B
B (Bulb)
The Bulb setting (abbreviated B) on camera shutters is a momentary-action mode that holds shutters open for as long as a photographer depresses the shutter-release button. The Bulb setting is distinct from the shutter’s Time(T) setting, which is an alternate-action mode where the shutter opens when the shutter-release button is pressed and released once and closes when the button is actuated again.
The bulb setting is used on some cameras, including some point-and-shoot cameras, to obtain shutter speeds slower than the minimum offered by the camera otherwise.
Because of the risk of camera movement, the camera is most often mounted on a tripod for the duration of the exposure. While it is generally possible to use the shutter release button on the camera itself, a cable release or electronic remote is often used to further eliminate the risk of shaking the camera during long exposures. The cable releases generally include a locking feature to eliminate the need to keep the button or plunger depressed during extremely long exposures.
The bulb setting is useful for the following types of photographic subjects:
- fireworks at night
- the night sky and celestial objects (see astrophotography)
- lightning
- streets at night (creating streaks from moving cars)
- light painting
Backlighting
An image is backlit when the light source is on the far side of the subject in relation to the camera. It means that there’s more light coming from behind the subject than is directly on the subject itself. It’s often used to separate the subject from the background to make a subject more dramatic, or to make a silhouette. In photography, a backlight (often the sun) that is about sixteen times more intense than the key light produces a silhouette. A fill flash used with a backlit subject yields more even lighting.
The vertical angle of the backlight can change the effect. A low angle can make the light hit the camera lens, causing a lens flare. A high angle can make the subject’s nose extend out from the mostly vertical shadow of the head, producing a potentially unwanted highlight in the middle of the face.
Backup
A copy of a digital file that’s kept in case of damage to, or loss of, the original digital image.
Ball head
A type of tripod head in which the head mount, which holds the camera, is attached to a ball-and-
socket joint. When the socket is tightened using the ball lock knob, it locks the head in place.
Barn doors
Four hinged doors fixed on the front of studio lights. The doors are used to modify the shape and the direction of the light.
Barrel distortion
Barrel distortion is a lens fault or aberration that causes straight, parallel lines in an image to bow outward, and is seen when shooting with wide-angle lenses. The wider the lens, the greater the distortion. The appearance is similar to the effect you’d see if an image was wrapped around a barrel. It can be corrected using post-capture software.
Beauty dish
A studio lighting device used to give a flattering effect in portrait and fashion photography. It consists of a large circular dish-shaped reflector, usually around 40-50cm in diameter, with a light source in the center. The light usually has an opaque cover so that only the diffused light reflected from the dish reaches the subject.
Beauty Dish example:
The difference when using:
Bellows
A concertinaed tube made of flexible, light-proof material that separates a lens from the camera body. Bellows were first used on very early cameras in the mid-19th century, and are still used on large-format equipment (such as the Ebony view cameras) today. They allow the plane of focus to be adjusted via a swing and tilt mechanism. Bellows are also used instead of extension rings on SLR cameras for making more finely adjustable macro images.
Bit
The basic unit from which any digital piece of data is made. Each bit has a value of either 0 or 1. The sizes of digital files are usually counted in bytes, which are each made up of eight bits. In digital photography, 0 is assigned to black and 1 to white.
Bit depth
The number of bits used to record the colour of a single pixel. Digital cameras usually use at least eight bits for each of the red, green, and blue channels, providing a 24-bit depth, and possible 16,700,000 colours. Many D-SLRs offer higher bit depths when setting to record in raw mode.
The examples below demonstrate the relationship between bit depth and image quality. We’ve taken a small detail of our favorite robot juggler illustration and exported it out at various color depths. The changes will be most obvious in the color gradations of the hat.
24-bit color: 224 = 16,777,216 colors, 45 KB
8-bit color: 28 = 256 colors, 17 KB
7-bit color: 27 = 128 colors, 13 KB
6-bit color: 26 = 64 colors, 10 KB
5-bit color: 25 = 32 colors, 8 KB
4-bit color: 24 = 16 colors, 6 KB
3-bit color: 23 = 8 colors, 5 KB
2-bit color: 22 = 4 colors, 4 KB
1-bit color: 21 = 2 colors, 3 KB
Sample graphic from FCIT’s collection of robot illustrations on the TIM website.
Blending mode
Blending modes determine how the pixels in a layer interact with the underlying pixels on other layers instead of simply covering them. Some blending modes are much more useful for photo editing than others. Multiply is used to darken an image, and Screen to lighten it; Overlay and Soft Light boost contrast.
Blown out
Bright areas in a photo that are over-exposed are said to be blown out. They won’t hold any detail and will be bleached white.
Bokeh
Derived from the Japanese word for ‘blur’, this term is used to describe the aesthetic quality of the blur in out-of-focus areas of a picture, or the lens creating them. Smooth, circular out-of-focus highlights are a feature of ‘good bokeh.’
Bounce flash
The indirect flash-lighting technique, where the flashgun is angled to bounce off a wall, ceiling, or another reflector. This scatters the illumination, creating a softer lighting effect.
Bounding box
In Photoshop, a rectangular border around a selected part of an image that can be dragged to transform, rotate, scale or move.
Bracketing
A system for increasing the chances of getting the correct exposure by taking a sequence of pictures with a slightly different exposure setting for each.
Bridge camera
A camera that bridges the gap between compacts and D-SLRs. They are similar in appearance and handling to small D-SLRs, but they have a fixed, usually ‘super zoom’ lens, with some models offering up to 50x optical zoom. Instead of a D-SLR’s optical viewfinder, they have an electronic viewfinder.
Brightness range
This is the difference between the brightness of the brightest part of the subject and the brightness of the darkest part of the subject. Also known as Subject Brightness
Range (SBR).
Buffer
Temporary memory used by a digital SLR. The size of the buffer in a camera helps dictate the maximum burst rate and the number of shots per burst.
Burn tool
A tool that can be used to darken parts of an image selectively during digital image manipulation. The tool gets its name (and its hand-shaped icon) from ‘burning- in’, a traditional darkroom process in which parts of a print could be made darker by giving some areas of a print more exposure than others. Also, see Dodge tool.
Burst rate
The continuous shooting speed of a digital camera, which enables a sequence of images to be taken in rapid succession, measured in frames per second (fps). The rate can only be sustained for a certain number of shots.
Butterfly lighting
A technique for lighting portraits achieved by pointing the flash down towards the front of the face and creating a distinctive butterfly-shaped shadow under the nose. A reflector is used to soften the shadow. This technique is also known as ‘Paramount lighting’ after the movie studio’s glamorous portraits from the 1930s.
Byte
The standard unit for measuring the memory capacity of digital storage devices. Each byte can have one of 256 different values and is equal to eight bits.
Sources: Pixabay, Wikipedia, Susan Wingfield Lamar High School
