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Photography 101 – Lesson 1

Understanding How Your Camera Works Can Help Make You A Better Photographer
11 years ago, February 19th 2008 No: 1 Msg: #27953  
Quite frequently people comment on TravelBlog.org about people’s pictures because there is something about a great picture which captures your imagination. While the best writers capture moments and convey feelings, pictures set a context for what you “see” in your head while you are reading. Thus, spending time creating good pictures is as important for your blog as anything else you do.

The Basics

In its most basic essence, a camera is a light capturing device. Its whole purpose is to gather, focus, and record the light which your eyes see in a given scene. In many ways the camera works like your eyes but, as is true in almost every way, a camera is never as good or as accurate as your eyes and brain are.

In the case of your eyes, you have the basic elements that a camera has. The curvature of your eye acts as a lens, the dilation of your pupil determines the amount of light you collect, and the optic nerve is like a sensor/film. These are the three basic elements that make the camera work to mimic the complexity of a human being. Understanding the parts of your camera and how they work together like your eyes takes some of the mystery out of photography and will help you to better capture, on “film,” what you see.

The Lens

A lens, in its most basic form, acts like the curvature of your eye. Almost all lenses are curved in some way, shape, or form. If you peer into that piece of glass on the front of your camera, you will most likely see that at least one piece of glass back there somewhere is curved. The purpose of this curve is to gather light and focus it on a single point back inside the camera.

The light you see is coming from all around you and is not simply linear or perpendicular to your eye. Actually the light comes at your eye, or your camera, from every angle imaginable. This means that the curved glass in a camera lens gathers that light from many angles (it can never grab it from all angles but it does its best) and bends that light in order to focus the light onto a single point in the back of the camera. Once focused properly this light creates a crystal clear image of the world outside the camera.

A simple analogy to the lens is a pair of corrective glasses. When the curvature of your eye no longer focuses light correctly you start to see a blurry image. When the doctor prescribes glasses for you, he is creating a lens which helps your eye to focus. In this case, the curvature of your glasses helps your eye to focus the light on your optic nerve. Without the curvature of your glasses, you see a blurry image, with the glasses the light is focused perfectly and you see a clear image. This is exactly what the camera lenses does for a camera. Without the lens, there would be no clear pictures, only blurry ones.


In my opinion, understanding aperture is the number one thing that moves photographers from everyday camera holders to novice photographers. Once you understand aperture, you are on your way to becoming the photographer you want to be. Its only the first step, but as the cliché states, the first step is a big one!

Aperture is analogous to the dilation of your pupil. If you have ever marveled at why your pupil gets wider and smaller in certain situations then you will love aperture. Broken down to the most simple explanation (disclaimer: those of you pros out there, please take all of this with a grain of salt, this is meant to be the most basic of explanations) your eye’s pupil gets bigger or smaller depending on the amount of light around you. Standing in the Sahara at noon, your pupil gets very small because there is an immense amount of light around you but, standing in Tasmania on a dark fall night, there is very little light and thus your pupil gets bigger. You pupil acts as a gateway which allows your eye to collect the amount of light it needs. In bright situations the pupil gets small letting less light in, in dark situations, your pupil gets big trying to let as much light in as it can.

Your camera has a device which does the exact same thing as your eye, the aperture. In this case the aperture is directly between the lens and the sensor/film inside your camera. In most people’s case, the camera is set to automatic which means that the camera chooses which aperture you need based on the camera’s opinion of lighting conditions. In bright light the camera will close the aperture and in a dark room the camera will open the aperture up.

In a future lesson we will talk about the importance of aperture and what it can do for you…

The Sensor/Film

In a film camera, the film itself acts like the optic nerve in your eye. It’s a pretty simple thing, at least in concept, that the light gets focused through the lens and aperture (the curve of your eye and the pupil) and focused onto the film. Once properly exposed (meaning the right amount of light falls on the film), a picture is formed just like it is on your optic nerve.

In digital camera this concept is a little more complex. Instead of film you have a digital light-sensing piece of equipment called a sensor. This sensor acts like film in that it interprets light which makes up a picture. Unlike film, the sensor has to pass its information on to a small computer processor in order to actually create a picture. The light enters the camera through the lens and aperture, it falls on the sensor which collects the light, the information is passed from the sensor to a processor where the image is interpreted and finally the image gets stored on a storage device inside your camera (usually a memory card of some type).

The most important piece of sensor information for most photographers is the size of the image in mega-pixels. At the heart of this discussion is that the more mega-pixels present in the image you have taken, the more information there is for you to use later on when you process an image through your computer (using programs like photoshop, corel, etc) and the larger (potentially) you can blow up your picture when you print it (e.g. you can effectively make a bigger picture that is still clear). For simplicity’s sake, we will say, for now, that the larger the number of mega-pixels your camera’s sensory creates, the better the camera (disclaimer: there is a lot more to quality than mega-pixels, there is such a thing as mega-pixel overkill, and there are many other things that create good, clear pictures).

The Shutter

The final important, basic, part of the camera is the shutter. This is the one item your eye does not really use. You could, distantly, consider your eyelids to be a shutter, but it’s a stretch. The shutter rests between your aperture and your sensor/film and works in conjunction with aperture to control the amount of light that lands on the sensor/film.

Since photography is about capturing one still moment it differs from the eye when it comes to light capture. The eye, similar to a movie camera, captures movement and is a continuous process which is always gathering light. The camera acts on a medium, film/sensor, which captures one scene. This means that the shutter allows light to fall on the sensor/film for one instant and then closes the light away. Much like opening and closing a door really fast.

For most of us, we use the camera’s built in logic to choose both aperture and shutter speed (the speed at which the shutter opens and closes). Thus, when you point the camera at the pyramids in Egypt, the camera chooses the right shutter speed and aperture to gather the perfect amount of light to make a picture. This gathering of the perfect amount of light is called exposure (you are exposing the film/sensor to light for a period of time).
Shutter OpenShutter Open

Shutter Open

February 19th 2008

Bring It All Together

You now have all of the basic parts of a camera and understand how they do what they do. As you stand at the pyramids and decide to take a picture you know that the following will happen:

  • The light around you will be collected through the lens
  • The aperture will choose how much light to let into the camera
  • The shutter will open and close allowing that light inside the camera
  • The light will fall on the film/sensor where and image will be captured

In our next lesson we will start talking about how to use these camera parts to better create pictures. Hopefully you learned something…

If you have questions feel free to ask!
Reply to this

11 years ago, February 23rd 2008 No: 2 Msg: #28313  
B Posts: 5,186
Great post Mike - looking forward to lesson 2 😊

Do you plan to talk about ISO soon? Reply to this

11 years ago, February 23rd 2008 No: 3 Msg: #28321  
If you think ISO is a need to know, then I will be sure to add it to lesson #2. I think I'll hit aperture and ISO and should post it some time next week. Glad you liked it...

P.S. If anyone else has things they'd like me to focus on I would be happy to do that...if I can't answer the question I'm sure the other moderators could join in the discussion Reply to this

11 years ago, March 1st 2008 No: 4 Msg: #28934  
Exactly what I needed. Can't wait for lesson #2. I just bought a SLR for my travels but don't really know how to use it correctly. Reply to this

10 years ago, July 30th 2009 No: 5 Msg: #81488  
Brilliant stuff. I just got my first DSLR (very excited!) and so trying to really understand what I can do with it, rather than just use "auto" all the time.
Thanks, Ruth Reply to this

9 years ago, September 16th 2009 No: 6 Msg: #86475  
N Posts: 1
Thats a really nice tutorial ,very well explained. Reply to this

4 years ago, December 3rd 2014 No: 7 Msg: #187206  
Team Turner,

Thank you for taking the time to post this; it is wonderful to get advice from a professional photographer.


Monique Reply to this

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