[kevinschoenmakers]

United States Patent: 7283311)

The present invention relates to a wide-angle zoom lens system which is suitable for a single-lens reflex (SLR) camera, and especially suitable for a digital single-lens reflex camera.
Suitable for a digital SLR camera having a smaller imaging device.
16.48-131.0 (3.5-5.8)

The real design focal range and aperture and marketing data are not the same.

I don't know any Pentax DA16.5-131/3.5-5.8 lenses.
Maybe I'm wrong, but there are several similiar patents for such lens.

But it mentions Tamron as the assignee...

[ogl]

But it mentions Tamron as the assignee...

Strange...Broken link. Because it's link of searching engine...I think.

It was Pentax zoom.

United States Patent 7,283,311
Saori October 16, 2007

Wide-angle zoom lens system

Abstract

A wide-angle zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group, in this order from the object. Upon zooming from the short focal length extremity to the long focal length extremity, a distance between the positive first lens group and the negative second lens group increases, a distance between the negative second lens group and the positive third lens group decreases, and a distance between the positive third lens group and the positive fourth lens group decreases. The wide-angle zoom lens system satisfies a number of conditions. Inventors: Saori; Masakazu (Saitama, JP)
Assignee: PENTAX Corporation (Tokyo, JP)
Appl. No.: 11/550,118
Filed: October 17, 2006

Foreign Application Priority Data
Oct 19, 2005 [JP] P2005-304966


Current U.S. Class: 359/687 ; 359/715; 359/740; 359/774
Current International Class: G02B 15/14 (20060101)
Field of Search: 359/687,715,740,774

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wide-angle zoom lens system which is suitable for a single-lens reflex (SLR) camera, and especially suitable for a digital single-lens reflex camera.

2. Description of the Prior Art

In a digital SLR camera, the size of the imaging device is smaller than a frame size of the film for a silver-halide SLR camera. Therefore an optical system having a wider angle-of-view (shorter focal length) is necessary.


TABLE 2 FNO. = 1: 3.5-4.9-5.8 f = 16.50-50.10-131.33

TABLE 3 FNO. = 1: 3.5-4.9-5.8 f = 16.49-50.03-131.11

TABLE 4 FNO. = 1: 3.5-4.9-5.8 f = 16.48-50.00-131.00

According to the above description, a wide-angle zoom lens system of a four-lens-group arrangement, i.e., negative, positive, negative and positive lens groups, in this order from the object, having the following features can be obtained:

(i) being suitable for a digital SLR camera having a smaller imaging device;

(ii) the angle-of-view of approximately 80.degree. at the short focal length extremity; and

(iii) a zoom ratio exceeding 8.




The images are only for money.

[thibs]

Why the heck didn't they market it

[ogl]

16.5-135 is not bad zoom. put WR and it could be HIT.

Tokina is just released in June, 2009.

Tokina has postponed this lens from 2007. IMO.

DA*11-16/2.8 SDM + DA16-135 WR...What do you think?

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Last edited by ogl; 12-08-2009 at 03:43 AM.