I thought about when I was beginning to learn photography and I was baffled by all the terminology and what it all meant, so I thought I’d put it in basic layman’s language and put it on my site for all, to try and help anyone who is just starting out.
Aperture – Like the iris in your eye. Controls how much light is let in through the lens. The size is measured in f stops; the lower the number, the wider the aperture. E.g. a number of f4 is wide open, f16 is a small opening. If you increase the f- number by 1 stop (e.g. f4 to f5.6) it decreases the amount of light by half. Also controls how much of the image is in focus. Higher numbers mean more is in focus from front to back of the image.
Shutter speed – length of time the shutter is open. Measured in seconds from 1/4000th of a second to 30 seconds. If the shutter speed is doubled the amount of light is halved. Also known as exposure time. Bulb setting is for locking the shutter open for extremely long exposures.
Exposure – The taking of a picture. Correct exposure is a combination of aperture and shutter speed letting the right amount of light into the camera. Under exposure is not enough light, over exposure is too much light. Therefore it’s desirable to have the combination of aperture and shutter speed right for the amount of light available.
Metering – calculating which aperture / shutter speed settings to use. Cameras have a built in meter to work this out for you or you can get an off camera light meter to take readings.
F-stops – the aperture measurement. The numbers on the lens barrel indicate the f-stop. Also known as stops.
Bracketing – taking a number of images either side of correct exposure. I.e. you take an image at correct exposure and then under expose and over expose by a number of stops, normally 1 or 2. Any of these exposures could be correct depending on the effect you want in the final image.
ISO – Used to be the industry standard for film speed. The ISO number indicated how much light the film would record. ISO 100 would need a lot of light whereas ISO 800 needs less light but the higher the ISO the more ‘grainy’ the picture. In the digital world the ISO determines how sensitive the sensor is. The higher the ISO the more light is captured but also how grainy or ‘noisy’ the image is.
Depth of field – (DOF) The proportion or distance of objects that are in focus. E.g. a tree in the foreground is in focus but the landscape is out of focus, or everything is in focus. This is the photographer’s main artistic tool. You can show a subject in its environment or just give a hint of its environment by having the background blurred. The aperture controls this. The wider the aperture the more blurred the background.
Neutral density (ND) filters – darkened resin or glass that fit in front of the lens. They reduce the amount of light entering the lens by a number of stops. Used to get slower shutter speeds for effects like silky water or streaking clouds.
Graduated ND filters – used to prevent over exposure of part of the image. E.g. the sky is generally brighter than the foreground so using a graduated filter prevents the sky being too light. Graduated filters come in hard and soft edged and in various f-stop grades.
Polariser filter – cuts out unwanted reflections, makes the sky more blue and makes snow look whiter.