Rossi FernandesJan 26, 2011 16:30:25 IST
If you're a complete novice when it comes to photography, but have a burning passion to learn and have no place to turn to when you're bombarded with jargon, we've got something for you. Here's a list of the most commonly used photography jargon simplified, so that anyone with even the most basic knowledge can understand them.
Artifacts are unwanted aberrations caused by sensor, optics or internal image processing algorithms of a camera. The most common artifacts are blooming, maze artifacts, chromatic aberrations, moire, jaggies, JPEG compression, noise, and sharpening halos.
Ever wondered why diagonal lines appear jagged rather than straight or smooth in some images? This is because of aliasing, which happens due to the square nature of pixels - the minutest component that any picture is made of.
Aperture / f-stop
When you click a photograph, the lens opens to certain degree so that light can pass through it and onto the camera's sensors or film. The size of this opening is referred to as the 'Aperture', and it directly effects the photo's 'exposure' and depth of field.
Aperture Priority (also known as Aperture Value and denoted by Av on the camera), is a mode where the photographer selects an aperture value and the camera decides the shutter speed according to lighting conditions, so that you get optimal results. It's different from 'manual mode' which allows you to set both aperture and shutter speed settings.
The aspect ratio of an image is the value of the width of an image/frame, divided by the height of it and denoted in the form of a ratio such as 16:9, 4:3 or 16:10.
Barrel Distortion is a common for of distortion in wide angle lenses where images tend to get 'spherized' or rounded towards the sides. Such distortion is more prominent in images which have many straight lines.
The "burst" or "continuous" mode allows you to take multiple shots one after the other. The number of shots taken are measured via fps or frames per second, and are different in different makes and models of cameras. To be a little more technical: the fps decides how many times the shutter releases and an image's processed in a second, defining how many pictures are taken in a short span of time.
Colour fringing is an aberrance caused by the lens used on cameras. It’s more visible on some cameras than others. It’s commonly seen as a blue or purple band lining a bright light source.
Depth of Field
The effect generated when the areas on the focal plane (at the focal length) of a camera in a photograph remains in focus (sharp), while other areas stay 'out of focus' (or blurry), is known as Depth of Field. It is enhanced by keeping the aperture small.
Unlike optical zoom (which uses a 'zoom lens' that alters its focal length to achieve the desired result), Digital Zoom re-sizes a part of an image digitally in order to fake actually zooming into it.
When photos are stored on digital cameras, a lot of additional details apart from the image itself are stored on the resulting file. This data (which is also called Metadata) is stored in the "header" of the file and may include everything from when the picture at hand was take (date, time), shutterspeed, aperture, ISO, and most other settings. This header is usually in the EXIF format (Exchangeable Image File), which was created by JEIDA (Japan Electronic Industry Development Association) as a universally accepted format so that all sorts of imaging devices could access it. This data can be used as a powerful learning tool since you can analyze shots taken by you, check the settings, and decide what settings work best for which type of shots.
The amount of light received by the film or sensor of a camera is known as exposure. The exposure of an image can be altered by changing the camera's aperture settings and shutter speed.
Even after selecting an aperture value and shutter speed to fit the lighting of a scene perfectly, an image may be underexposed. In this case the Exposure Compensation (or EV Compensation) found in prosumer and professional level cameras can be tweaked to fix the exposure.
The focal length of a camera (or an eye for that matter) defines the distance from the lens at which objects remain sharp or in focus. In other words, focal length is the distance (in millimeters - mm) between the optical centre of a lens and the focal point.
Full frame sensor
Sensors come in different sizes with point and shoot cameras having the smallest sensors and the larger and more expensive ones having much larger sensors. A full frame sensor is one which is the same size as a 35mm film. A large sensor helps in capturing much more detail and also can capture a much higher resolution image.
HDR is also known as high definition range imaging. HDR photographs are created by clicking the same image at different exposure levels and then merging them together using image manipulation software.
A histogram is a pictorial representation of the tonal distribution in an image. It shows the photographer whether a picture he's clicked has captured all the tonal details or its has areas that have been blown-out due to over-exposure.
Interpolation is a method used to increase the number of pixels in a digital image. It basically adds in extra pixels to increase the size of an image intelligently. While it's not as good as actually having an image of higher resolution, it's not as bad as just resizing an image without the addition of extra pixels.
ISO followed by a number (ISO 80, ISO 120, etc.) was used to denote the sensitivity level of camera film as specified by the International Standard Organization. The term 'ISO' stuck around for digital cameras too, where its used for the same purpose - i.e. to specify how sensitive your camera should be to incoming light. At higher ISO settings, your camera's sensor are more receptive towards incoming light, but this also adds more image 'Noise' than lower ISO settings.
A mode in a camera that's optimized for clicking picture of small objects from up close. This mode is usually denoted by the icon of a flower.
Metering is a technique used by cameras to measure the amount of light in a scene. Using this information, the camera can adjust the necessary parameters such as the aperture size, shutter speed and ISO depending on what mode it is on. Typically, you can set the metering modes to spot, center weighted or partial metering.
The unwanted grainy artifacts in the dark or uniformly colored areas of an image is called 'Noise'. In photographs, this happens due to the same pixels on the camera's sensor being exposed to different levels of light or different temperatures. Noise is considerably higher in images clicked with higher ISO (sensitivity) settings.
Photography filters are addons that can be attached to the front of a camera’s lens to enhance or to achieve a particular result. These are typically designed for DSLR cameras but some prosumer point and shoot models also have filters available for them.
Pincushion is the opposite of the barrel distortion, where an image gets pinched in the middle and lines around the sides curve inwards. This form of distortion is most common with zoom lenses.
RAW is an image format used by high end cameras - that unlike JPEGs - actually captures the 'raw', 'unprocessed', and 'uncompressed' data off the camera's sensors. It's the digital equivalent of the 'negative' image you get on film cameras, which means its the highest quality you'll get from a camera, hence its the most post-process friendly.
Just like the human eye, cameras have sensors which detect incoming light and are sensitive to the three primary colors - red, blue and green. Any color on the visual spectrum can be broken down to a mix of variable values of these three primary colors, and conversely these three colors can be used to form any color. Traditionally, cameras used film that had three seperate layers, each sensitive to a seperate primary color. In digital cameras however, the sensors percieve values digitally and convert them to a universally accepted file format such as JPEG or RAW.
Shutterspeed is the amount of time the mechanical shutter of a camera stays open, so that light can pass through it and on to the sensors or the film. The shutterspeed is measured in fractions of a second such as 1/2s, 1/4s, 1/8s, 1/15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s, 1/1000s, 1/2000s, 1/4000s, 1/8000s, which basically defines how long the shutter will stay open.
Like aperture priority, shutter priority is a mode in prosumer and professional level cameras where the user selects the shutterspeed and the camera decides the amount the aperture should open according to the scene at hand. This mode is ideal to capture moving objects where the photographer wishes to have one or more elements of a scene blurry.
Pretty much every 3D camera camera is a stereo camera, which means it has two separate lenses and most of the time two separate sensors.
The viewfinder is the "window" of a camera that allows you to look through it and preview what a picture would look like before you click it. The optical path of the viewfinder always runs parellel to the lens, so that you can see exactly how much of the scene you can capture in a still.
Another form of distortion found in Zoom lenses, Vignetting occurs when the barrel of the camera becomes visable in the corners of images.
Not all light sources that we perceive as 'white' are pure, since they have a certain color temperature that adds a yellow or blue tint to it. The human eye usually compensates for these color variations automatically, but digital cameras don't. In digital cameras, the white balance picks a shade in the image that's closest to white (indiscriminate of what tint it has) and balances the color palette of the image accordingly. So if the light source in the image has a slightly yellow, blue or any other tint, it might disrupt the entire color palette making it look warmer (more yellow-ish), cooler (more blue-ish), dull or more saturated than the actual scene.
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