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Old July 2nd, 2011, 11:44 AM
Bart_van_der_Wolf Bart_van_der_Wolf is offline
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Join Date: Jun 2006
Location: Netherlands
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Originally Posted by Nick Masson View Post
Thanks for the replies. It seems, then, that there is little use in stopping down to f/22 or so unless your composition includes a subject quite close to the lens (5 to 10ft).
Hi Nick,

The unsharpness that's added as a veil over the entire image is directly related to the F-number. The F-number itself is a ratio of focal length and aperture diameter (therefore also written as f/#), and is the most important factor in determining diffraction blur. Small apertures, therefore large F-numbers, produce a lot of diffraction blur.

Distance is only important for the Depth of Field (DOF) blur at certain distances away from the plane of focus.

Asher and Doug, would you suggest any literature about optics resolution, and particularly hyperfocal technique etc... It is something that has always interested me.
One of the most accurate on-line descriptions can be found at: and

And of course Doug has written a paper about the subject, but his webpage seems to be not responding right now.

If you do what you did, you'll get what you got.
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