Glossary of Terms

Glossary of Terms

Digital SLR Camera (Single Lens Reflex)
Digital single-lens reflex cameras (also called digital SLR or DSLR) are digital cameras combining the optics and the mechanisms of a single-lens reflex camera with a digital imaging sensor, as opposed to photographic film. In the reflex design, light travels through the lens, then to a mirror that alternates to send the image to either the viewfinder or the image sensor. The viewfinder presents an image that will differ imperceptibly from what is captured by the camera's sensor.

DPI (Dots per inch)
DPI (dots per inch) is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm). Most printers print at approximately 300 DPI so a 2x6 print is 600x1800 pixels.

The term megapixel refers to the size of an image, usually in reference to a photo from a digital camera or camera phone. Megapixel means one million pixels. The resolution of digital cameras and camera phones is often measured in megapixels. For example, a two-megapixel camera can produce images with two million total pixels.

Print resolution
Print resolution is an objective measurement in relation to a printed photo or image, it refers to the average number of dots per square inch making up the print. The higher the dpi, the higher the amount of visual "information" in the print. As the average number of dots per square inch increases, color gradations will appear smoother and the edges of objects will appear sharper. Therefore, increasing print resolution results in finer detail becoming perceptible.

Screen resolution
The screen resolution also known as the display resolution of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an broad term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT), Flat panel display which includes Liquid crystal displays, or projection displays using fixed picture-element (pixel) arrays.

Extend vs. clone for a 2nd monitor
Setting a second monitor to extend will allow to completely separate screens allowing separate resolutions for each. Extend allows dragging items from one screen to the other. Setting the 2nd display to clone will duplicate the main monitor making both monitors look the same. If one is a lower resolution than the other both will be set to the lowest resolution. For this reason it is best to have both displays the same size and resolution when using clone.

Point and shoot camera
A point-and-shoot camera, also called a compact camera, is a still camera designed primarily for simple operation. Most use focus free lenses or autofocus for focusing, automatic systems for setting the exposure options, and have flash units built in. These are by far the best selling type of separate camera, as distinct from camera phones. They are popular with people who do not consider themselves photographers but want an easy to use camera for vacations, parties, reunions and other events.

Continuous light source (for photography)
Continuous lighting uses a constant light source to light your subject, meaning that your lights will stay on during the entirety of your photo shoot. This is often the lighting source of choice, as it offers easier anticipation of where light and shadow will appear in photos, is easier to setup (there is no triggering required by your camera), and is typically less expensive. The bulbs are cooler, meaning that your room should not get as warm as with traditional lighting. This lighting is good for tabletop photography, and a necessity with video.

Electronic flash (for photography)
An electronic flash is a camera accessory that provides a brief but powerful flash of light. It is an artificial light source produced by an electrical discharge traveling between two electrodes through a gas-filled tube. The light from electronic flash is approximately the same color as daylight.

Exposure mode (Program, Manual, Shutter priority, Aperture priority)
Exposure mode is how the camera adjusts the shutter speed and aperture to ensure the right amount of light reaches the film or CCD.

Program mode
Program mode has the camera calculate both shutter speed and aperture (given a manually or automatically selected ISO). Higher-end cameras offer partial manual control to shift away from the automatically calculated values (increasing aperture and decreasing shutter time or conversely).

Manual mode
Manual mode is both shutter speed and aperture and independently set manually (with ISO sensitivity also set manually), where proper image exposure requires accurate manual adjustment.

Shutter priority
Shutter priority or 'Time value' enables manual control of the shutter speed, and aperture is calculated by the camera for proper exposure (given an ISO sensitivity).

Aperture priority
Aperture priority or 'Aperture value' enables manual control of the aperture, and shutter speed is calculated by the camera for proper exposure (given an ISO sensitivity).

Shutter speed
In photography, shutter speed or exposure time is the length of time a camera’s shutter is open when taking a photograph. The amount of light that reaches the film or image sensor is proportional to the exposure time.

F-stop controls depth of field. Depth of field is the amount of area closer or further away from the camera that is in "acceptable" focus from the point that is in the sharpest focus.

If you wanted to make a photo with everything in focus from the closest object all the way to the horizon, then you'd need a very small f-stop. The higher the f-stop number, the smaller the opening and greater the depth of field.

ISO (with regards to photography)
ISO is measured in a scale (on standard digital cameras) called ISO. ISO is the number indicating a digital camera sensors sensitivity to light, the higher the sensitivity, the less light is needed to make an exposure. It is very helpful to be able to control ISO when taking pictures so you can ensure proper adjustment for desired picture quality. The higher the ISO number the quicker the sensor reacts to light – thus giving you effectively more light to use.

Serial port vs. USB port
A serial port is an analog communication port that appears similar to a VGA port but with 9 pins instead of the 15 a VGA port has. For a photo booth a serial port can be used for arcade style buttons. Serial ports were common years ago but are rare on modern computers. USB ports are a digital communication port that are more common today but will require a serial to USB adapter to use with arcade style buttons.

SRGB vs. Adobe RGB
These 2 are the most common types of color space used. Adobe RGB is more commonly used in a 4 color ink press where the sRGB is more common with desktop printers. For most booth applications sRGB is the best choice.

Chroma key (green/blue screen, with regards to photography)
Chroma key compositing, or chroma keying, is a special effects / post-production technique for compositing (layering) two images or video streams together based on color hues (chroma range). The technique has been used heavily in many fields to remove a background from the subject of a photo or video – particularly the newscasting, motion picture and videogame industries. A color range in the top layer is made transparent, revealing another image behind. The chroma keying technique is commonly used in video production and post-production.

White balance (with regards to photography: flash, florescent, tungsten, daylight, etc...)
White balance is essentially the concept of color temperature. Color temperature is a way of measuring the quality of a light source. It is based on the ratio of the amount of blue light to the amount of red light, and the green light is ignored. A light with higher color temperature has "more" blue lights than a light with lower color temperature. Thus, a cooler (resp., warmer) light has a higher (resp., lower) color temperature.

Graphic formats:

In computing, JPEG (seen most often with the .jpg extension) is a commonly used method of lossy compression for digital photography (i.e. images). The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality, and is the file type most often produced in digital photography or computer screenshots. The file type also is prone to pixelating when an image is shrunk.

TIFF (originally standing for Tagged Image File Format) is a file format for storing images, popular among graphic artists, the publishing industry, and both amateur and professional photographers in general. As of 2009, it is under the control of Adobe Systems. Originally created by the company Aldus for use with "desktop publishing", the TIFF format is widely supported by image-manipulation applications, by publishing and page layout applications, and by scanning, faxing, word processing, optical character recognition and other applications.

Portable Network Graphics (PNG) is a raster graphics file format that supports lossless data compression. PNG was created as an improved, non-patented replacement for Graphics Interchange Format (GIF), and is the most used lossless image compression format on the World Wide Web. PNG supports palette-based images, grayscale images, and full-color non-palette-based RGB[A] images.

.PSD is a Photoshop default file extension which stands for "Photoshop Document." A PSD file stores an image with support for most imaging options available in Photoshop. These include layers with masks, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings.

.AI  is an extension referring to an Adobe Illustrator file. If you are having a graphic designer create you vector art work like a logo design, you will need this file for future use. Of course, graphic designers will use Illustrators to create other graphic design pieces as well.