Jargon of The Month
''A shot's depth of field is the zone of sharpness in front of and behind the subject on which the lens is focused. Depth of field can be altered by changing the aperture of the lens.''
Don't know your aperture from your elbow? Get up to speed fast with our quick guide to photography jargon
Aperture-priority mode
Using aperture-priority mode (A) on a camera gives you the freedom to alter the lens's aperture. The camera then automatically selects the correct shutter speed to ensure you get a perfectly balanced exposure. Aperture-priority is particularly useful if you want to control the depth of field in your image.
Aperture
The aperture of a lens is a circular, adjustable hole called the diaphragm that allows light into the camera. Apertures are measured in f-stops. The smaller the f-stop (eg f/2), the more light is let in. The larger the f-stop (eg f/32), the less light is allowed in. By changing the aperture you can change your image's depth of field.
Auto mode
This is your fail-safe shooting mode, where the camera decides the shutter speed and lens aperture, so all you have to do is frame the shot and press the shutter button.
Autofocus
Your camera’s autofocus system measures the distance of the subject from the camera and automatically refocuses the lens for a sharp picture.
Backlight
A subject that's backlit (with the light behind it) can end up being underexposed - too dark and lacking in detail. Correct this with ‘fill-flash' or backlight mode, where the camera fires a burst of flash to brighten up your subject. You can deliberately use backlighting for punchy silhouettes.
Bracketing
If you're having problems getting the exposure right, use your camera's bracketing feature to get a range of exposures for the same subject. This will give you a version of the shot that's just under the exposure suggested by the meter, one that's at the metered exposure, and one that's just over the meter's recommendation. You can then select the one that's the most accurate.
Camera shake
This is blurring of an image caused by the camera moving while you're taking the shot. It's common with long exposures. You can avoid it by stabilising the camera on a tripod, or using its vibration reduction mode - some lenses have this built-in, too.
Compact cameras
These feature a built-in lens, usually a zoom, and some take lens converters to extend their focal length range. Their main advantages are that they are usually quite small, lightweight and portable, with lots of point-and-shoot technology for making image capture quick and easy. Many also have lots of advanced features to give you more creative control over your imaging.
Compression
A method for reducing file sizes for storage or transmission. Compression algorithms can be divided into "lossless" algorithms, in which no information is lost when files are restored to their original size for display or editing, and "lossy" algorithms, such as JPEG, in which some information is lost when the file is restored.
Contrast
This is the range of tones in an image between the highlights and the shadows.
D-SLR
Digital SLRs (single lens reflex) enable you to use a huge range of interchangeable lenses, just like film-based SLRs. You also have more scope to use lots of accessories, such as additional flashguns and lens filters. They are generally larger and heavier than compact cameras, and tend to give you a greater degree of creative control, but they can usually be used for point-and-shoot photography, too.
Depth of field
A shot’s depth of field is the zone of sharpness in front of and behind the subject on which the lens is focused. Depth of field can be altered by changing the aperture of the lens. A large aperture (small f-stop number) gives a very shallow depth of field with a limited area of focus, usually a sharp foreground and blurred background that can be great portraits. If you’re shooting a landscape and want to keep everything in sharp focus throughout the image, you’ll need deep depth of field (small aperture, large f-stop number).
Digital Zoom
Digital zoom increases the magnification of part of the image while it’s viewed on the camera’s LCD screen. It usually reduces the quality of the image, so if quality is important use the optical zoom lens instead.
Effective resolution
This refers to the number of pixels on the sensor actually used to capture the image. This is sometimes less than the crude sensor size, because some pixels on the sensor are used for functions other than image capture.
Electronic viewfinder
What you can see through an electronic viewfinder is the image captured by the lens projected electronically onto a small display. The electronic viewfinder can also display the settings for the shot you’re looking at.
Exposure compensation
Using an automatic exposure mode may sometimes not give you the result you want. To help, many cameras have an exposure compensation setting, which enables you to override the automatic setting and increase or decrease the exposure in very small increments. You’d generally be adding compensation if the subject was too dark (underexposed), and reducing it if your subject looked too bright (overexposed).
Exposure
This is the amount of light falling onto a digital camera’s sensor (or the film of a film camera). Exposure depends on the aperture of the lens and the shutter speed, plus the camera’s ISO setting (or the ISO of the film you’re using in a film camera). Your camera automatically measures the amount of light falling on the subject using its built-in light meter to give you a shot that’s correctly exposed – not too dark, not too light.
Fast lens
This is a lens with a larger maximum aperture (smaller minimum f-number), which enables it to let more light through to the sensor so you can use a faster shutter speed.
File size
The more information and therefore pixels there are in a file, the greater its size.
Fisheye lens
A lens with an extremely wide angle of view, usually giving 180° coverage – a bit like looking through a curved goldfish bowl. It creates very curved, sometimes circular, images, with all straight lines on the edge of the image area bowing outwards.
Fixed focal length lens
This type of lens has only one focal length. It’s also known as a prime lens.
Flash
Flash is used for brightening up images when the available light is poor, cutting out shadows, reducing red-eye and also for special effects. Cameras usually have a built-in flash that automatically fires when the light is low. D-SLRs and some compact cameras also have the option of using additional, more powerful external flashguns. These can either be fixed to the camera or used remotely using cables or wireless control.
Flash
The aperture settings on a lens are measured in f-stops or f-numbers. The f-number is basically the relationship between the focal length of the lens and its aperture. The larger the f-number, the less light is let into the lens and the greater the depth of field. Using the same f-number on any focal length of lens should give the same exposure, as long as the same shutter speed and light levels are used. So, if you increased the aperture by one f-stop, you’d need to halve the shutter speed to get the same exposure.
Focal length
The focal length of a lens determines the angle of view of your shot. The longer it is, the more it can magnify what you are shooting. So a short focal length will give you a wide, sweeping shot with little magnification, while a longer focal length can be used to bring faraway subjects closer by hugely scaling them up.
Frames per second
This refers to the number of continuous shots a camera can take. It’s very useful for fast-action situations, such as sports, giving you a better chance to catch the shot you’re after.
Image processor, image processing system, image-processing engine
The image processor in a digital camera uses a combination of hardware processors and software algorithms to decide the correct colour and brightness values for each pixel in an image recorded by the sensor. The more powerful and accurate the image processor, the better, more realistic and natural-looking are the colour, sharpness and contrast in your image.
Infinity
This is the furthest possible distance on which a lens can focus.
Iso
When you choose an ISO level, you’re altering the camera’s sensitivity to light. Low ISO settings, such as ISO 100 or 200, are fine for bright conditions like a sunny afternoon. The darker it gets, the more sensitive to the available light you want the camera to be, so go for a higher ISO setting, from ISO 800 upwards. It’s exactly the same with film – use a low ISO rated film for daylight, and a higher ISO rated film for duller conditions. But remember that by increasing the ISO sensitivity on a digital camera, you might noticeably increase the amount of noise in your image.
JPEG
JPEG is a file format used on most digital cameras. Three image quality settings available using the JPEG compression file format, Basic, Normal and Fine found on most Nikon digital cameras. JPEG compression is "lossy," meaning that information is lost when images are compressed. Compression selectively reduces the quality of the image; the more the picture is compressed, the more noticeable this loss of quality is likely to be apparent.
LCD screen
Usually on the back of the camera, the LCD screen can be used to compose your images in real-time and then play back what you’ve taken. It also usually shows you the camera’s menu of features and functions, such as scene modes and ISO settings.
Lens
The lens focuses light onto your digital camera’s sensor (or the film in a film camera) to form the image of the subject you want to capture. Its focal length indicates your photograph’s angle of view. The larger the focal length, the more magnifying the lens; the shorter the focal length, the more wideangle the lens. Lenses are usually made up of a series of lens elements which correct for distortion to produce a sharp, realistic image. Compact cameras have a built-in lens, while D-SLRs have removable lenses..
Macro
If your camera has a macro mode (usually shown with a flower symbol), or you use a macro lens, you can focus on very near objects, usually closer than 30cm to the camera. This enables you to record very fine details in, for example, plants and insects. Macro ensures maximum depth of field so as much of the detail as possible is captured in sharp focus.
Manual exosure mode
Instead of the camera automatically working out the exposure and/or aperture settings, in this mode you do the work. This means you’ve got to be confident about setting both the lens aperture and the shutter speed, based on information from the camera’s meter about the quality of the light you’re shooting in. The beauty of manual mode is that it gives you total creative control over your pictures.
Megapixel
One megapixel equals one million pixels.
Meter
The meter (also known as the light-meter) measures the amount of light in a scene, and this information is then used by the camera to set the optimum exposure.
Noise
Random coloured pixels which appear in dark areas of the image when light levels are below the sensor’s sensitivity range are called noise.
Normal lens
This type of lens is also called a standard lens. It is usually 35mm or 50mm and because it has an angle of view and magnification closest to the naked eye, it provides a natural image perspective. This makes it ideal for a variety of subjects, including candids, landscapes and full-length portraits. Normal lenses are usually quite fast, too, so you’re less likely to need flash when using them in low light.
Optical viewfinder
An optical viewfinder is what the photographer looks through to compose shots. Its main advantage over an electronic viewfinder is that they require no power..
Overexposure
If your shot is too light, with bleached-out colours and no depth, it’s overexposed – which means too much light has hit the camera’s sensor.
Panning
With this technique, you follow a moving subject horizontally with the shutter button depressed, so it’s captured sharply against a blurred background to create the impression of speed.
Pixels
A digital image is built up from a set of small coloured rectangular or square dots called pixels (short for ‘picture elements’). The more pixels a picture has, the greater its detail. So the more pixels a digital camera has on its sensor, generally the higher the resolution of the images it captures
Point
Directing the camera in a quick and spontaneous way, to generate a random and abstract shot.
Program mode (P)
In Program, the camera decides the shutter speed and lens aperture. Where it differs from Auto is that you can still alter the other functions, such as exposure compensation and flash settings.
RAW
Digital SLRs and top-spec compacts usually offer the option of recording your images in a RAW file format. RAW retains all the information originally captured, creating files that are bigger than JPEGs but usually smaller than TIFFs. Professional photographers usually shoot in RAW, as these files can be very easily manipulated using a software package such as Nikon Capture NX or Photoshop.
Red eye
Red-eye is the red pupil effect you sometimes get when using flash. It’s caused by light from the flash being reflected back through the lens from the blood vessels in your subject’s eyes. Many cameras have built-in techniques to counteract red-eye. These include firing a series of mini pre-flashes to make the pupil contract prior to taking the shot (the narrower the pupil, the less light can pass through to the retina). Some cameras, such as Nikon’s COOLPIX range, use an automatic, in-camera red-eye detection and correction system after the image is taken.
Resolution
Resolution is the total number of pixels in an image – basically, it’s the amount of information it contains. It’s calculated by multiplying the number of vertical pixels by the number of horizontal pixels. Resolution is usually measured in megapixels. The larger the number of pixels, the greater the resolution and, generally, the better the quality of the image. It’s worth noting that image quality also depends on the size of the camera’s sensor and the quality of the lens in use.
Scene modes
These are automatic settings that use pre-programmed, optimum combinations of shutter speed and exposure for specific subjects such as close-ups, portraits and action shots. For example, landscape mode (usually indicated by a mountain icon) selects a smallish aperture to create a large depth of field, keeping as much of the scene in focus as possible. Some scene modes also trigger the flash to fire so you get the right amount of detail in your shot.
Sensor
The sensor is the part of the camera that captures the image. Basically, it converts light falling onto it into an electrical signal that is then translated by the camera’s image processor into a digital image. There are two main types of sensor: CCD (charge-coupled device) and CMOS (complementary metal oxide semiconductor). Both types consist of a grid of light-sensitive photodiodes called pixels, and the total number of pixels is the sensor’s resolution.
Shutter priority mode (S)
In this type of exposure mode, you choose the shutter speed you want to use, and the camera automatically determines what the lens aperture should be to ensure a correctly exposed shot.
Shutter speed
The amount of time for which the sensor (or film on a film camera) is exposed during an exposure. Slow shutter speeds enable you to shoot in low light and can be used for creative blurred effects. Fast shutter speeds freeze action and prevent camera shake from blurring your shots.
Stopping down
This means reducing the lens’s aperture by choosing a higher f-number. This cuts down on the amount of light entering the lens and increase the depth of field. You’ll often see it referred to as a number of stops faster or slower.
Storage media
These are memory cards used in your camera to store hundreds of images (depending on the file format of the images you shoot). Different camera makes and types use different types of memory cards. The most common are CompactFlash, which tend to have the largest capacity, and SD cards, which are physically smaller and so are often used in compact cameras and small D-SLRs.
Telephoto lens
This type of lens has a long focal length so distant subjects appear larger, without you having to get too physically close. Telephotos are ideal for sports, portraits and wildlife shots.
Tiff
TIFFs are image files which use a ‘lossless’ compression method, so they retain all their original pixels. However, this makes them much larger than JPEGs, so you can’t save as many onto your camera’s memory card. They can also take longer to save to the card, which means a bigger gap between picture-taking opportunities.
Underexposure
If your shot is too dark, with not enough detail, it’s underexposed. This means not enough light has reached the camera’s sensor to record the image properly.
Vibration reduction
VR is a type of technology in Nikon cameras and lenses that minimises the effect of camera shake when photo taking.
White balance
Daylight and artificial light are completely different, with different colour temperatures. You don’t notice this because the human brain is good at compensating for these differences. However, cameras can only capture the actual colour, which means colour casts can result and spoil your shots. White balance corrects colours in-camera so they appear neutral, no matter what colour the lighting actually is. Most digital cameras have an automatic white balance control.
Wideangle lens
A wideangle lens has a short focal length and provides a small image magnification but a wide field of view with a deep depth of field, enabling more of a scene to be photographed in sharp focus. It’s ideal for landscapes and any situation where you want to get a sweeping viewpoint.
Zoom lens
This type of lens has a variable focal length. This enables you to change the field of view and the image magnification by zooming in or out, without you having to change position. Zooms are very versatile and can be used for most shooting situations.
