Aperture is a hole or an opening through which light travels. It is one of the basic parts of a camera, and its size determines how much light will reach the film or image sensor. The aperture also affects the depth of field, which is the zone of sharpest focus in an image. A large aperture (a low f-number) results in a shallow depth of field, while a small aperture (a high f-number) results in a deep depth of field.
Lenses are made from a variety of materials, each with its own set of properties that affect the way it bends and refracts light. The most common type of lens material is glass, but other materials such as plastic and quartz are also used.
The shape of a lens is also important in determining its focusing ability. Lenses are classified by their curvature into two types: convex and concave. Convex lenses have a curved outer surface that causes light to bend inward (toward the center of the lens), while concave lenses have a curved inner surface that causes light to bend outward (away from the center).
Lenses can be either positive or negative, depending on their overall effect on an image. Positive lenses magnify images, while negative lenses reduce them. Most camera lenses are designed to be either positive or negative; however, some special-purpose lenses, such as fisheye lenses, can produce both types of images.
The size of a camera lens is typically expressed in terms of its focal length, which is the distance from the lens to the sensor (or film) when the subject is in focus at infinity. The focal length determines how much an image will be magnified; shorter focal lengths produce larger images while longer focal lengths result in smaller ones
Shutter Release Button
Once all of the pixels have been charged, they are read out by the camera’s electronics and converted into a digital image file. The amount of time that the shutter remains open (shutter speed) determines how long light has time to enter the camera and strike the image sensor. A longer shutter speed will result in a brighter image, but will also increase the chance of blur if there is any movement during exposure (e.g., from wind or from shaking hands). A shorter shutter speed will result in a darker image, but will freeze any motion that occurred during exposure.
Memory cards come in different sizes, with the most popular being SD (secure digital) cards. SD cards can hold up to 2 GB (gigabytes) of data. Some newer types of memory cards can hold even more data. For example, an SDXC (extended capacity) card can hold up to 128 GB of information.
Most memory cards have a lock switch that prevents accidental deletion of files. Some also have a write-protect switch that prevents accidental overwriting of important files.
The viewfinder is the window on the camera that allows you to see what you are going to photograph. It also has important information such as the current aperture and shutter speed settings. The viewfinder can be either optical or electronic.