Tuesday, July 15, 2008

10 terms you should know

One of the podcasts I've started listening to "This Week in Photography" (http://twipphoto.com/) had a Q&A section of one of their podcast. One of the questions was: What ten photography terms would you say are "Must knows". They had a few of the ones I would highlight but I thought I would do my own list. Alright its not 10 but here goes:

The aperture is the hole that the light passes through. Usually we talk about the size of the aperture however. A larger aperture lets more light in however it decreases depth of field. Conversely, a smaller aperture lets in less light but increases depth of field. Aperture size is usually described in f-numbers. The larger the number the smaller the aperture. I like to think of the f as 1. So in the case of f/22 I would think of it as 1/22. Obviously 1/22nd is smaller than 1/5 (i.e f/5)

Shutter speed
Shutter speed describes how long the shutter is open for. The longer the shutter is open the more light is let in.

Camera shake
Camera shake is a common problem in photography when telephoto lenses or long shutter speeds are used with a non-stabilized camera. The resulting images will appear blurry and smeared. There are two primary ways of counteracting camera shake. A tripod will stabilize the camera. Additionally a higher shutter speed will help. As a rule thumb the inverse of the focal length is a good speed as a minimum. (e.g. a 50 mm focal length would require a shutter speed of at least 1/50 second).

ISO describes the sensitivity of the film or sensor. A higher number indicates a higher sensitivity. With higher sensitive more grain (in film) or noise (with digital) occurs.

Hyperfocal Distance
Distance of the nearest object in a scene that is acceptably sharp when the lens is focused on infinity.

White balance
White balance (WB) is the process of removing unrealistic color casts, so that objects which appear white in person are rendered white in your photo. Proper camera white balance has to take into account the "color temperature" of a light source, which refers to the relative warmth or coolness of white light. Our eyes are very good at judging what is white under different light sources, however digital cameras often have great difficulty with auto white balance (AWB). An incorrect WB can create unsightly blue, orange, or even green color casts, which are unrealistic and particularly damaging to portraits. (from http://www.cambridgeincolour.com/tutorials/white-balance.htm)

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