Re: Digital cameras & depth of field (my experience)

video guy - www.locoworks.com wrote:

Dan, come back to earth.  We are talking photography here, not rocket
science. I give you this quote from
http://www.pinhole.org/about/index.cfm (which you would do well to
visit).

"Pinhole images are formed by a beam of light, the diameter of which
governs its sharpness. The diameter of the beam is determined by the
diameter of the pinhole...so, a really big pinhole will make a less
sharp image and a very small pinhole will make a very sharp; but not as
sharp as a lens, image."

The pictures on exhibit in the gallery there are quite amazing.
Dimensions, relative f-stops, and other detail are available there too.
 And by the way, I made a pretty good living with that antiquated
ray-optics for thirty years.  I shall not desert it now!

No need to, and I don't want to start a war, BUT, never extrapolate something beyond it's realm of validity.

I don't care where your earlier statement came from, it's still WRONG! It's slightly wrong for even large holes, and TERRIBLY WRONG for small diameter (pin) holes!

And, yes, ray optics works fine for many things, it's a useful tool. However, like ALL tools, there's things it's good for, and things it's NOT. Ray optics will correctly show you approximately HOW a pinhole forms an image (size and location), but will not at all account for the soft focus that results from a very small pinhole. "Tunneling" (your term) has little or nothing to do with THAT, it's almost pure diffraction!

Try using ray optics to explain Holography! That too is an effect only well explained by wave optics. Holography is closely akin to many diffration effects, being the result of constructive and destructive wave interference.

Dan Mitchell
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Relevant Pages

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