Sigma C72900 User Manual

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EV 
Exposure Value (EV) is a numerical value that expresses the amount of light for a 
given exposure, and depends on brightness of the photographic subject and 
sensitivity of the film. If a photographic subject is bright, then this numerical value will 
be large, and if the subject is dark then this numerical value will be small. If two-times 
of light reaches the film surface then the difference in exposure value will be +1, and 
if the amount of light is reduced by half, the exposure value changes by -1. 
Histogram 
The histogram function is a graphic representation of how bright and dark pixels are 
distributed in an image. The histogram function enables a precise check on the 
exposure of the photo.   
ISO Sensitivity 
ISO(International Organization for Standardization); refers to the number assigned 
to each silver halide film, which indicates film speed or the film's relative sensitivity 
to light, the higher the number, the greater photosensitivity and vice versa. Digital 
cameras also use standard ISO sensitivity ratings like silver halide films.   
JPEG 
Joint Photographic Experts Group has established a standard method for 
compressing and decompressing the digitized images. If the rate of compression is 
high the file size will be small but picture quality will be decreased. 
NTSC  
National Television Standards Committee (NTSC) video format is primarily used in the 
United States, Japan, Canada etc. The NTSC is a standard for television and videos, 
which defines a composite video signal with a refresh rate of 60 half-frames (interlaced) 
per second. Each frame contains 525 lines and can contain 16 million different colors.   
PAL 
Phase Alternating Line (PAL) video format, primarily used in Europe, excluding 
France, as well as Australia and parts of the Far East. PAL delivers 625 lines at 50 
half-frames per second.   
RAW 
The RAW image format is the data as it comes directly from the image sensor of the 
camera. No in-camera processing is performed before transferring the image to 
computer. 
Shutter Speed 
The camera’s shutter opens for a length of time to control the amount of light that 
reaches the imaging element. The length of time that shutter blinds are open 
allowing light to strike the image sensor is called a shutter speed. 
White Balance 
The human eye and brain adapt to changes in lighting conditions, not only to intensity, 
but also to the color characteristic of the light source, so that colors of the objects 
look normal or accurate. For example, a white object will appear white whether it is 
viewed under sunlight, tungsten or fluorescent illumination. However, color film or 
digital camera must be adjusted, so that colors will be represented accurately, under 
different types of illumination. This adjustment is called white balance. The function to 
adjust a white balance automatically is called automatic white balance.