Mid-term Quiz Review

Camera lens

A piece of curved glass that gathers light from the subject you are photographing, in order to focus that light on the film, and thus form an image. It controls the amount of light that reaches the film. It determines how much of the subject will be included in the picture and which parts of the subject will be in or out of focus.

Manual mode

Using your camera's manual settings allows you to have full control of all camera functions and thus the images you are making.

Overexposed image

An image that is too bright because the sensor was exposed to too much light for a correct exposure.

Underexposed

An image that is too dark because the sensor was not exposed to enough light for a correct exposure.

Aperture

An opening created by a series of overlapping blades located in the lens through which light passes to enter the camera. You can open it up to allow more light in, or close it down to reduce the amount of light that passes through and reaches the sensor/film. It is an easy concept to understand if you just think about how your eyes work. As you move between bright and dark environments, the iris in your eyes either expands or shrinks, controlling the size of your pupil. In photography, the "pupil" of your lens is called aperture. You can shrink or enlarge the size of the aperture to allow more or less light to reach your camera sensor.

Camera Obscura

Darkened, room size chamber, in which a tiny opening in one wall acted like a lens, focusing an upside-down image of the scene outside onto the opposite wall.

Depth of field

Depth of field is the amount of your photograph that appears sharp from front to back. Some images have a "shallow" depth of field, where the background is completely out of focus. Other images have a "deep" depth of field, where both the foreground and background are sharp. DOF is controlled by: lens aperture, distance to subject and lens focal length. The primary control of depth of field is the f-stop setting. The smaller the lens aperture (bigger #) the greater the depth of field. The larger the lens aperture (smaller #) the less depth of field you will have. Thus if you set your lens at f/16, you will produce an image with far greater depth of field than if you set the lens at f/2.

Equivalent exposures

Different combinations of shutter speed and aperture that are equal and result in the same exposure.

Camera exposure

Exposure refers to the amount of light that strikes the film/sensor when you press the shutter button to take a picture.

Camera Focus

Focusing is the moving of the lens elements until the sharpest possible image is achieved.

ISO

ISO is your camera's sensitivity to light. ISO is displayed in a number like this: 100, 200, or 400. Essentially, when you adjust your ISO, you're changing your camera's sensitivity to light (i.e., you brighten or darken your image). The ISO is how you can adjust the exposure on your camera. It's one of the three main pillars of exposure — along with shutter speed and aperture. Changing the ISO will brighten or darken your image. When it comes to measuring the ISO, the lower the ISO, the darker your image will be; the higher the ISO, the brighter your image will be.

Noise

In digital photographs, "noise" is the commonly-used term to describe visual distortion. High ISOs typically have a lot of noise (digital) and grain (film) associated with them because it makes the camera sensor absorb light faster. That means, the higher the ISO, the harder the image sensor is working to produce a good image, which sometimes produces more digital noise or grain.

F-stop

Lens aperture refers to the physical lens opening and f-stops are a way of describing the size of the aperture The f-stop numbers are counterintuitive. Higher number=smaller lens opening (less light passes through). Lower number=larger lens opening and (more light passing through). A lens set at f/16, for example, allows much less light to pass through than a lens set at f/2. When you change from one whole f-stop to another, you let in half or twice as much light, depending on whether you make the opening smaller or larger.

Camera shake

Movement of a camera when the exposure is being made that results in a blurred or unsharp image, especially at slow shutter speeds. Do not handhold your camera and take a picture at the speed 1/60 and lower.

Simultaneous Invention

Photography has been invented by several people. Photography does not have a linear chronology and instead suggests that there may have been other successful yet unknown attempts to invent photography. From 1839 twenty-four people had claimed to have invented photography.

Correct exposure

The act of having correct exposure means your combination of settings between aperture, shutter speed and ISO speed have produced a perfectly exposed image.

Shutter Speed

The camera shutter is a curtain (or a set of blades) that blocks light from entering and striking the film. The camera shutter must open to make an exposure and the amount of time that the shutter is open is referred to as shutter speed. Shutter speed determines the appearance of motion or movement (whether a moving subject looks sharp or blurred). A fast shutter speed (125, 250, 500, 1000) will freeze motion (to varying degrees), slow speeds (30, 15, 8, 4, 2, B) will allow for motion blur (to varying degrees). Shutter speed also has stops. Each stop is either twice as long or half as much time.

Histogram

The histogram is a visual display of the tones in your image. The histogram shows you more information about the image than you can see with your eyes.

Plane of critical focus

The plane of critical focus is an imaginary two-dimensional plane that "slices" through your scene. Everything lying on that plane is in focus, and objects in front or in back of it are out of focus, to various degrees depending on the camera and optics.

photography

The recording of light which translates a 3 dimensional space into a 2 dimensional space.