Camera:
Lens
The lens is one of the most vital parts of a camera. The light enters through the lens, and this is where the photo process begins. Lenses can be either fixed permanently to the body or interchangeable. They can also vary in focal length, aperture, and other details.
Viewfinder
The viewfinder can be found on all DSLRs and some models of digital compacts. On DSLRs, it will be the main visual source for image-taking, but many of today’s digital compacts have replaced the typical viewfinder with an LCD screen.
Body
The body is the main portion of the camera, and bodies can be a number of different shapes and sizes. DSLRs tend to be larger bodied and a bit heavier, while there are other consumer cameras that are a conveniently smaller size and even able to fit into a pocket.
Shutter Release
The shutter release button is the mechanism that “releases” the shutter and therefore enables the ability to capture the image. The length of time the shutter is left open or “exposed” is determined by the shutter speed.
Aperture
The aperture affects the image’s exposure by changing the diameter of the lens opening, which controls the amount of light reaching the image sensor. Some digital compacts will have a fixed aperture lens, but most of today’s compact cameras have at least a small aperture range. This range will be expressed in f/stops. For DSLRs, the lens will vary on f/stop limits, but it is usually easily defined by reading the side of the lens. There will be a set of numbers stating the f/stop or f/stop range, ex: f/2.8 or f/3.5-5.6. This will be your lowest settings available with that lens.
Image Sensor
The image sensor converts the optical image to an electronic signal, which is then sent to your memory card. There are two main types of image sensors that are used in most digital cameras: CMOS and CCD. Both forms of the sensor accomplish the same task, but each has a different method of performance.
Memory Card
The memory card stores all of the image information, and they range in size and speed capacity. The main types of memory cards available are CF and SD cards, and cameras vary on which type that they require.
LCD Screen
The LCD screen is found on the back of the body and can vary in size. On digital compact cameras, the LCD has typically begun to replace the viewfinder completely. On DSLRs, the LCD is mainly for viewing photos after shooting, but some cameras do have a “live mode” as well.
Flash
The on-board flash will be available on all cameras except some professional grade DSLRs. It can sometimes be useful to provide a bit of extra light during dim, low light situations.

User Controls
The controls on each camera will vary depending on the model and type. Your basic digital compacts may only have auto settings that can be used for different environments, while a DSLR will have numerous controls for auto and manual shooting along with custom settings.
Lens:
A lens with a rounder shape will have a more acute bending angle. Curving the lens out increases the distance between different points on the lens. This increases the amount of time that one part of the light wave is moving faster than another part, so the light makes a sharper turn.
Increasing the bending angle has an obvious effect. Light beams from a particular point will converge at a point closer to the lens. In a lens with a flatter shape, light beams will not turn as sharply. Consequently, the light beams will converge farther away from the lens. The focused real image forms farther away from the lens when the lens has a flatter surface.
Increasing the distance between the lens and the real image actually increases the total size of the