3. Parts of a Camera and how it works
The camera body is the main part of the camera system. Is it the part that everything else attaches or connects to. The lens is mounted on the front, the memory card and batteries are inserted and many cameras have a built in flash. External flashes can also be mounted on the body. The body is your main interface with the camera system.
The lens is one of the most important parts of a camera. This is where the light enters the camera and the photo begins. Lenses can come in various lengths (called focal lengths), apertures (how much light it lets in) as well as specialty lenses such as macro (close up), telephoto (for more reach), wide angle and more! Lenses can make a huge difference in how you take photos. The lens is often referred to as the "glass".
The viewfinder is where you look through the camera to see what the camera sees. This is your interface with the lens and camera. Most DSLR cameras have an Optical Viewfinder, which means you are looking through a prism and mirror to see what the lens is seeing. Optical Viewfinders are in line with the lens. A number of other camera information such as settings can also be viewed through the viewfinder to allow you to see what your camera is doing.
Some smaller cameras have a viewfinder off to the side of the body and not in line with the lens. These are called Electronic Viewfinders and they are actually a video display of what the camera is seeing.
The shutter blocks light from shining on the image sensor of the camera until you are ready to take a picture. When you click the shutter release, the mirror rises up, the shutter opens briefly, the image is captured and then a second shutter curtain closes. Once complete, the mirror comes back down in place. This is why you lose sight of your image briefly when you take a picture.
Some digital cameras now are "mirrorless" which means they don't have a mirror that raises up. Instead, the image sensor is directly behind the shutter and there is no mirror that has to be moved in order to capture an image.
The Shutter Release button is the button you use to actually take the picture. It controls the shutter automatically when depressed all the way down. Many cameras also use this button to activate the auto focus feature. When the auto focus feature is being used, you simply press the shutter release half way down to auto focus your photo. Then, to take a picture, continue to press the button all the way down to activate the shutter release.
Some photographers prefer to disable the auto focus feature of the shutter release and use one of the camera's auxiliary buttons to focus. This is helpful when taking photos of fast action such as sports or auto racing.
The LCD screen is found on the rear of the camera body and can be used to view photos taken as well as a "live view" of the viewfinder for taking photos. This screen is also the main display to view camera settings. This is where you interact with your camera to set it up, make adjustments and change settings.
Many DSLR cameras have a built in, pop-up flash that provides extra lighting in low light situations so you can take a photo. This flash works well with basic photos, however, pop-up flashes tend to be low powered and not adjustable so they can limit your ability to take longer focal length photos since they cannot cover a large area.
External flashes can be mounted on the camera's "hot shoe" bracket located near the pop up flash. These flashes are more powerful and can be adjusted for power, direction and intensity. They can also used away from the camera and remotely activated.
Camera Mode Dial
Nikon mode button
Canon mode button
The camera mode dial allows you to control how the camera takes a photo. The settings include an "auto" setting that allows the camera to determine what settings to use. While this is fine, it really limits your ability to control the photo and be creative.
The basic settings are:
Auto - the camera determines the settings
Manual (M) - you choose the aperture, shutter speed and ISO
Aperture (A or Av) - you set the aperture you want to shoot and the camera chooses all other settings.
Shutter (S or Tv) - you set the shutter speed and the camera chooses all other settings
Program (P) - the camera sets the shutter speed and aperature but you can adjust other settings. This is similar to Auto mode, but allows you more control and it can be very useful.
There are two articles below that explain the mode dial and program mode setting in more detail.
Image Sensor and Memory Card
The image sensor converts the optical image from the lens into an electronic signal. This signal is then sent to and stored on your memory card. The image sensor and memory card serve as the "film" for your camera. However, unlike old style film cameras, thousands of images can be stored on your camera at one time, depending on the size of your memory card. Once full, your memory card can be removed and another installed so you can keep taking photos.
Memory cards are used to store your photos as you take them. Memory cards range in size from a small (2 GB) to extra large (up to 2 TB). Most basic DSLR cameras use the "SD" or Secure Data style memory cards. In addition to storage capacity, memory cards are also rated for "speed". This speed can be how fast they can write (save) photos as they are taken or how fast they can read (retrieve) photos from the card.
SD style memory card
Exposure Compensation Button
This button allows you to adjust the exposure of your photo. You can make the image brighter or darker. The camera will adjust the other settings automatically. To learn more about exposure compensation, click here.
2a: Light Sources - Natural, Low Light & Artificial Light
Natural Light - (ambient/existing) - Provided by the sun, moon, etc. It is available outdoors and also indoors as is passes through windows/doors and illuminates a room
Low Light (such as at night) - in order to take photos in low light situations, you will need to use a larger aperature (smaller number), higher ISO and/or a slower shutter speed.
Artificial Light - use of a flash or other external lighting sources (street lights, room lights, directed light sources) can be a big help if you know how to use them. Using additional lighting in the daytime will reduce harsh shadows.