Camera and audio-video listings are full of abbreviations, and the same few terms come up again and again. This glossary explains 25 of them in plain language. The definitions are general and neutral, and they describe how each term is normally used rather than how any one brand uses it.
The ReviewExpo Editorial Team uses these terms across its buying guides, and they are listed in alphabetical order. If a term you met is missing, or an explanation seems wrong, email editorial@reviewexpo.com. You can also read how we work on the About Us page.
- Aperture
- Aperture is the opening in a lens that lets light reach the sensor. It is written as an f-number such as f/1.8, and a smaller number means a wider opening. A wider aperture lets in more light and gives a shallower depth of field.
- Aspect ratio
- Aspect ratio is the proportion of an image or screen’s width to its height. Common ratios include 3:2 for many still cameras and 16:9 for most video. It affects how a picture is framed and cropped.
- Bitrate
- Bitrate is the amount of data used per second of audio or video, often given in megabits per second. A higher bitrate can keep more detail but makes files larger. The same figure can look different between codecs.
- Bokeh
- Bokeh describes the look of the out-of-focus parts of a picture. It is shaped by the lens aperture, its design and the distance to the subject. People often use the word for the soft, rounded highlights in a blurred background.
- Codec
- A codec is a method for compressing and decompressing audio or video data. H.264 and H.265 are widely used video codecs. The codec affects file size, quality and which devices can play the file.
- Crop factor
- Crop factor compares a sensor’s size with a full-frame sensor. A sensor smaller than full frame has a crop factor above 1. It is used to work out the field of view a lens gives on that camera.
- Depth of field
- Depth of field is the range of distance in a scene that looks acceptably sharp. It depends on aperture, focal length and the distance to the subject. A shallow depth of field blurs more of the background.
- Dynamic range
- Dynamic range is the span between the darkest and brightest parts of a scene that a camera can capture with detail. It is commonly measured in stops. A wider range helps in scenes with strong shadows and highlights.
- Focal length
- Focal length is the distance, in millimeters, from a lens’s optical center to the sensor when focused at infinity. Shorter focal lengths give a wider view, and longer ones give a narrower, more magnified view. Zoom lenses cover a range of focal lengths.
- Frame rate
- Frame rate is the number of video frames recorded or shown per second, written as fps. Common rates are 24, 30 and 60 fps. Higher frame rates look smoother and allow slow motion when played back at a lower rate.
- Frequency response
- Frequency response shows the range of sound frequencies a microphone, speaker or headphone can reproduce, in hertz. It is often listed as a range such as 20 Hz to 20 kHz. The range alone does not describe how even or accurate the sound is.
- Full frame
- Full frame refers to a sensor about the size of a 35 mm film frame, roughly 36 by 24 millimeters. These sensors collect more light than smaller ones at the same resolution. Cameras with them are often larger and more expensive.
- HDMI
- HDMI stands for High-Definition Multimedia Interface. It carries digital video and audio over one cable between devices such as cameras, monitors and televisions. Different HDMI versions support different resolutions and refresh rates.
- Image stabilization
- Image stabilization reduces blur caused by camera shake. It can be built into the lens, the camera body or applied digitally. It helps most with handheld shooting and slower shutter speeds.
- ISO
- ISO is a setting that controls how sensitive the camera is to light. Higher values brighten an image in dim conditions but usually add visible noise. Low values give cleaner pictures when there is plenty of light.
- Lens mount
- A lens mount is the connection between a lens and a camera body. Each system has its own mount, so lenses are not always interchangeable between brands. Adapters exist for some combinations.
- Megapixel
- A megapixel is one million pixels, and it describes the resolution of a still image. More megapixels allow larger prints and more cropping room. Resolution is only one part of image quality.
- Microphone polar pattern
- A polar pattern describes the directions from which a microphone picks up sound. Cardioid microphones favor sound in front, while omnidirectional ones pick up sound from all around. The choice depends on the recording situation.
- Mirrorless camera
- A mirrorless camera has no mirror box and shows the image through an electronic viewfinder or screen. This design allows a more compact body than a typical DSLR. It still uses interchangeable lenses in most models.
- Phantom power
- Phantom power is a direct current supply, usually 48 volts, sent through an audio cable to power certain microphones. Condenser microphones commonly need it. Many mixers and audio interfaces can provide it.
- Resolution
- Resolution is the number of pixels in an image or on a display, such as 3840 by 2160 for 4K. More pixels can show finer detail. Sharpness also depends on the lens, the sensor and how the image is processed.
- Sample rate
- Sample rate is the number of times per second that audio is measured when it is digitized, given in hertz. Common rates are 44.1 kHz and 48 kHz. It works together with bit depth to describe digital audio quality.
- Sensor size
- Sensor size is the physical dimensions of the light-capturing chip in a camera. Common formats include full frame, APS-C and Micro Four Thirds. Larger sensors generally gather more light for the same field of view.
- Shutter speed
- Shutter speed is the length of time the sensor is exposed to light for one picture, usually shown as a fraction of a second. Fast speeds freeze motion, while slow speeds show blur. It is one of the three main exposure controls along with aperture and ISO.
- White balance
- White balance adjusts colors so that white objects look white under different light sources. Cameras offer automatic and preset modes, and many allow a custom setting. A wrong setting gives a blue or orange cast.