On Mon, 23 Dec 2002 18:13:43 +0900, "David J. Littleboy"
>"Tony Spadaro"
>news:_zzN9.57352$Rt1.2448959@twister.southeast.rr.com...
>> Diffraction causes small apertures to lose sharpness, but in general not
>> enough to worry about. Most lenses will not close down to the point where
>> the image is noticably damaged by diffraction.
>If you are scanning Provia 100F, Velvia, Tech Pan at 4000 dpi, you should be
>able to notice the difference between f/8 and f/16 or f/22...
>David J. Littleboy
>Tokyo, Japan
Even in low-resolution systems, like video cameras,
the effects of diffraction can easily be seen. At
this URL are samples of stills shot with a video
camera (Sony VX2000), where stopping down below
about f4 gradually softens image-center detail.
The surprise for me, after putting up this web page
(using the still-photo function of the camera), was
finding out that the motion-video images (which are
even lower in resolution) also clearly showed the
effects of diffraction...
See: www.David-Ruether-Photography.com/diffraction.htm.
David Ruether
On Mon, 23 Dec 2002 17:48:17 GMT, "Tony Spadaro"
> I would assume that the video lenses are more to blame.
?????????
Unlikely if you see a decline in resolution with
stopping down - that is generally a diffraction
effect (and in the samples, you can see the
diffraction effect increasing with smaller stops
in the increasing sizes of the "star" sun
reflections on the car [the star is a combination
of diffraction around straight sides of the
diaphragm leaves, and of a "HAD" CCD effect [the
vertical rays are caused by this...]).