a second?! Wow, that is fast! This is what shutter speed allows you to control. How long the shutter stays open to let light in to hit the sensor through the hole created by the aperture.

Shutter speeds on cameras now are very fast but can also be open for a long long time. Most cameras will allow you to keep a shutter open as long as the battery holds out. Each stop in the shutter speed will increase or decrease the amount of light allowed to hit the sensor by half or double. A shutter speed of 1/500 allows in half the amount of light as 1/250th of a second, whereas a shutter speed of 1/125th of a second allows in twice as much light as 1/250th of a second.

Faster shutter speeds allow you to stop motion and the slower shutter speeds will allow you to blur motion. If you use a fast shutter speed like 1/2000th of a second, you can capture the wings of a flying humming bird without blur. If you would like to get the soft silky look of moving water you would use a longer shutter speed like 1 second or more.

Some people believe that you have to have a fast shutter speed and luck to catch lightning. This isn’t true! As long as you have a dark enough environment you can use a longer shutter speed like 5 to 10 seconds or even longer with a medium aperture such as f/11 and capture a bolt of lightning and sometimes depending on the storm, more than one!

The faster the shutter speed, the less light is allowed to hit the sensor, which means you will have to use a wider aperture (lower numbers) or higher ISO (more volume) to compensate and get an image that you can use. This completes the exposure triangle! Now you know all the settings that affect the brightness and other aspects of an image!

Chapter 5: Focus Controls
There are many different types of photography and most of them have settings in your camera that will help you get the image easier and sometimes make your images better. We have already talked about the times where you would like a shallow depth of field, or you want to try to stop motion. But now we are going to talk about how you can set up your camera to make sure your subject is in focus, not matter what the situation is!

There are many different settings you can change on most cameras for controlling how your camera will focus on the subject you want (and sometimes if the settings are wrong, it will focus on things you don’t want!) First I wanted to talk about manual focus. You can set this most of the time by a switch on the front of the camera. You can see in the images below there is a switch around a button on the front of the Nikon cameras that allow you to make this change and some of the lenses also have a switch on them to turn on AF or Manual Focusing. For the Canon Cameras, all of the switches are on the lenses, there is no switch on the bodies to change this setting.

When would you want to use manual focus? While the cameras today are really good and do a great job at getting focus, even some of the newer ones will focus on the eye of your subject automatically, there are still times that you would have to or at least want to use manual focusing! One example of this is if the scene is too dark for the autofocus to work correctly and it just keeps hunting back and forth and never really gets a good focus in auto mode. This happens a lot in the studio when you don’t have the lights on and are depending on flash for the light, it isn’t on while you are trying to focus and it is just easier to get focus manually and leave it there for the duration of the shoot (as long as your subject doesn’t move from the focus spot!)

Now let’s look at the myriad of auto focus settings that most cameras have available to them today, and yes, there are many! The main two settings that most people will be interested in are Single and Continuous focus. Single will allow you to hold down the focus button to get focus and it will hold that focus until you lift your finger off and press it again, allowing you to recompose the image before taking the shot and staying focused on the subject you chose. Continuous focus does exactly what it sounds like, as you hold down the focus button the camera will continuously try to focus on what is under the chosen focus point in the viewfinder.

Another setting that is generally used with regard to focusing is the focus point, or the number of focus points to be used. Newer cameras have a LOT of focus points available and will let you use one, some or all focus points when trying to decide what to focus on. While using one focus point will give you a lot of control over what part of the scene to pay attention to when focusing, allowing the camera to choose between some or all of the points is sometimes a good bet, especially if you have an erratically moving subject like during a soccer match, for example.

When you change the setting to use one or just some (7, 9 or 15 points for example, as all cameras are different) you can also control which one to use, or which one to center the number of focus points around in the scene to help you focus on your subject without having to recompose your shot after focusing.

One thing we need to touch on is Back Button Focus and we will cover that in the next section!

Chapter 6: Back Button Focus
One question just about everyone asks about focusing at some point is, What is Back Button Focusing?! Well, the short answer is using a button on the back of the camera to focus and making the shutter button no longer focus when you press it down half way. Now how you set that up and why you would want that is a much longer discussion!

Why would you want to take the focus off of the shutter button?!One of the main reasons is that you can control things much better and use continuous focus all of the time rather than having to turn it on in the settings each time you want to switch between single focus and continuous focus.

Since you will have the focus control on the back button in continuous mode you will be able to hold down the back focus button to continually focus and press the shutter when you want to take the image, which would let the focus act in continuous mode. You can also press the back button to gain focus on a stationary object and then let the back button go then press the shutter button when you are ready to take the image. This time the focus would act like single focus and the camera wouldn’t try to refocus when you press the shutter button.

Another time that this comes in handy is when you are in a situation where you have to focus then recompose and shoot again, or you have a subject that isn’t going to move often (or at all for still life!) Then you can set your focus with the back button and recompose as much as you want before you take the picture without worrying about the camera trying to refocus when you press the shutter.

Now setting this up depends on the camera you are using. But on most of the newer cameras they have a dedicated button on the back of the camera to set AF-ON (Auto Focus On). The steps are usually the same, but are done differently, and the only way to really know how to do it for your particular camera is to google it or look for a video on YouTube for your particular camera.

Step 1) In the menu system for your camera find and set Assign AE-L/AF-L button – Press = AF-ON
Step 2) Turn on AF-C (Nikon) or AI-Servo (Canon)
Step 3) Test to see if the camera focuses when you press the shutter down half way (It shouldn’t) Then test if the button you chose to assign AF-ON to starts the lens focusing (It should!)

Remember if you can’t find the menu item or figure out how to turn on AF-C or Continuous Auto Focus, be sure to check your camera manual or search for a video on your particular camera model on YouTube or google! There are a lot of videos on back button focusing on the internet!

Chapter 7: Exposure & Metering
Getting the correct exposure for your image and the vision you have for the final photograph can seem difficult after everything we have talked about in this course, but truly the camera has a lot of features meant to make sure you have the information you need to get the correct exposure for the outcome you are looking for! In this section we are going to discuss the camera meter, external light meters and how to use the information that they give you to get the perfect image!

All meters inside of cameras are reflective meters, meaning they make the exposure calculations off of the light reflected from the subject the camera is pointed towards. Hand held light meters can work both in reflective like the camera, or in Incident which calculates the exposure based on the light falling directly on the meter. Depending on the scene or subject you are shooting an incident light meter may not work, but a reflective meter will always get you at least a good reading of the scene. An example of a scene that will not work with an incident light meter would be a landscape or scenery shot where you wouldn’t be able to go stand in the landscape and take a reading (since it would be so far away and by the time you got back to where you wanted to shoot from, the lighting would have changed!)

Light meters, whether they are hand held or in camera all try to average out the scene to 18% gray (middle gray). So if you point your camera at a white wall and take a photo with the settings that the camera gives you, the white wall will come out gray in the photograph. The meter doesn’t have a brain (so much, though it is getting better!) so it can’t know what it is in the scene you are trying to shoot, so it averages out the whole scene to 18% gray and expects you to make changes based on your knowledge of what is in the scene.

Newer cameras (well most consumer level and mid-level cameras) have various Scene Modes available, which change how the metering system “sees” the scene to meter off of it. It will change how much it weighs a certain part of the scene or how it reacts to the light in a scene to give a better guess at what the perfect settings will be for a particular image. Even with these, it will not get every scene correct and you should know how your system meters so you can know how to make changes to your exposure triangle to get the perfect exposure for your photographs.

Most cameras allow you to change the metering mode between usually three different settings. Spot metering allows you to meter off of a small circle of the frame centered on the selected focus point. Center weighted metering is exactly that, it meters off of a larger circle than spot metering in the center of the frame. The last on a Nikon is called Matrix Metering and Evaluative Metering on a Canon, where the camera tries to figure out a balance of light and dark areas in the scene and give it’s best guess as to the shutter speed and aperture for the current scene.

Now that you know how the camera meter works and what it is going to give you, there is another setting on your camera that allows you to change your exposure while still letting your camera take the meter readings and not having to think so much about the changes you have to do with Shutter or Aperture. Exposure Compensation tells the camera that you want to take what the camera reads the scene to be and add or subtract up to 5 stops, some cameras allow for more than others, but 3 to 5 stops is usually the range they let you set.

One example where you would use this that is very obvious is when taking a picture of a snowy scene. You know that the snow is white, but the camera wants to make it roughly 18% gray as we mentioned before. If you know you are shooting in these conditions, you can use exposure compensation to let your camera know you want the snow to be white by setting it to over expose by 1.3 to 2 stops and the camera will slow down the shutter or open the aperture some to make sure it allows that much more light hit the sensor from what it thinks the scene should be (18%)

As you can see, there are many tools and options on those tools to help you get the best picture you can for any given scene, but they are all just tools and will not do all of the work for you! Knowing them and how they work as well as how to control them and their settings will help you get the best information from them, but in the end it still comes down to you and your vision to make sure the image is exactly as you wish it to be when you press the shutter button.

Chapter 8: White Balance
Another setting that just about every camera has now (at least the digital ones, if you want to change white balance on film, you have to buy different film!) is the White Balance settings. Every camera has a similar set of settings for White Balance that include Auto, Daylight, Shady, Cloudy, Tungsten and Florescent. Some cameras will allow you to set the exact Kelvin setting of the light you are shooting in and event adjust the tint of the final image. Though the presets are usually really good at getting close and fixing a little bit in post processing.

While Auto White Balance has gotten a lot better since it was introduced, it is still just guessing the best it can on what it can see in the scene (kind of like the light meter, it doesn’t have a brain either!). Choosing a preset closes to the situation you are currently in is usually the best, unless you can just not figure out which preset will be the best for your image. If you know exactly what temperature the light is that you are using (usually in a studio setting) then you should change the Kelvin Temperature to match in the custom white balance settings.

If you accidentally use a wrong white balance setting for your scene such as setting White Balance to Tungsten when you are shooting outside on a sunny day, your image is going to be very tinted. Sometimes it will be orange, or blue, sometimes green (in the case of Florescent lighting!). Once you see this you should try to choose a closer matching White Balance preset or put the setting to Auto and let the camera figure it out.

This is one of the settings that you can use in Auto all of the time if you would like as long as you are shooting in RAW. If you are shooting in RAW the White Balance isn’t actually applied directly to the image. The White Balance setting is saved in the RAW file and applied to the image in the editing software when you open the file. This way you can make changes to the white balance settings in the editing software without messing with the actual RAW data from the camera. If you are shooting JPG though the White Balance will be “baked” into the final file. You can still edit the colors of the JPG file in an image editor, but then those changes are “baked” into the new JPG file.

White balance can also be used to change the feeling of a photograph, warming it up or cooling it down by using a different preset or custom white balance that is a little off from what a perfect setting would be. For example sometimes you take an image during around noon, but the image seems to lack warmth, the quick fix for this is to change your white balance to shade which will warm up the image a little bit.

Chad Naujoks


I have been working in photography in various aspects from wedding and portrait photography to model portfolio work and product photography for about 20 years. I am delighted to be able to help those who are new to photography or just want to get a refresher to catch any little tidbits of information that may help expand their knowledge of photography!

Free Courses

Duis egestas aliquet aliquet. Maecenas erat eros, fringilla et leo eget, viverra pretium nulla. Quisque sed augue tincidunt, posuere dui tempor.

Premium Courses

Duis egestas aliquet aliquet. Maecenas erat eros, fringilla et leo eget, viverra pretium nulla. Quisque sed augue tincidunt, posuere dui tempor.

Ready to get started?

Get in touch, or create an account