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In these lessons, you'll learn the basics of photography. No prior experience or equipment is required; you'll do everything right here in your browser.

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How does camera work?

The word “Photography" means "drawing with light".

Photo camera works in a similar way to how our vision works. Everything we see is a reflection of light. The camera is basically a dark box that captures light.

camera mechanism

Light goes into your camera through the lens. The lens glass focuses the light rays. The lens has an aperture - an opening that lets the light throught.

When you press a button on your camera you open a shutter, which is a gate that lets the light in for the time that it takes to take a picture.

Depending on whether you’re using a film or digital camera the light then exposes the film or a digital sensor and as a result you have captured an image.

Don't worry if you still don't fully understand. We're going to get into more details about each of the elements and learn how to use them.

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Shutter Speed

Shutter speed is the length of time the camera shutter is open, exposing light onto the camera sensor. A fast shutter speed means that the shutter is only open for a short period of time; a slow shutter speed means the shutter is open for longer.

Shutter speed ranges from the fastest 1/4000 second to the slowest 30 seconds. Among all, 1/2 to 1/1000 are more commonly used. Play around with shutter speed to see how it affects the image.

  • 1/2
  • 1/8
  • 1/30
  • 1/125
  • 1/500
  • 1/1000

The lower the shutter speed, the brighter the image. However, lower shutter causes motion blur so using tripod is recommended.

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Apperture

Aperture refers to the opening of a lens's diaphragm through which light passes. Aperture is expressed as an f-number (written as “f/” followed by a number), such as f/1.4, f/2, f/2.8, /f4, f/5.6, f/8, f/11, f/16, f/22, or f/32.

When changing aperture, you’re basically closing or opening the iris of your camera. Just like iris in your eye gets bigger in the dark and smaller when it’s bright.

Play around by changing the f-stop to see how it affects the image and the lens diaphragm!

  • f/1.4
  • f/2
  • f/2.8
  • f/4
  • f/5.6
  • f/8
  • f/11
  • f/16
  • f/22
  • f/32

The lower the f/stop, the larger the opening in the lens, and thus the brighter the image, and vise versa.

Hovewer, apperture also affects depth of field. We will discuss the depth of field more in another section. All you need to know for now is that the smaller the opening of the diagram is, the sharper your image will be.

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ISO

In traditional film photography ISO (or ASA) was the indication of how sensitive a film was to light. In digital photography ISO measures the sensitivity of the image sensor.

  • 100
  • 200
  • 400
  • 800
  • 1600
  • 3200

Higher ISO means the sensor is more sensitive to light which means the image will be brighter - this allows you to use your camera in darker situations. Hovewer, high ISO results in grain (noise) that may descrease the quality of an image.

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White Balance

In the very first class we mentioned that camera captures light. Different sources of light produce light of different shade of blue or yellow. Human eye adapts to different colors of light without us even noticing. Hovewer, in cameras it is controlled by a white balance setting.

The color of light, properly called color temperature is usually measured in Kalvin light temprerature scale from 1,000 to 10,000. The higher the Kelvin degrees, the colder the color temperature.

example of different white balance

Most artificial light bulbs produce warmer light (also known as Tungsten light). Sunlight in it's pure form has white color (also known as daylight). During a coudy day or in the shade, sun light has a blue tone. LED light bulbs come in a wide range of color temperature.

Play around with white balance setting on an image below, that was originally lit by bright daylight.

  • 3200K (tungsten)
  • 5000K (fluorescent)
  • 5600K (daylight)
  • 6500K (overcast)
  • 7000K (shade)

In most cameras, you could use an auto setting for white balance. Hovewer, it is important to understand whate balance because sometimes your scene will have different light sources.

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Exposure

Exposure is basically how bright or dark your image is. We call an image that’s too bright overexposed and the image that’s too dark underexposed. Sometimes, only parts of an image are underexposed or overexposed.

example of correctly exposed, underexposed and overexposed image

Aperture, shutter speed and ISO affect the exposure. They also affect other aspects of your image such and motion blur, grain and sharpness of the image.

example of low-key lighting when parts of the image are intentionally underexposed

Note that sometimes overexposing or underexposing parts of an image is an artistic choice. The photograph above is an example of what's called a low-key lighting: parts of an image are intentionally underexposed to enhance shadows and create a particular mood.

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Depth of Field

Depth of field is the area of the scene which appears well focused.

Note that “great depth of field” is only a term, it doesn’t at all mean that narrow depth of field is not that great. Depth of field can be an artistic choice that depends on what a photographer wants to convey.

For example, the image below has what’s called a great depth of field: everything from foreground to background is in focus (sharp).

example of great depth of field - everything is in focus

Second image has what’s called a shallow depth of field: the background and foreground are out of focus (blurry).

example of great depth of field - everything is in focus

Remember in a previous class we mentioned that lens aperture affects depth of field - the higher the f-stop the greater it is.

Another factor that affects depth of field is how far is the camera positioned from the subject. The further the camera is from the subject you’re photographing the greater the depth of field.

Third important factor that affects depth of field is focal length which we will discuss in the next sections.

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Focal Lenth

Focal length is the distance between the lens and a sensor, usually stated in millimeters (for example, 50mm). Some lenses have a fixed focal length - those are called Prime lenses. Zoom lenses have a range (for example, 24mm - 70mm) which allows you to change focal length by zooming in or out.

We call lenses with shorter focal lenth wide, and lenses with longer focal lenth long (or telephoto). Lenses with middle focal lenth are called normal.

Below are three lenses - wide, normal and long. Click on each one to see how differently they will capture the same scene.

  • Wide
  • Normal
  • Long

Normal lenses (usually around 50mm for most cameras) have an angle of view and perspective most similar to human eye. But let's discuss how wide and long lenses affect the image in more detail in the next two sections.

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Wide Lens

On a full-frame camera any lens with a focal length of 35mm or wider is considered a wide lens. On a crop sensor camera, wide angle lenses start at around 24mm. Lenses with 24mm or wider are called ultra-wide and lenses between 8mm and 15mm that create extreme hemispherical distortion are called “fisheye”.

example of an image captured with wide lens

Wide lenses have a very wide field of view so they are usually used to capture landscape, cityscape and architecture. Wide lenses have a great depth of field, which means usually everything from foreground to the background will be in focus.

example of an image captured with wide lens

Wide lenses are known to create an image distortion - objects that are located closer to the camera will appear much larger than objects further away. Because of this, wide lenses are not usually used to take portraits, unless photographer is intentionally going after the distortion effect as seen on an image above.

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Long Lens

Long lens, aka Telephoto is a lens with focal lenth of 120mm to 300mm and above. Long lens make objects appear closer to the camera in a way similar to a binocular. That's why usually your camera will need to be positioned further away from an object when you're using a long lens.

example of an image captured with long lens

Long lenses tend to have a shallow depth of field - only small fraction of an image will be in focus. The background will appear blurry.

Long lens will take longer time to focus and will usually require you to use a faster shutter speed. A good rule is to use a shutter speed 1/focal length of the lens. For example, for 600mm lens: a shutter speed of at least 1/600. Hovewer, you are welcome to experiment, especially if you're using a tripod.

example of an image captured with long lens

Tip: When shooting a portrait with long lens (just like any other lens) make sure to focus on the eyes of a person you're photographing. Eyes tend to be the first thing we look at on a photograph and when the depth of field is very shallow you want the eyes to be the most sharp part of an image.

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