ISO,+F-Stop,+Shutter+Speed

media type="youtube" key="F8T94sdiNjc" width="560" height="315" Definition of:** f-stop ** from[| PC Magazine Encyclopedia]  (**F **ocal-**STOP **) The measurement of the aperture setting in a camera lens. The f-stop setting determines how much light is allowed to enter the lens and pass through to the film (analog) or CCD or CMOS sensor (digital). It also determines how much in front of and behind the subject is in focus (see [|depth of field] ).

The f-stop is the focal length of the lens divided by the diameter of its opening. Each consecutive f-stop halves the opening of the previous. For example, an 80mm lens with its f-stop set to f8 means that the optics inside the lens create a diameter equivalent to 10mm. Changing the f-stop to f16 creates a diameter of 5mm. See [|focal length].
 * Length Divided by Opening **

[|Easy F stop tutorial]  Definition of:** ISO speed ** From [|PC Magazine Encyclopedia] The international standard measurement of a camera's sensitivity to light, often simply called the "**eye **-so." For analog film cameras, the ISO is the "film speed," which is based on the chemical composition of the film. Changing ISO means loading a film with a different speed. With digital cameras, it can be changed by selecting a speed from the ISO menu, reconfiguring an electronic circuit that emulates film speed.

If the camera's shutter speed and aperture cannot be altered for certain scenes, changing the ISO is a third variable that can accomplish the desired exposure. In a digital camera, ISO can be set manually or automatically.

In a digital camera, higher ISO speeds are accomplished by amplifying the electronic output of the sensor, and some cameras have speeds up to ISO 10,000. However, the more signals are boosted, the more noise is generated, which is equivalent to the grainier image that appears in analog film at ISO 1600 and higher.
 * High ISO Noise **

Unless a grainy effect is desired, shooting at ISO 64 and ISO 100 has always been the recommended norm. However, each generation of digital cameras is able to use a higher ISO with less noise, and higher and higher speeds are routinely used. Some digitals have ISO speeds up to 6400 and more, and most cameras also have high ISO noise reduction (NR) circuits that can be selected to help smooth the resulting images. Definition of:** shutter speed ** In a still camera, the length of time that the shutter is open, exposing the film (analog) or CCD or CMOS sensor (digital) to light for a single image. In a camcorder, the shutter speed is the frame speed; for example, 24, 30 or 60 frames per second (fps). See [|exposure] and [|shutter lag].



=How ISO, Shutter Speed, and F-Stop Work Together=