[RuiC]

The height of the image created is only 21mm whereas FF supposed to be a little less then 24mm.

So, i won't be happy too fast.

21mm height just means "vignetting"

[Kunzite]

Didn't we already established that "image height" is not the frame/sensor's height, and that full frame lenses like the Canon 600mm have the same 21.64mm "image height"?
If not, can we do it now?

[RuiC]

Didn't we already established that "image height" is not the frame/sensor's height, and that full frame lenses like the Canon 600mm have the same 21.64mm "image height"?
If not, can we do it now?

Did we???

[Mistral75]

Did we???

Yes, a few times .

Y = 21.64mm is the radius of the image circle.

---

Last edited by Mistral75; 10-05-2012 at 10:00 AM.

[Kunzite]

We just did it. Again.
Canon 600mm F4 ????????????????????????????????So-net???
像高 (image height) 21.64mm

[Mistral75]

You can read it in english here, filed by Pentax-Ricoh :

United States Patent Application: 0120229689

Good catch. This patent is first and foremost the one of Q's 06 Telephoto Zoom 15-45mm f/2.8.

See the TIFF version of the patent that includes tables and figures:

Publication Images

Out of six illustrations of the patent, five are for a 15.45-43.65mm f/2.9 with a 4.65mm image circle's radius (see Tables 2, 5, 8, 11 and 17) and one is for a 70.21-198.32mm f/2.9 with a 21.64mm image circle's radius (see table 14).

[ogl]

Did I miss it? Already discussed?

This patent is for lens with stabilization.

since part of the fourth lens group is used as an image-blur correction lens group (image-stabilizing lens group) that is moved in a direction orthogonal to the optical axis, the number of lens elements thereof is large, complicating the configuration and increasing costs.

[RuiC]

Good catch. This patent is first and foremost the one of Q's 06 Telephoto Zoom 15-45mm f/2.8.

See the TIFF version of the patent that includes tables and figures:

Publication Images

Out of six illustrations of the patent, five are for a 15.45-43.65mm f/2.9 with a 4.65mm image circle's radius (see Tables 2, 5, 8, 11 and 17) and one is for a 70.21-198.32mm f/2.9 with a 21.64mm image circle's radius (see table 14).

Yes the 70-200 is referred in " Numerical Embodiment 5
"

[ogl]

United States Patent: 8223437

fresh patent - July, 17 2012


Zoom Ratio = 1.25 - rather strange zoom 16-20 f/4 IMO
According to the present invention, a wide-angle zoom lens system with the following features can be attained:

a miniaturized zoom lens system is attained;

the correcting of aberrations, such as distortion and astigmatism, can be done over the entire zooming range;

aberration fluctuations upon focusing can be reduced by introducing an internal focusing lens arrangement in which the positive second lens group is provided as the focusing lens group; and a short minimum photographing distance is attained.





United States Patent: 7324293


found also 20-38/3.3 zoom...


a high quality retrofocus wide-angle lens system with the following features can be attained:

(i) being thin (miniaturized) in the optical axis direction; (PANCAKE???)

(ii) coma, distortion and chromatic aberration are suitably corrected; and

(iii) achieving an angle-of-view of approximately 70.degree..

Is it new DA LIMITED???

[DSims]

You can read it in english here, filed by Pentax-Ricoh :

United States Patent Application: 0120229689

Thanks.

From the last lines of the application:

"[0116] Obvious changes may be made in the specific embodiments of the present invention described herein, such modifications being within the spirit and scope of the invention claimed. It is indicated that all matter contained herein is illustrative and does not limit the scope of the present invention. "


I'm not a patent lawyer, but I presume that Pentax could modify the design to cover the complete FF+SR image circle. Obviously they'll make the image circle large enough to work with whatever sensor size they're using on the new large-sensor K-mount camera they're designing right now. (It'll have to be larger than the current 1.5x crop cameras - doing otherwise would go against everything they've been telling us for the last 10 months).

[Quicksand]

Did I miss it? Already discussed?

This patent is for lens with stabilization.

since part of the fourth lens group is used as an image-blur correction lens group (image-stabilizing lens group) that is moved in a direction orthogonal to the optical axis, the number of lens elements thereof is large, complicating the configuration and increasing costs.

That's from a section of the patent application that describes the prior art -- i.e., older technology that this lens improves upon.

That's why it talks about "complicating the configuration and increasing costs." Those are disadvantages of other referenced lenses that are avoided by the lens described in the patent application.

[RuiC]

....



United States Patent: 7324293


found also 20-38/3.3 zoom...


a high quality retrofocus wide-angle lens system with the following features can be attained:

(i) being thin (miniaturized) in the optical axis direction; (PANCAKE???)

(ii) coma, distortion and chromatic aberration are suitably corrected; and

(iii) achieving an angle-of-view of approximately 70.degree..

Is it new DA LIMITED???

This one is not a zoom but a fixed 20mm instead !

[starbase218]

It's nice to see evidence of Pentax R&D activities. That's all this is really, nothing more.

[RonHendriks1966]

found also 20-38/3.3 zoom...


a high quality retrofocus wide-angle lens system with the following features can be attained:

(i) being thin (miniaturized) in the optical axis direction; (PANCAKE???)

(ii) coma, distortion and chromatic aberration are suitably corrected; and

(iii) achieving an angle-of-view of approximately 70.degree..

Is it new DA LIMITED???

I would like to have this zoom! If it is a metal DA zoom Ltd.

[Blue]

I would like to have this zoom! If it is a metal DA zoom Ltd.

There is a DA LTD zoom on the road map that approximates that focal range.