Depth of field

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24.06.2011 12:14:00
depth of field.

DOF (depth of field, or DOF) in the photographic business - the distance between the proximal and distal boundaries of space, measured along the optical axis, while within which objects are in focus (the image will sharply enough).

depth of field depends on the aperture value, subject distance, and the size of the photosensitive material (film or matrix).

If you shoot a subject from a distance of 30-40cm using NX lens 30 mm, then setting a maximum aperture of f / 2 will get a minimum depth of field.



That is the distance in front of and behind the object on which the remaining items will be sharp, very small.

If you cover up the aperture to a value such as f / 8, then increase the depth of field and the distance at which objects will increase dramatically.



In order to obtain the greatest possible depth of field, use a small aperture (f22). But because it passes through it in less light, the exposure time (shutter speed) will have to increase.

So if exposure with aperture f / 8 and shutter speed 1/180 - enough to make a sharp image.



In the same light conditions at f / 22, the shutter speed should already be 1/15 (but will need to use a tripod).



control the depth of field you can manually M, where necessary by setting the aperture, you yourself will choose the corresponding shutter speed.

And also you can use the automatic camera and take pictures in the "Aperture Priority" - And, using which you yourself set your desired aperture and the camera exposure meter, will choose for you the necessary data in terms of light exposure.

As we approach the object, try to fade out the lens so that the depth of field is minimized. This will help the viewer to focus on the main subject, as in this case.



The most common reason for using a wide aperture - the desire to limit the depth of field for portraits. This allows you to highlight the main subject and the background will become softer and more blurred.



relationship aperture and depth of field is visible in the pictures. The ability to apply this law is very important for such photos that will attract attention.

Consider an example.

f4 1/100

for this image was used NX 50-200 mm telephoto lens and aperture f4. A sufficiently large part of the frame is out of focus.

If you close the aperture to a value of f / 8

f8 1/50

clearly visible steel and other parts of the picture. A diaphragm f / 22, the focus will be not only the entire foreground, and background.

Landscapes mostly photographed at short focal lengths, so the frame can obtain a wide space. It will also use a small aperture opening (aperture value-f / 22), that lead to a large depth of field. F / 11 and f / 16 will not be uncommon, if you analyze the parameters of landscape photography.



Under normal focal length (30mm) and a large aperture of f2 - depth of field is so small that even closely spaced blades of grass spread out, and items located at a distance, are indistinguishable.

f2 1/4000

Under normal focal length (30mm) and a small aperture - f / 8 - depth of field increases, so distant objects like approach.

f8, 1/250

So, the main reason for the migration of the diaphragm - to change the depth of field.

To increase the depth of field (most of the frame becomes sharp) increase the value of f, t. E. Put a smaller aperture.



To reduce the depth of field (lower part of the frame becomes sharp), reduce the value of f, t. E. Put a larger aperture.

f2 1/4000

Samsung NX lenses have a wide range of aperture, allowing you to create a variety of unforgettable images.
 

24.06.2011 13:28:00
Since the perception of depth of field also depends on the size of the printout, or images on the screen, it would be nice to make a larger illustrations, and then, for example, the difference between f4 and f8 is not too conspicuous.
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Depth of field

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