Re: Matching lenses - distortion/Digression

[erker@xxxxxxxxxxxxxx (Greg Erker)]

>The whole reason for the toy camera and pinhole cultists to pursue their
>thing is to achieve varying degrees of low resolution/distortion.
>Photographers such as Wee Gee (late in his career) were rather famous
>for introducing rather wild distortions in his prints using various
>lenses and prisms. And of course perspective distortion (really
>perspective mismatch) from wide angle lenses is a current flavour of the
>year, especially high angle stuff shooting down for some reason; go
>figure.

  There was a discussion of Bokeh on
rec.photo.equipment.35mm which as I understand
it relates to distortions in the out of focus
image. No usually an issue in 3d but some photos
can benefit from selective focus.

  One poster mentioned a Nikon portrait lens
that has adjustable bokeh. See:
http://www.klt.co.jp/Nikon/PPD/Lineup/Lenses/Guide/opt_tech2.html

---
"Defocus-image Control AF DC-Nikkor lens
One of Nikon's unique contributions to
portrait photography is DC (Defocus-image Control)
technology. This unique Nikon innovation enables
users of AF DC-Nikkor lenses to control background
and foreground blur precisely, resulting in striking
portraits. These lenses are the only ones of their
kind in the world.

DC ring is set at neutral position (Fig. 1):
Background blur and foreground blur have the same
characteristics.

DC ring is set at R (rear) position (Fig. 2):
Spherical aberration occurs. In this case, light
rays from the background look beautifully soft and
blurry -- declining in intensity from the core of
the light source outward. On the other hand, light
rays from the foreground are blurred with ring-shaped
halos.

DC ring is set at F (front) position (Fig. 3):
Spherical aberration occurs in reverse direction
(R position). In this case, light rays from the
foreground look beautifully soft and blurry."
---

  Sounds very cool. There are some little
graphs showing the ray tracing but no actual
photos of what the effect looks like.

Greg