Commercial Photography Glossary of Terms
Aperture – A variable opening in the lens that controls the amount of light let into the camera and onto the sensor.
Aperture priority – An exposure function where the user controls the aperture and therefore the depth of field and the camera alters the metering and shutter speed accordingly.
Anti-aliasing – Smoothing the jagged edges (aliasing) of selection or paint tools in digital imaging software.
Artifact – A defect or flaw in a digital image.
Bit – A binary digit. A digital quantity representing either 1 or 0.
Bitmap – An image made up of dots or pixels. All cameras produce these.
Buffer – This is the memory that can store images before they are written to the memory card. This means a burst of photos can be taken in a short space of time.
Burst mode (Continuous Shooting) – This lets you take several pictures quickly in succession until you take your finger off the shutter button, useful when you want to take pictures of fast-moving action eg sporting commercial photography
Camera Shake – Blurring in an image caused by movement during an exposure – avoided by increasing the shutter speed, using flash or a tripod.
CCD – (Charge-Coupled Device) Converts light into electrical current. This is the image sensor which is the digital equivalent of film.
Cloning – A feature in image editing software that allows one part of the image to be duplicated over another. This allows blemishes or artifacts to be seamlessly removed.
CMOS – Complementary Metal-Oxide Semiconductor. This is an alternative image sensor to the CCD.
CMY, CMYK – (Cyan, Magenta, Yellow) Color printing model. CMYK adds black (Key) and is used for most professional printing applications.
CompactFlash – Type of removable digital data storage media used in DSLRs – generally used in commercial photography
Depth of Field – The area in front and behind the focus point that is sharp. This is controlled by the aperture. For a more thorough explanation see our Photography Technique – Depth of Field article.
Digital single lens reflex (DSLR) – Digital single lens reflex cameras let you change the lens to suit the type of picture you’re taking. You can use the starter lens that comes with the camera for everyday pictures and buy additional lenses for varied conditions or styles or commercial photography specializations.
Digital Zoom – A feature that enlarges the central part of the image to create the effect of a telephoto lens. It is in fact just cropping the image.
DPI – (Dots per Inch) – Is a measurement of the resolution of a printer or monitor.
Electronic Viewfinder – A tiny LCD screen mounted inside a viewfinder to replace an optical system.
Exposure – The amount of light falling on a CCD or image sensor. It is controlled by a combination of shutter speed and aperture.
Exposure Bracketing – This feature causes the camera to take a series of differently exposed shots with one press of the button. With any luck one of the shots will be perfectly exposed. Or you can take a number of both darker (underexposed) and lighter (overexposed) images and combine them using photo editing software such as Photoshop’s HDR feature to produce an image with correctly exposed shadow, depth and highlight elements. HDR is becoming an established post shoot activity in commercial photography.
EXIF (Exchangeable Image Format) – enables information such as the time and date of the photograph be stored alongside the exposure.
EV Compensation (Exposure Value Compensation) – This is a feature that will let you override the camera settings to lighten or darken your image.
f-Number / f-stop – The f-number describes the diameter of the aperture as a fraction of the focal length of the lens. The smaller the f/number the larger the aperture and the greater the potential light entering the camera and reaching the sensor and the shallower the depth of field.
Focal Length – The measurement that determine the magnification and field of view of a lens. Expressed in mm.
Hot shoe – This small attachment at the top of some cameras for adding an external flash – vital for illuminating subjects more than a few metres away.
Infinity -The farthest possible distance a lens can focus on.
Interpolation – Increasing the number of pixels in an image or filling in missing colour information by sampling neighbouring pixels. This cannot add information or detail to the image.
ISO – (International Standard Organization)– This used to refer to the light sensitivity of film. So in digital terms it relates to the sensitivity of the sensor. The darker a scene then a higher ISO will be needed. The higher the ISO number, helps to achieve blur-free, pictures without flash. You have the option to set it manually on some cameras. However, the higher you set the ISO, the more ‘noise’ you get in your photos – something that is to be avoided in most areas of commercial photography. For a more thorough explanation of ISO Sensitivity see our Photography Technique – ISO Sensitivity article.
JPEG (Joint Photographic Experts Group) – compressed image file format. JPEG allows a large amount of information to be compressed to take up less memory. Virtually all cameras use this format. For commercial photography, many photographers shoot in RAW format and then adjust the images post shoot to produce TIFF and JPEG images.
Macro – Used to describe photographs that are very close-up but refers to a lens that can focus at close distances, usually less than 30cm. Often indicated by an icon of a flower on camera controls, macro mode helps you take highly detailed close-ups.
Manual – The function where the user enters all the variables that make up the exposure, the shutter speed and exposure settings must be entered manually.
Memory Card – A form of removable storage, which stores all the information for each photograph. They come in a variety of formats (SD card, Smart Media, CompactFlash, Sony Memory Stick)
Megapixel – A measurement of camera resolution. One million pixels is a megapixel. 5Mp is 5 million pixels, for example. More pixels means more detail in the picture taken, which will allow you to create larger prints.
Noise – In digital cameras noise often occurs in low light images or where high ISO values have been used. It shows in the form of pixels that have random colours on dark areas of the image.
Pixel (PICture ELement) – The smallest element of a picture. All digital photos are made of small squares or pixels.
PPI – (Pixels/Points Per Inch) – A measurement of resolution in scanners, images and printers.
Programmed Auto Exposure – This is the fully automatic option where the camera chooses the aperture and shutter speed for you.
RAW – Unprocessed image files
Red-eye reduction – In poor light the pupil of the eye opens wide to allow more light to get to the retina. But this means, when the flash goes off, some of the light is reflected back and gives the appearance of red eyes. When you use red-eye reduction, the flash goes off before the photo is taken so the subject’s pupils have time to narrow and less light is reflected back from the retina.
Resolution – Measurement of the amount of information in an image in the form of pixels. Often expressed as two figures representing the image width and height, such as 2272 X 1704 pixels for 4 Megapixels or 5616 x 3744 pixels in the 22 megapixel images produced by the Canon 1Ds Mk3 used in commercial photography.
RGB (Red, Green, Blue) – Digital Cameras use a mix of R, G and B to make up the colors of an image.
Scene Modes – Scene modes are so common on digital cameras that they are almost de rigueur nowadays. They usually have names like “Snow”, “Portrait”, and “Sport”. They are really just automatic aperture and shutter settings that are designed to give optimum results in tricky lighting conditions (like bright ski slopes) or when taking action shots (like racing cars.) Some cameras have a huge number of scene modes, so there shouldn’t be a lighting situation that the manufacturer hasn’t thought of.
Shutter Lag – The delay between the pressing of the shutter button and the picture being taken – this is becoming less noticeable with recent, more advanced cameras.
Shutter Speed – The time in which the image sensor or CCD is exposed during the exposure.
Shutter speed priority mode – This is the opposite of Aperture Priority, so you set the shutter speed and the camera chooses the aperture. This a good for fast moving objects. This feature is ideal for Saturday morning football when you want to capture fast-moving action or deliberately blur an image to show movement. A shutter speed of 1/500 will give you a crisp shot of that penalty while 1/30 will show the ball moving in a blur.
SD – Secure Digital image storage card
Telephoto – A lens that magnifies the subject making it seem closer.
TIFF (Tagged Image File Format) – an uncompressed image file format
USB (Universal Serial Bus) – USB cables are used for transferring images between electronic devices including cameras and PC’s and Mac’s.
White Balance – Color has a temperature and all whites vary slightly. White balance presets on some cameras allow you to take photos in different types of light i.e. tungsten, fluorescent and sunlight without any color casts. White Balance controls are used to find the most neutral white – see the Photography Technique – White Balance article for further information. For a more thorough explanation see our Photography Technique – White Balance article.
WiFi – Wireless Fidelity used as a wireless communications environment within which WiFi equipped electronic devices can communicate with each other. Most popularly used for linking electronic communications devices with to an internet connection.