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Understanding Your Camera

Understanding Your Camera

Understanding what is happening inside the camera when you press the shutter button can help you make better decisions when you take a photo. Remember that a camera simply records the light in a scene, or the light reflected off the subject. There is no other magic to it. Professional photographers love to say: “Photography is all about light, because without light, you have no photo.” However, without a camera you also have no photo.

BASIC PRINCIPLES OF THE CAMERA

The primary function of the camera is to capture the light reflected off the subject. That reflected light is actually what your picture is made of. The reflected light enters through the camera lens and exposes a light sensitive medium like a photographic film in the older film cameras, or an electronic sensor in digital cameras to capture the light and save it as an image.

The main parts of the camera involved in the process are the camera lens, the shutter, the image sensor and the memory to store the image. There are many working parts in a camera that contribute to producing an image. However, the functions of the other parts revolve around making sure the above mentioned parts are working properly together. The moment the image is captured, only two parts are involved: the lens and the image sensor. Therefore only the lens and the sensor eventually determine the quality of the image. All other functionality and controls built into the camera are there to make life easier for you, but they do not determine the quality of the photo. Therefore I think it is worth while to have a closer look at the lens and the image sensor.

IMAGE SENSORUnderstanding Camera - Sensor 1

The image sensor in digital cameras replaced the film in the older film cameras and converts the optical image to an electronic signal. CMOS and CCD are the two main types of sensors used in most digital cameras today.

The light coming through the lens is captured or read by the sensor and then processed and stored in the cameras memory. The sensor consists of a grid with millions of microscopic elements called photosites to capture the light information. Each of these photosites is better known as pixels, and there are one million pixels in a Megapixel.

SENSOR PIXELS

The earliest digital cameras had two or three megapixel sensors and were not sufficient for the demands of printing and viewing on high resolution monitors. It was necessary to develop sensors with more and more pixels, but how many pixels are too much? I think many manufacturers of small format cameras, and especially of smartphone cameras already crossed that line of too much pixels. Pixels just get smaller and smaller, and smaller pixels are less efficient than larger ones. The megapixel myth has treated camera manufacturers well over the years; those ever increasing, and often meaningless, numbers have sold millions of cameras. Larger pixels have a better dynamic range and can hold more light (info) in relation to the noise created by the pixels on the sensor, which means cleaner images. To compensate for noise, manufacturers of cameras with a large pixel count on a small sensor build noise reduction technology into the camera to cover up noise, but this is only attainable by compromising detail on the image. Larger pixels can contain more light, which means more information and gives a greater range of tonal values. A 16 Megapixel compact camera isn’t ever going have the picture quality of a 12 Megapixel full frame camera. What does matter is sensor size!

SENSOR SIZE

The size of sensor that a camera has ultimately determines how much light it uses to create an image. Bigger sensors have larger pixels and can gain much more information than smaller ones. Able to gain more information, they reproduce photos with better dynamic range, less noise, better colours, and much better low light performance, and can produce more detailed images.

Larger sensors mean larger cameras. Not only will the sensor take up more space in your camera, but it will also need a bigger lens to produce the larger image circle. This is why smartphone manufacturers generally stick with tiny sensors, they want to keep their devices light and slim and not deal with larger lenses. It also explains why professional photography gear is still so big and heavy.

Understanding Camera - Sensor 2

The image shows the different sizes sensors used in cameras today. Smartphone’s usually use the small sensor, while compact cameras sensor sizes range between the 1/1.7IN to the “Four thirds” sensors, and DSLR cameras sensor sizes range between the “ASP-C” and the “Full frame”.

To print an A4 size photo or view the photo on a 14″ screen, you have to enlarge the actual size of the light captured (sensor size) on a “Full frame” sensor 72 times, and on a 1/2.3IN” sensor you have to enlarge the image 2600 times. And we all know the more you enlarge an image, the more you sacrifice image quality.

A camera’s sensor is usually its most expensive component and this means cameras with larger sensors tend to be significantly more expensive than cameras with smaller sensors.

I would like to see camera and smartphone manufacturers be a bit more transparent about what size sensor is used and not hide it away on some spec sheet, to allow consumers to make an informed decision on what they are purchasing. As sensor technology improves, we’re seeing much better performance out of smaller sensors, but bigger will always be better!

SHUTTERUnderstanding Camera - Shutter

The shutter mechanism controls the length of time that the image sensor or film are exposed to the light, and is fitted right in front of the sensor/film. When the shutter release button is pressed, the shutter opens to allow the light to fall on the sensor/film. The shutter speed can be controlled and varied typically from 1/4000 seconds to 30 seconds, and on many cameras you can lock the shutter to stay open as long as you want. A higher shutter-speed allows the camera to freeze movements, and a slower shutter-speed may induce motion-blur in the scene. However, a lower shutter speed allows the image sensor to be exposed for a longer time period to the light reflected off the subject, which is especially great when photographing in low light conditions.

Many compact cameras (point-and-shoot cameras) use an electronic shutter that simply turns the image sensor on and off when needed. For example, if you select a shutter speed of 1/100 seconds, the image sensor will be turned on for a 1/100 of a second. SLR (Single-Lens Reflex) cameras usually use a mechanical shutter to control how long the pixels on an image sensor collect light.

CAMERA LENSUnderstanding Camera - Lens 1

Understanding camera lenses can help add more creative control to photography. The purpose of the camera lens is to focus and direct the incoming light rays to recreate the image as accurately as possible on the image sensor. The lens consist of one or more precisely shaped pieces of glass called elements, and a lens diaphragm (aperture) to control the amount of light that passes through the lens.

The lens is an extremely important part of the camera because the type of lens and the quality of the lens being used will contribute greatly to the sharpness and overall appearance of the picture. A good lens can easily cost more than the camera and it is important to get the lenses which suit your photography needs. On SLR cameras you usually buy the camera body separate from the lens.Understanding Camera - Lens 2

Which type of lens should you use?

There are so many lens choices on the market, which can make it overwhelming to try to figure out which ones are right for your photography needs. Apart from the overall quality of the lens, two specifications that are important when selecting a lens are the aperture and the focal length of the lens.

LENS APERTURE

Understanding Camera - Aperture 1Aperture is referred to the lens diaphragm opening inside the lens, which diameter can be changed to control the amount of light passing through the lens. While the shutter controls the length of time light is exposed to the image sensor/film, the aperture controls the amount of light that will reach the image sensor or film. Apertures are listed in terms of f-numbers or f-stops. Smaller f-number represents a wider aperture, and a larger f-number a smaller aperture. The larger the aperture, the more light the lens can let in. The aperture also determines the depth of field in a scene. A smaller aperture (larger f-number) gives a wider depth of field and a larger aperture (smaller f-number) gives a shallow depth of field. This is great for portraits to blur the background in order to isolate the subject from their background. When you invest in a Understanding Camera - Aperture 2lens it is important to look for a lens with a wide range of aperture settings as they provide greater artistic flexibility, in terms of both exposure options and depth of field. Lenses with a large aperture f-number start at f/1.0 to f/2.8. The smallest f-number is often referred to as the lens speed, because the shutter speed can be made faster for the same exposure. Lenses with larger maximum apertures also give faster and more accurate auto-focusing, especially in low light. Manual focusing is also easier because the image in the viewfinder has a narrower depth of field, making it more visible on the part of your subject that is the focus. The viewfinder on a digital SLR camera is also significantly brighter with lenses with larger apertures. These lenses are typically much larger, heavier and more expensive.

LENS FOCAL LENGTHUnderstanding Camera - Focal length

The focal length of a lens determines its angle of view, and thus how much the subject will be magnified. Perspective control can be a powerful compositional tool in photography, and often determines one’s choice in focal length.

There are two different types of lenses: Prime lenses (fixed focal length lenses) and zoom lenses. Often people get confused between a zoom lens and a telephoto lens. Zoom lenses have a barrel that extends to vary the focal length within a predefined range. You get wide-angle zoom lenses and telephoto zoom lenses. The primary advantage of a zoom lens is that it gives you more versatility on the focal length and can replace multiple prime lenses; however prime lenses generally have better optical quality. An inexpensive prime lens can generally provide similar image quality as a high-end zoom lens. Primary lenses are usually much faster (larger maximum aperture) than zoom lenses, and they are significantly smaller and lighter.

When I do macro photography, I believe in using a prime lens and in switching off all moving parts inside the lens like auto focus, stabiliser, etc., for sharper images and more accurate focus.

Wide-Angle lenses have a short focal length and capture wider views which makes them ideal for landscapes and architectural photography, where you often can’t move a long way away to fit large objects into the frame. On a full frame camera they range between a 20mm and 35mm lens.

Standard lenses have a focal length between 35mm and 70mm on a full frame camera, and gives a similar angle of view than the naked eye. In fact, a focal length of about 43mm gives the same view than the human eye.

Telephoto lenses have a longer focal length and capture enlarge views of the subject. They start at about 70mm and higher, however telephoto lenses are more often refer to as lenses from 135mm and higher.

Fisheye lenses are special types of ultra-wide angle lenses which can capture an extremely wide image, typically around 180 degrees. They have a focal length shorter than 20mm and show a distorted, spherical view most evident in the curved, outer corners of the photo, giving them a dynamic, abstract feel. They are also often use for artistic images.

Camera lenses’ focal length is based on full frame sensors (36mm x 24mm) which are the equivalent of the 35mm film cameras. Cameras with smaller sensors have what’s described as a crop factor. For example, a “Four Thirds” sensor (17,3mm x 13mm) has a crop factor of 2x, doubling the effective focal length of a mounted lens. When using a 50mm lens on a “Four Thirds” sensor will give a view similar to a 100mm lens on a “Full Frame” sensor which has no crop factor. That explains how smartphone manufacturers are able to keep their devices so slim and light, because they can use tiny lenses with a much wider angle which have a very small focal length. Most smartphones use a small 1/3.2 inch image sensor (4.54mm x 3.42mm) which has a large crop factor. Unfortunately small lenses means small apertures, and is the reason why smartphone cameras suffer in low light conditions. Small apertures results in the entire scene being in focus which is great, but it does not allow you to decrease the depth of field to isolate the object from their background.

WHICH CAMERA?

Often people ask me: “Why would I carry my large bulky camera with me while I also have a small compact camera?” And my answer is always, carry the “large bulky one”, because you can capture so much more information of your subject or scene. That special or great photo is almost never planned. You have a family barbeque and the perfect picture of your granddad sitting next to an open fire with the warm light of the fire highlighting the lines on his face appears right in front of you. And you have the opportunity to take one of your best photos, and the best photo ever taken from your granddad. Then you don’t want to sit with your compact camera on you chest which can’t handle low light conditions, or end up with a photo where the shadows are completely black. To switch on your camera flash will certainly spoil the photo and the moment, and it will just become another photo instead of a great portrait.

What camera should I buy? The one you can afford. Even if you have enough money to afford any camera, spending some of that money to help someone in need will give you much more satisfaction than the latest and greatest camera. The quality of the image will be determined by your camera, but a photo is created outside the camera. If you have an inexpensive camera, nothing stops you from still taking great photos. Whichever camera you buy will be able to take great photos and capture special moments. After all, most of the photos are not special because of the quality of the image, but it’s the moments you capture that make them special. Think of the old photos when you were a toddler, the low quality of the photos sometimes makes them even more special.

The type of photography is another factor to consider. If you are a professional photographer and need to take photos for billboards or large printed advertisements, you will surely need a full frame camera. But don’t let this article confuse you and feel your camera is not good enough.

These are just some general comments which are purely my own opinion on the subject. I really can’t give much guidance in a blog post to buy a camera. There are many other factors to consider and compare when buying a camera. The type of photography you are going to do will play a huge roll in your decision, e.g. if you are going to do sport photography, the shutter lag and the amount of focus points will be an important factor. There are great websites like http://www.dpreview.com/ which will give you up to date info and guidance of cameras currently on the market, and also allow you to do side-by-side camera comparisons.

In the next blog post I will discuss how to take control of your camera to take better photos.

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