Lesson 1: Camera Components

Photographic technology advances quickly. The last 150 years have been a nonstop parade of change as we’ve moved from chemical-based imaging technologies to current digital offerings. Along the way we’ve also gotten, automatic focus, artificial lighting, faster performance, and much much more. Through it all though, the basics of the camera have not changed. It may sound strange but at a fundamental level there’s no difference between your current digital camera and the earliest cameras of the nineteenth century. All cameras, even your cellphone camera have the same basic components. They all have a light proof box. This holds the photosensitive material that will record an image and it has to be light proof because you’re trying to capture and record light, so you can’t have any extra light around. Most cameras also have a lens. This is a piece of material that gathers light that’s bouncing off of your subject and refracts or bends that light to focus it onto the light sensitive material that’s sitting in your light proof box. Most lenses are glass, but they can also be made of plastic, water, any substance that can refract light. All cameras have an aperture. This is simply a hole in front of the light sensitive recording medium. Most cameras have an aperture that can vary in size, this is called an iris. But it’s possible to have a tiny aperture of a fixed size which can do double duty as a lens. That’s how a pinhole camera works. A camera must have a shutter. This is simply a door that can open and close for a certain amount of time to allow light to enter the light proof box. By opening the shutter you expose the light sensitive material inside the box to the light that has been passed through the lens and the aperture. Now, photographers sometimes refer to a photo as an exposure because the process of photography is simply the process of exposing a light sensitive material to carefully focused light in a light proof box. Every camera ever made has had the components that we are talking about right now. In a way, photographic technology has been astonishingly stable throughout its history. One thing that changed with great regularity is that light sensitive material that you put in that light proof box. In the earliest days you might have used wet chemicals smeared on glass plates, or complex mixtures of silver powders and saw dust or colored starches. I would argue that the most fundamental change in camera technology since its invention has been the shift from film to digital. In a digital camera we’ve replaced the light sensitive film, that used to sit in the back of the light proof box with a chip that’s covered with light sensitive material. We’ve also crammed in a computer and a bunch of storage which can read the signals coming from that light sensitive material and use all of that to produce an image. A lot of technologies remain constant at a fundamental level. All cars have had wheels with rubber tires, steering wheels, and an accelerator pedal even as they’ve gained fuel injection, electronic variable suspension, and cupholders. However, you don’t need to know how fuel injection or carburetion works to drive a car. To use your camera well, though, you do need to understand the workings of some of these fundamental camera components. To shoot well, consistently, you must know about some of the deeper workings of lenses, aperture, shutter, and your recording technology, be it film or a digital chip. Those are some of the things we’re going to begin to study in the rest of this course. Now while fundamental camera parts have remained consistent, camera design has changed a lot over the last century and a half. This is partly because as film changed size new camera designs had to be created, but most new camera designs have come along to address a single problem. Let’s say I have a piece of film or an image sensor. In front of that I put a shutter, and then an aperture, and then a lens. With all that stuff in front of the imaging material, how can I actually see what I’m taking a picture of? The shutter is closed, which is blocking all of the light coming through the lens, and even it it weren’t there’s that piece of film or image sensor there behind the lens. The attempt to make a usable viewfinder has been one of the biggest factors driving camera design. But designers also have to factor in physical size, size of the recording medium, and much more. Because of all of those reasons, there are several categories of camera that you can buy now. In the rest of this chapter, we’re going to look at those different camera designs to help you understand the advantages and disadvantages of each. This will make it easier to choose a camera and help you to understand why you might want to have a couple of cameras in your shooting arsenal.

SLR, single-lens reflex, that’s what these two cameras are right here. This is the camera design that people think of when they think of a serious, or a professional camera. And until a few years ago, this was the only viable option for a serious or professional photographer. Nowadays though, the camera landscape is a little more robust but there are many, many advantages to an SLR. The name, single-lens reflex actually explains the main advantage of this design so all we have to do is take apart that acronym to understand how this type of camera works. Single lens, sure enough, there’s only one lens on this camera and you may think why in the world would it need more than one? But there have been many camera designs down through the years that have employed multiple lenses such as this twin-lens reflex. The lower lens here is used to expose the film while the upper lens is used as a viewfinder. This is kind of a brute force way to get around the problem of the film preventing us from being able to look through the main lens here. The problem with having a second lens for a viewfinder is that you don’t see precisely the same composition as the lens that’s exposing the film because the lenses are in slightly different locations. Also, you can’t see the effects of any filters that you might have placed over your main lens which can make it difficult to properly set filters and to visualize their effects. With a single-lens reflex, I look through the same lens that exposes the sensor or film, sensor in this case. This is achievable through a combination of prisms and mirrors. Less expensive cameras might do it all with mirrors. If I take the lens off, you can see that here inside the camera there is a mirror so what’s happening is light is coming through the lens, it’s bouncing off of this mirror and going up. When it gets up into here, there’s a prism or a series of members that bounces the light back through the viewfinder. So I am able to look through this viewfinder out the same lens that’s exposing the sensor. However, it can’t really expose the sensor right now because this mirror’s in the way. So when I press the shutter button, the mirror pops up, the shutter opens and what you’re seeing right there is actually the sensor. You can see it’s got this kind of weird iridescent thing that it does. Then when the exposure is over, the shutter closes and the mirror comes back down. With the mirror up like that, my viewfinder is now blind. That’s why when you take a picture with an SLR, the viewfinder blacks out for a moment because its light path out the lens is getting cut off. Most SLRs allow you to change the lens, and this is a wonderful feature. Interchangeable lenses give you a fantastic level of control over the quality, focal length, and lens characteristics of your camera. The downside to an SLR is that it’s large. The camera body has to be big enough to hold this mirror as well as the prism or mirror arrangement that’s up here and it has to have space for the optical viewfinder that’s behind all of this. All of that takes space and those components contribute weight to the camera. Because of the mirror in front of the sensor, the lens has to be pretty far from the focal plane and that means that the lens itself needs to be bigger to project a large enough circle of light to cover that distance and completely cover the sensor. That adds more weight. Remember, the weight of a camera system includes all of the lenses that you carry with you also. So an SLR and a bag of lenses can quickly get heavy. SLRs fall into two major categories, full frame and crop sensor. The terms refer to the size of the image sensor in the camera and there are advantages and different disadvantages to different size sensors. With a bigger image sensor, the individual pixels on the sensor can be made larger. This camera has a larger sensor, and if I pop the lens up here you can see it as compared to, whoops, compared to this one. The larger sensor makes it possible to capture an image with very little noise. Noise is that speckled grainy stuff that sometimes appears in an image. You’ll usually see less noise in a camera with a bigger image sensor. Depth of field is a term that we’ll look at later, but it’s basically how deep the focus goes in your image. Sometimes you’ll want a very shallow depth of field to blur out the background and bring more focus to your subject. A larger sensor allows for much shallower depth of field than a smaller sensor. Smaller sensors, though, let you create smaller cameras and because they have inherently deeper depth of field they’re great for situations where you want everything from near to far to be in focus, landscape photography, for example. Finally, cameras with smaller sensors are usually cheaper. Full frame means a camera with a sensor that’s the same size as a piece of 35 millimeter film. Cropped sensor means a camera with a sensor that’s smaller than a piece of 35 millimeter film. It’s a crop of that larger size. SLRs currently come in a range of sizes and weights with a variety of interfaces and features. Their flexibility, performance, and image quality make them great options for any type of shooter.

In addition to SLRs, there’s another category of camera that also offers interchangeable lenses and larger sensors than what you’ll typically find in a point and shoot camera. People struggled for a while with what to call this category of camera, but the name mirrorless seems to have finally stuck. Now that you know what an SLR is, the term mirrorless should make some sense. A mirrorless camera does not have a mirror in front of the sensor. That means there’s no need for a prism up above; there’s no need for a mirror chamber inside. The lack of prism and mirror means that the whole camera body can be made much smaller than an SLR; however, without a mirror and prism, there’s no way to have a view finder that looks through the single lens that’s on the camera. Instead a mirrorless camera has an electronic view finder, what is often called live view. This is the kind of view finder that you have on a camcorder and on some point and shoot cameras. Your cell phone camera has one, and live view is an option on many SLRs. A sensor is used to capture an image in real time and that’s fed to the view finder or the screen on the back of the camera. Now as I mentioned, because they don’t need a mirror chamber in front of the sensor, or a pentaprism on top of the camera, mirrorless bodies can be made much smaller than an SLR body. Without the large mirror chamber inside the body, the lens doesn’t need to project as big of an image circle so the lenses can also be made smaller than their SLR counterparts. All of this adds up to an overall system that can be dramatically lighter, smaller, and easier to carry than an SLR and a bag full of lenses. When choosing between an SLR and a mirrorless camera, your biggest concern will be the view finder. The optical view finder of an SLR is great and bright light; it allows you to see the full range of highlights and shadows in a scene. Electronic view finders can be more difficult to see in bright light, but show much more in low light than an SLR view finder. But they also might obscure shadow details which can make composition a bit more complicated. On the other hand, they show a much more accurate view of what the final image will look like. Both SLRs and mirrorless cameras have their advantages and disadvantages, and both are capable of producing professional grade work. Before you choose, though, you might want to give a little thought to lenses.

There are a lot of complex parts in a modern camera but one of the most critical components is the lens. It’s the lens that focuses the light from your scene onto the image sensor in your camera. And different lenses will do a better or worse job of focusing that light. A superior lens will yield an image with sharper details, better contrast, richer colors. Also sometimes, a lens just has an indefinable quality that you might prefer, even if you can’t identify exactly why. But image quality is not the only thing that separates one lens from another. Every lens is engineered to have a specific focal length. This is the physical length of the lens. And a lenses’ focal length has a profound impact on what you will see through the lens. This is because focal length determines the lenses’ field of view. Field of view should not be a confusing concept to you because you live with a visual field of view all the time. Right now, your eyes are revealing a certain field of view to you. If you include the full periphery of your vision, you could say that your field of view is almost 180 degrees. But a lot of that, this stuff out here, is very indistinct. We think of the effective field of view of the human eye as narrower, somewhere around in here. Any lens that offers an equivalent field of view to this, is considered a normal lens. On a 35mm film camera, or full frame digital camera, a 50mm lens will be normal. On a camera with a smaller sensor, and it will be a shorter lens that is normal. A lens with a focal length that is shorter than a normal lens is considered wide-angle. With these lenses, you’ll see a much wider field of view than you will with a naked eye or with a normal lens. Lenses with a longer focal length, longer than normal are considered telephoto. A telephoto lens has a very narrow field of view but it also has a lot of magnification power. With it, you can enlarge distant objects. Now, some of these lenses are better for some applications than others. For example, if you were shooting sports, or wildlife, subjects which are usually pretty distant, you’ll want to use a telephoto lens. If you want to capture lots of details in a narrow space, then you’ll want a wide-angle lens. As you’ll see later, lens choice affects much more than field of view. You can dramatically change the sense of space and geometry in a scene, depending on the lens that you choose. The lens that came with your camera is probably a zoom lens. This is a lens that has a variable focal length. As you zoom out, you are shortening the focal length and going to a wider angle. As you zoom in, you’re lengthening the lens, narrowing its field of view, and magnifying your scene. Your cell phone camera most likely has a fixed-focus lens, what is sometimes called a prime lens. You can get either zoom or prime lenses for your SLR or mirrorless camera. Prime lenses, sometimes offer slightly better image quality and usually allow more flexibility in low light. You don’t need to worry too much about lens choice right now. The kit lens that came with your camera should offer a good range of everyday focal lengths. As you practice with it you’ll get a better idea of what types of focal lengths you’ll like to use, and when. With more experience, you’ll learn if and how, you want to expand your lens collection.

One of the great advantages of both SLR and mirrorless cameras is that you can take the lens off the camera and replace it with a different lens. This may sound strange, but shooting with different lenses will train your eye to see differently allowing you to see different kinds of subject matter. In other words, the ability to change lenses can greatly expand your creative repertoire. However, you can’t take any old lens and stick it on any camera that you choose. Lenses and camera bodies typically fit together as a system. Obviously, it’s a mechanical mechanism that allows the lens to attach to the camera body and different camera makers define their own proprietary mounting systems. These mounts do more than just provide a mechanical coupling – they also include electronics which let the camera and lens communicate with each other. This is necessary for things like auto-focus, lens stabilization, and other features. There are a lot of camera mounts out there. Canon has its own proprietary mounts for its SLRs as does Nikon, and Sony, and Olympus, and Pentax, and Fuji, and all of the others, and each of those companies makes a range of lenses. One of the things you’ll want to consider when shopping for an SLR or mirrorless camera is lens selection – what focal lengths are available, what level of quality and at what price. If you’re just starting out, you might not know what kind of lenses you might ultimately want. Perhaps the best choice, then, is to go with a system that offers the greatest variety. However, at the time of this shooting, most camera makers offer thorough, robust lens selections for their cameras, so don’t spend too much time worrying about lens availability. If you’re shopping for a mirrorless camera, then you should know that one mirrorless option is a standard called Micro Four Thirds. This is a camera mount and sensor specification that has been adopted by several companies including Panasonic and Olympus. Any Micro Four Thirds lens will work on any Micro Four Thirds body, so when shopping for a Micro Four Thirds camera, remember that there are many more options than just the ones provided by your specific camera vendor. There are several third-party companies that make lenses for a variety of camera systems. Tamron and Sigma are the best known and they will specifically state that a particular lens is Canon mount, or Nikon mount, or Fuji mount. They may even make separate versions of a lens for each different mount. Lenses are such a big topic that we have an entire foundations of photography course about them. Don’t go there yet, but you will want to take a look at it later as you continue your studies.

There was a time when the point-and-shoot was the most popular form of digital camera. Nowadays, point-and-shoots have lost ground to cell phone cameras, but there are still some out there and they still serve a purpose. For simple snapshots, a cellphone camera is probably a better option than a point-and-shoot simply because you most likely always have your cellphone with you. However, a decent point-and-shoot camera will still yield better image quality than the best cellphone camera. Unlike a cell phone, point-and-shoot cameras have zoom lenses, they might have more exposure control, and they most likely have a larger image sensor than a cellphone camera. The great advantage of a point-and-shoot over a mirrorless camera or SLR is size and portability. They pack small, they don’t weigh much; it makes them great for everything from backpacking and other forms of ultra-light travel to formal occassions where having a camera around your shoulder may not be appropriate. Some things to look for when you’re shopping for a point-and-shoot include sensor size. There are some point-and-shoots that have full frame image sensors, and the larger the sensor, the less noise the camera will produce in your images, especially in low light. You’ll also want to consider exposure controls. Some point-and-shoot cameras will include a full range of exposure controls, just like you’ll find on an SLR. If you like having a complete set of options when shooting, then you’re going to want those controls. Finally, you’ll want to consider price, size, weight and screen options. For example, do you want a screen that can be flipped around for selfies? A high-end point-and-shoot can be a very serious photographic tool. I will often carry one in place of an SLR or a mirrorless camera, and I’ve gotten some great images with this class of camera. However, at this point, the cellphone camera is the digital camera that most people have used and are still using. Fortunately, cellphone cameras today can deliver excellent image quality; sharp, good exposure, great color. But of course the biggest advantage of the cellphone camera over all other types of cameras is that you usually have your cellphone with you. Most people do not make their cellphone choice based on its camera’s capabilities, but if you do want to evaluate a cellphone camera, here are a couple things to look for. Things that cellphone cameras can have trouble with. Try pointing the cellphone camera at a scene with a wide-range of dark to light; a building against a bright sky. Can the phone show details in the building while preserving the color of the sky? Does it focus accurately? Shoot several portraits of someone, but frame the shot so that the person is in a different place each time. Does the camera keep them in focus? How quickly does it focus? Finally, does the camera offer any manual overrides for exposure and focus? Can you, for example, tap on the screen to focus on a particular point? Is there a way to dial the exposure up and down to brighten or darken a shot? Your cellphone can be a great, very usable camera, but it does have its limitations. And you’ll see what those are and begin to learn to work around those limitations as we progress through this course.

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