Samsung BN59-01012A 数据表

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Concepts in Photography
Correlation between focal length, angle, 
and perspective
Focal length, which is measured in millimeters, is the distance between 
the middle of the lens to its focal point. It affects the angle and perspective 
of captured images. A short focal length translates into a wide angle, 
which allows you to capture a wide shot. A long focal length translates 
into a narrow angle, which allows you to capture telephoto shots.
9 mm angle
27 mm angle
Depth of field
Portraits or still-life photos mostly acclaimed by people are the ones on 
which the background is out of focus so the subject looks pronounced. 
Depending on the focused areas, a photo can be blurred or sharpened. 
This is called 'a low DOF' or 'a high DOF'.
The depth of field is the focused area around the subject. Therefore, a 
small DOF signifies that the focused area is narrow and a large DOF means 
the focused area is wide.
A photo with a small DOF, which stresses the subject and makes the rest 
of it blurred, can be obtained by capturing a photo close to the subject or 
selecting a low aperture value. Conversely, a photo with a large DOF which 
shows all the elements on the photo sharply focused can be achieved by 
capturing a photo far from the subject or selecting a high aperture value. 
Small Depth of Field
Large Depth of Field