Terminology

(For a complete list check out Forphotography Photography Terms)

AF (Autofocus) Lock

Used to prevent autofocus operation once the subject is in focus. This allows you to focus, compose, shoot.

Ambient Light

Ambient light is the amount of light that the camera sees before any supplemental light is added.

Aperture or F-stop

The scientific explanation is F-Stop = (diameter of the) aperture / focal length.  The simple explanation is how wide the opening is in the path from the front of the lens to the light sensitive material.

ASA

Abbreviation for American Standards Association. In conjunction with a number, e.g., ASA 400, refers to film "speed" or sensitivity. The higher the number, the more sensitive the film.

Backlit

A backlit subject is a subject where the dominate light source is behind the subject. When a subject is backlit you will likely loose detail in your subject. (See assignment flash)

Color Balance

All light sensitive material sees colors in a predetermined way.  Film is designed for a specific color balance and digital determines what it thinks the color is using software in the camera. The basic light types and how they relate to sunlight are: 
(See Color Balance Page for basic explanation)

Depth of field/focus

This is the area that is in focus.  In reality the area in focus extends in front of and behind the point of focus. Understanding how this works can be very vital in creating great images.

Low Depth of Field means that only a small portion of the picture will be in focus, and the remaining parts of the picture will be softly out-of-focus. When photographing people this helps draw attention back to the subject.

There are two main ways to obtain a narrow depth of field. Purchase a 50mm f1.8 lens, and set the lens to f1.8. You should always focus on the subject's eyes, and everything else should go out of focus. This effect is greatest when working closer to the subject.

If you are using a point and shoot camera simply set the camera to the PORTRAIT setting.

Digital Zoom

A feature that enlarges the subject within an image to fill more of the frame; using a digital zoom reduces the resolution of an image. Since all you are doing is zomming in digitally most experienced photographers will recommend turning this feature off. The image can be zoomed in later when you can decide if the loss of quality is worth the improved view.

Exposure

Admitting light into the body of a camera for a specific amount of time. With a digital camera, the light strikes an array of photosensitive receptors, which convert varying levels of light into electrical current.

Fast Lens

A mathematical formula applied to a digital image. Most image editors offer filters that can make dramatic changes

Filter

A mathematical formula applied to a digital image. Most image editors offer filters that can make dramatic changes in the appearance of a photograph.

FireWire (IEEE 1394)

Developed by Apple Computer, an IEEE 1394 standard-based interface that allows easy connection of one type of electronics device to another. It shares most of the features of USB, although it transfers data much faster.

Fixed Focus Lens/camera

A fixed focus lens/camera is a camera with no focus adjustment. This means that the camera has a preset area which is in focus. These cameras are often speciality cameras with specific uses. When using one like this you will want to know the limitations of the camera. For instance, if the lens area in focus does not include infinity don't shoot a mountain range.

Focal length

The distance between the surface of the camera lens and the sensor array at the back of the camera. The focal length of the camera determines how large the subject appears.

Formatting

Completely erasing and resetting a camera's memory card. This is usually done as a quick way to erase a full card that you want to reuse or to attempt to fix a card that can't be recognized by the digital camera.

Focusing

Adjusting a camera's lens system to bring the subject into sharp view.

Focus lock

Also called an infinity lock, this camera feature sets a camera to focus to a certain distance (ignoring closer objects, if present).

GIF

Graphics Interchange Format; a compressed image format. GIF was the first commonly used image format on the Web, but it has been largely replaced by JPEG.

Gigabyte (GB)

A unit of data equal to 1,024 megabytes.

ISO Film Speed

This is the setting of sensitivity to light.  The higher the number, the more sensitive to light to camera. However, there are drawbacks to higher film setting. These are noise on digital or grain on film.

Optical zoom

A feature that alters a camera's focal length, filling more of the frame with the subject.

Photography

Photography derives from the words writing with light. A photo depends upon exposure of a light sensitive material.  That material can be film or a light sensitive sensor.

Prime Lens

A prime lens is a non-zooming lens. For example, a 70-200 is a zoom lens while a 50mm is a prime lens. These lens are often less expensive and faster.

Shutter speed

All cameras have a shutter speed. It may be fixed, or adjustable, or automatic.  The shutter speed is how long the light sensitive material is exposed to the light.

Resolution

Think of this as how much information about the picture the camera records.  My recommendation is to always shoot at the highest resolution.  Resolution refers to how many dots, or pixels, are in a given amount of space. The higher an image’s resolution, meaning the more dots there are in the same amount of space, the less pixilation will occur, and the better the image will appear. Another way to understand this is to say that the more information that’s packed into an image, the smoother its appearance.

The resolution of an image on your computer screen is often measured by ppi (pixels per inch). A printed image’s resolution is often measured by dpi (dots per inch). An image that is 72dpi contains less information than one that is 300dpi. Images seen on a computer screen are usually 72 ppi, because 72ppi is what most monitors display, but 300dpi is the “industry standard” for photo quality printing. This leads us to the two different levels of resolution that a designer uses; screen resolution and print resolution.

JPG

This is the most common file format for the web.  JPG is a compressed format which means that you can lose picture quality when you save it.  It is sometime called lossy compression because it throws away image data to shrink a file.  Be very careful when saving pictures in this format.  (For a more involved discussion check out ForPhotography File Formats)

PPI/DPI

PPI and DPI are often used interchangeably.  Technically, that is incorrect.  DPI stands for Dots Per Inch and PPI stands for Pixels Per Inch.  A pixel is a digital point of light. (See PPI/DPI page)

White balance

Digital cameras have the ability to adjust the color based on the lighting situation where they are used. This is known as white balance. The cameras use white as a reference and adjust the color balance to give as true as possible a white, correcting all the other colors by doing this. HP color scientists have developed a family of algorithms to automatically adjust white balance under a wide range of conditions and with remarkable accuracy.

TWAIN

Technology Without An Interesting Name; the standard interface between software applications and image-capturing devices such as scanners.

USB

Universal Serial Bus; a popular interface for connecting all sorts of external devices, including digital cameras, to most PC and Apple Macintosh computers. A USB device can be plugged in and used without restarting a computer.

Zoom, optical

– A feature that alters a camera's focal length, filling more of the frame with the subject.

Zoom lens

A lens with an adjustable focal length that lets you see a scene from a narrow to a wide field of view.