In every art practice, there is a language built around its theory and mechanism. This ever-expanding glossary outlines some key terms used in photography.
Also known as available light, ambient light is any light that isn't deliberately set up by the photographer. This includes both natural or artificial lighting.
The opening of a lens diaphragm through which light passes. Aperture dictates the brightness/darkness and overall depth of field (DoF) in an image. A larger aperture opening permits more light but renders less depth of field (less in focus). A smaller aperture reduces the light reaching the sensor but allows for more depth of field (more in focus).
An aperture with a smaller opening is signalled by a larger f-number. An aperture with a larger opening is designated a smaller f-number. So an aperture of f/2.8 is physically larger than the opening in an aperture of f/16.
Aperture priority, frequently abbreviated A or Av is a mode on some cameras that allows a photographer to set a specific aperture value (f-number) while the camera automatically selects a shutter speed to make an appropriate exposure.
Auto (Automatic) mode
Auto mode or Automatic mode is a setting that allows a camera to automatically set the shutter speed, aperture, and ISO for each exposure.
Blue Hour occurs during twilight (in the morning or evening) when the Sun has completely dissapeared about 4 to 6 degrees below the horizon. At this time, the remaining sunlight takes on a predominantly blue hue. This time of day is particularly favoured by artists and photographers who seek out the tranquil quality of the light. Blue hour is an aesthetically atmospheric period and can be favourable for shooting portraiture as well as architectural and landscape subjects.
Bokeh is a Japanese word which translates to haze or blur . Bokeh is defined as the way a lens renders unfocused points of light. Depending on inherent aberrations and shape of the lens diaphragm, the out-of-focus quality renders differently. Photographers often employ a shallow depth of field to create images with prominent out-of-focus regions, coaxing out the bokeh effect.
Often used in star-trail photography, Bulb mode is a setting on a camera that holds the shutter open for as long as a photographer holds the shutter-release button down. Bulb also works with the use of a shutter release cable/remote.
Camera shake is caused by the physical movements made by a photographer or camera. During longer exposures, camera shake can manifest in blurry photographs. Using a tripod or a monopod, setting a faster shutter speed and utilizing a remote shutter trigger will help reduce or stop the effects of camera shake.
Another method used by photographers to steady a camera is to stop the shutter speed from dipping below the focal length of the lens. In addition, holding the camera with both hands, with elbows tucked close to the body can reduce camera shake. Some photographers even suggest taking a deep breath and holding it while making an exposure in this position.
Camera shake can also be caused by the internal mechanisms of the camera moving during an exposure. Also known as mirror slap, this type of camera shake can be reduced by using Live View Mode. Some cameras also have Mirror Lock-up mode which allows a photographer to press the shutter button once to open the mirror mechanism, and then a second time to shoot the exposure. Mirror slap is not an issue in mirrorless cameras, because they function without the use of a mirror.
Camera Shake Reduction
Camera Shake Reduction is an algorithm used in Photoshop that is capable of detecting the path of a camera's movement through a shake, compressing the path into a less-blurred image.
Car trail photography is a type of light trail photography made during long exposures in darker environments, with an ND filter or in the evening/night/early morning. In car trail photography, the photographer sets the camera for a long exposure near a busy roadway. The resulting photographs exhibit the bright streaks of light caused by the head and tail lights of travelling cars.
A chemigram is an intersection of painting and photographic chemistry. The experimental technique involves applying a substance or resist to a sheet of photographic paper and subsequently immersing the paper in developer and/or fixer. The resist repels and interacts with the darkroom chemistry, causing unique and abstracted manifestations. Not to be confused with the Chemogram.
Chemograms are made by partially processing an enlarged image on photographic paper in the darkroom. When sufficiently developed, the paper is then exposed to light and selectively painted over with developer, fixer and other chemicals. This differs from the chemigram process in that chemigrams are made under consistently well-lit conditions with a substance applied directly to a sheet of photographic paper before development.
Depth of field (DoF)
Depth of field refers to the distance between the nearest and the furthest points in an image that are in focus. DoF describes the level of blurriness or sharpness around a subject. For example, a shallow depth of field is a small area of focus.
Digital Single Lens Reflex (DSLR)
A digital single-lens reflex camera (DSLR) is a digital camera that uses a mirror and prism system that allows a user to see a composition live through the viewfinder before the image is made. When the shutter button is pressed on a DSLR camera, the mirror component flips up, permitting light to pass through to the sensor to record an exposure. This is in contrast to a mirrorless camera system, which completely removes the complex network of mirrors found in the SLR or DSLR camera.
Dragging the shutter (shutter drag)
Shutter drag involves using a slower shutter speed in conjunction with a flash. In an environment with little light, the flash exposes the immediate subject, while the shutter continues dragging more detail out of ambient light.
Exposure describes the amount of light that reaches the camera sensor or film. Exposure is a term that is also used to describe the action of taking a photograph, eg. the photographer made an exposure.
A flash is a device used in photography to produce a brief burst of light to illuminate a dark scene and freeze moving subjects. Battery-operated speedlights are attached to a camera, providing the ability to comfortably handhold the camera while achieving a more balanced exposure. Battery or mains-powered monolights are more powerful than speedlights but are less portable and a pack-and-head system is the bulkiest flash option, but they are the most powerful and offer the fastest recycle speeds.
Flash Sync Speed
Flash synchronization or flash sync is the synchronization of a flash with the opening of the shutter during exposure. Flash sync speed represents the fastest shutter speed a camera and flash can synchronize. Usually, the sync speed is from 1/200s to 1/250s. If a flash sync speed is 1/250s and a photographer shoots at a faster shutter speed while using a flash, the shutter closes before the flash can be fully captured by the sensor, resulting in black bands in the image.
Focal length measures the distance between the optical centre of the lens and the camera’s sensor (or film plane) in millimetres with the camera focused to infinity. Lenses are named by their focal length, and you can read this information on the exterior of the lens barrel.
Freeze (frozen motion)
Frozen motion is achieved when the shutter speed of the camera is high enough to catch a sharp rendering of motion occurring in a scene. The result is a subject that appears to be frozen in time with little-to-no motion blur.
An f-stop or f-number is a camera setting that indicates the aperture of a lens. While f-stops aren't uniform across all photography equipment, there are common values that make up the standard aperture scale:
On a DSLR, these values can be seen in-camera through the viewfinder and on the LCD screens. The f-stop value can be altered directly in Manual mode and Aperture Priority mode. The larger the value of the f-stop number’s denominator, the less light will enter the lens and the more depth of field is generated.
HSS (High-Speed Sync)
HSS synchronizes flash pulses to the movement of a camera shutter, allowing for shutter speeds up to 1/8000 second. Without a HSS system, photographers can only sync with flash up to a shutter speed of 1/250s.
ICM (Intentional Camera Movement)
Intentional Camera Movement (ICM) is a photographic technique that involves purposely moving the camera over a long exposure. The results are dynamic, abstract renderings of an environment and lighting conditions.
ISO first referred to the sensitivity of film to light. The higher the ISO, the greater the sensitivity of the film. For digital photography, ISO refers to the signal gain of the camera's sensor, producing more brightness when set to a higher ISO value. However, the higher the ISO, the greater the digital noise in a photograph.
Light painting is a photographic technique employed to illuminate a subject or space or to draw by moving an object emitting light during a long exposure. Man Ray, Barbara Morgan and Pablo Picasso all used various light painting techniques to create painterly photographic renderings of light.
Light painting requires a slow shutter speed, usually at least one-second in duration. During an exposure, a subject moves a light source, creating paths of light that are traced out in the exposure.
Macro photography is a field of photography that produces photographs of small subjects at larger-than-life sizes. Macro photographers often use specialised equipment to capture subjects at a level of detail that is usually missed by the naked eye.
Manual mode is a mode on the camera that allows for full manual control of both Aperture and Shutter Speed. In this mode, the aperture and the shutter can be set to any value, granting a photographer greater command over an exposure in any scenario.
A mirrorless camera is a digital photographic camera that forgoes the complex mirror network of DSLR cameras. In a mirrorless camera, the light entering the lens continuously reaches the image sensor. Because light is not reflected through an optical viewfinder mechanism, mirrorless cameras rely on electronic viewfinders and LCD screens to project a live rendering of a scene or subject.
Without a mirror mechanism, mirrorless cameras can be manufactured more simply, with less bulk than DSLR cameras. Mirrorless cameras are also quieter than DSLRs and the electronic viewfinder can support a live depth of field preview and render subjects in the correct exposure in real-time.
Mirror Lock-up (MLU)
Mirror lock-up is a feature in-camera that allows a photographer to reduce vibrations caused by the mirror during exposure. A normal exposure in an SLR or DSLR camera sees the mirror flip up into the mirror box to let light make contact with the camera sensor or film. However, this motion can cause vibrations (called mirror slap) that may produce blur in a photograph - especially at a shutter speed ranging from 1/2s to 1/60s. The problem is often most evident in macro photography, or while using longer focal lengths.
Mirror lock-up is a camera mechanism that involves flipping the mirror up before the shutter opens, allowing the vibrations to settle before an exposure is made. Mirror lock-up features in many SLR and DSLR cameras. The function can be switched on in Live View in most digital cameras, and activated with a switch on film configurations. To avoid running down the batteries in Live View, some DSLR cameras also have a separate MLU function which allows a user to press the shutter once to flip the mirror up and then a second time to make the exposure. Combined with a remote or cable release, MLU can significantly reduce the visual manifestations of vibration.
An issue found in DSLR and SLR cameras, mirror slap occurs because of the mechanical configuration inside the Single Lens Reflex camera system. At rest, a mirror inside the camera helps bounce light from the lens into the viewfinder so it can be viewed. When a photograph is made, the mirror flips up, allowing light to make contact with the camera's image sensor. However, when the internal mirror flips up for an exposure, it creates a small vibration. In some cases, this vibration can blur an image during an exposure, especially at shutter speeds between approximately 1/100s and 1/2s. The effect of mirror slap can be counteracted with mirror lock-up mechanisms.
ND Filter (Neutral-density Filter)
An ND or neutral-density filter is a filter that reduces or modifies the intensity of all light that passes through it. ND filters attach to the front of a camera lens. In scenarios where long exposures are desired in bright conditions, an ND filter helps cut down light to avoid overexposure.
In digital photography, the term noise refers to the visual graininess of an image. There are two types of noise, shot noise and digital noise. Shot noise is caused by inconsistencies in photon behaviour, whereas digital noise or electronic noise is caused by the internal electronics of a camera. At high levels, noise can decrease the quality of a digital photograph.
Overexposure is the exposure of a film or sensor to light for too long. A long exposure at midday in bright conditions without an ND filter will likely cause overexposure, which manifests as undesirably bright images with considerable loss of detail.
In photography, panning means activating a longer exposure and swivelling a camera from a fixed position, keeping the lens square with a moving subject. Panning enables a photographer to capture moving subjects while conveying an exaggerated sense of movement.
A polarizing filter is a filter attached to the front of a camera lens to add contrast, darken the appearance of skies, reduce reflections and suppress glare. However, a polarizing filter also reduces the amount of light reaching the camera sensor, so it is less ideal for low-light conditions.
Remote Trigger/ Shutter Release
A remote shutter release or trigger is a remote that can be connected to a camera either wirelessly or via a cable. The main function of a remote trigger is to activate an exposure without physically depressing the camera's shutter release button. Using a remote trigger cuts down on unwanted camera shake and aids with photographing self-portraits, light painting or photographing wildlife.
In photography, a shutter is a device inside a camera that allows light to make contact with a sensor or film for a determined amount of time.
There are two types of shutters - mechanical and electronic. In mechanical shutters, the two most common configurations are the focal plane shutter and the leaf shutter. The focal-plane shutter is positioned within the camera body, just in front of the sensor. When the shutter button is depressed to activate a slower shutter speed, the forward curtain in the focal plane shutter opens and the camera sensor is exposed to light in its entirety. When the set shutter speed time expires, a second curtain closes the sensor off, completing the exposure. Faster shutter speeds are achieved with a travelling slit moving across the sensor, permitting light to be converted into a photographic image in a quick sweep.
Unlike focal plane shutters, leaf shutter configurations are usually located within a lens, rather than inside the body of the camera. Made up of a number of thin, overlapping blades arranged in a circular pattern, the leaf shutter opens up in an oscillating fashion to guide light through to the sensor. Although leaf shutters are more compact and durable, they are typically not capable of reaching shutter speeds as high as modern focal plane shutters.
Electronic shutter systems work a little differently again. In basic terms, when the exposure button is depressed, the sensor switches on to commence the exposure line-by-line and switches off again to complete the process. Nevertheless, the duration the sensor is active is still called the shutter speed.
Electronic shutters are silent, have higher shutter speeds and can minimise the camera shake seen with mechanical shutters. However, flash sync speeds are much lower, and they don't perform well under flickering lights.
Shutter shock can be a problem in all cameras, although it is most common in mirrorless camera configurations. Mirrorless cameras are constructed with an exposed sensor, so the shutter curtains must move into place before an exposure begins. This process can cause vibrations that manifest in digital images as unwanted blur.
Blur from shutter shock usually occurs within a window ranging from 1/100s to 1/2s approx. In addition, the longer the focal length, the more likely the effect occurs. Some cameras have an Electronic First Curtain Shutter (EFCS) system to combat shutter shock, while others provide the option of a short delay between when the shutter button is depressed and when the exposure is taken.
When the shutter button is pressed to make an exposure, a shutter inside the camera opens, permitting light through to the camera sensor for a set amount of time known as shutter speed. This means that the shutter is responsible for two specific things: controlling the brightness and darkness of a photograph and creating dramatic effects by freezing action or rendering blurred motion. A shorter shutter speed freezes movement, while a longer shutter speed captures blurred motion.
Single Lens Reflex (SLR)
A single-lens reflex (SLR) camera is a camera with an internal mirror and prism system that allows a user to see a composition through the viewfinder before the image is made. When the shutter button is depressed on an SLR camera, the mirror component flips up, permitting light to pass through to the film to record an exposure. This system has translated to the DSLR (Digital Single Lens Reflex).
When a stationary camera captures the transit of stars with a long exposure, streaks across the night skyscape begin to manifest as glowing trails.
A tripod is a device used to support and stabilize a camera. Using a tripod in conjunction with a remote trigger will help to minimise unwanted camera shake. Alternatives to tripods include the monopod, which has a single leg instead of the three on a tripod.
Tv stands for Time-value, but is better known as the Shutter-priority mode - a setting that allows photographers to make a manual shutter speed selection whilst the camera automatically chooses an appropriate aperture value for an exposure.
Underexposure occurs when the camera sensor or film is not exposed to enough light to create the desired image. For example, fast shutter speed photography at night without a flash will likely cause underexposure, which manifests as undesirably dark or murky images.
In photography, a vignette is a shadowy border that occurs at the periphery of photos. Vignetting can be caused accidentally by camera settings or equipment, or they can be introduced intentionally in-camera or in post-production. Some types of vignetting occur due to the optical design of lenses, others can occur when using accessories like filters and hoods.
Optical vignetting, which occurs naturally in most lenses, is most prominent at large apertures. Fast prime lenses exhibit a lot of vignetting at the widest aperture but the aberration lessens dramatically as the aperture is stopped down.
The Waterhouse diaphragm or Waterhouse stop is an interchangeable diaphragm system invented by the 19th-century photographer John Waterhouse of Halifax in 1858. The Waterhouse stop consisted of a number of diaphragms, each with a different sized hole for limiting the amount of light entering a camera. The holes correspond to what is now known as an f-number or f-stop.
Today, Waterhouse stops are generally obsolete, with most modern photographic lenses made with an iris diaphragm. However, the Lensbaby line continues to use interchangeable apertures, a range of cameras designed to produce effects normally associated with view cameras. Some of these drop-in aperture disks are designed in unique shapes and patterns to render shapes in instances of bokeh.
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