The Lomography Petzval 58 Bokeh Control Art Lens

In article , android wrote:

Sandman:
I'm a backer, love the "normal" Petzval lens and this
sounds really interesting!

android:
Bokeh control = fussy focus?

Sandman:
More like more control over the things not in focus.
It's probably a lot like the "Defocus Control" lenses from
Nikon

android:
Soo... You move an element or two around to create extra
spherical aberration, or something... That would translate as
fussy focus control to me.

Sandman:
I read "fussy focus" to mean that it can't focus sharply in the
focus plane. The "Bokeh control" affects only the out of focus
parts.

I also found this on nikonusa.com re that 135mm of yours: "Control
the degree of spherical aberration in background or foreground
elements for more creative control." http://tinyurl.com/q2jh7up

Yup

--
Sandman

In article ,
Sandman wrote:

In article , android wrote:

---
Since your into bokeh at the deep end: What's your opinion on soft
focus filters?

It certainly has its place. Not that it has anything to do with bokeh though.

Sure it does... Some like the Zeiss Softars have a coating of micro
lenses giving the image a softer appearance without losing focus...

http://tinyurl.com/nqj4sl5

https://en.wikipedia.org/wiki/File:V...uerkirsche.jpg
--
teleportation kills

In article ,
Sandman wrote:

In article , android wrote:

Sandman:
I'm a backer, love the "normal" Petzval lens and this
sounds really interesting!

android:
Bokeh control = fussy focus?

Sandman:
More like more control over the things not in focus.
It's probably a lot like the "Defocus Control" lenses from
Nikon

android:
Soo... You move an element or two around to create extra
spherical aberration, or something... That would translate as
fussy focus control to me.

Sandman:
I read "fussy focus" to mean that it can't focus sharply in the
focus plane. The "Bokeh control" affects only the out of focus
parts.

That's not entirely correct. Read the link you snippet and you'll see
that SA surely affects the focus plane. Here you go:

https://en.wikipedia.org/wiki/Spherical_aberration

I also found this on nikonusa.com re that 135mm of yours: "Control
the degree of spherical aberration in background or foreground
elements for more creative control." http://tinyurl.com/q2jh7up

Yup

It confirms that that I wrote...
--
teleportation kills

In article ,
RichA wrote:

On Tuesday, 2 June 2015 02:00:35 UTC-4, Sandman wrote:
In article , android wrote:

I'm a backer, love the "normal" Petzval lens and this sounds
really interesting!

android:
Bokeh control = fussy focus?

Sandman:
More like more control over the things not in focus. It's probably
a lot like the "Defocus Control" lenses from Nikon

Soo... You move an element or two around to create extra spherical
aberration, or something... That would translate as fussy focus
control to me.

I read "fussy focus" to mean that it can't focus sharply in the focus
plane. The
"Bokeh control" affects only the out of focus parts.

The Petzval lens employs an optical aberration that is called the "Petzval
field
curvature", which is slightly different. The Petzval lens is corrected for
spherical aberrations, but introduces a field curvature instead, as well as
vignetting.

--
Sandman

You know, the astronomical community has devices that will fix that.
2-element refractive telescopes, Schmidt-Cassegrain telescopes not specially
corrected also have curve fields.

And there is Photoshop!
--
teleportation kills

In article , RichA wrote:

Sandman:
I'm a backer, love the "normal" Petzval lens and this
sounds really interesting!

android:
Bokeh control = fussy focus?

Sandman:
More like more control over the things not in focus.
It's probably a lot like the "Defocus Control" lenses from
Nikon

android:
Soo... You move an element or two around to create extra
spherical aberration, or something... That would translate as
fussy focus control to me.

Sandman:
I read "fussy focus" to mean that it can't focus sharply in the
focus plane. The "Bokeh control" affects only the out of focus
parts. The Petzval lens employs an optical aberration that is
called the "Petzval field curvature", which is slightly
different. The Petzval lens is corrected for spherical
aberrations, but introduces a field curvature instead, as well as
vignetting.

You know, the astronomical community has devices that will fix that.
2-element refractive telescopes, Schmidt-Cassegrain telescopes not
specially corrected also have curve fields.

So, yeah, the aberrations in the Petzval lens is there by choice.

--
Sandman