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12-08-2009, 01:44 AM   #61
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QuoteOriginally posted by ogl Quote
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...

12-08-2009, 02:31 AM   #62
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QuoteOriginally posted by kevinschoenmakers Quote
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.

Last edited by ogl; 12-08-2009 at 02:47 AM.
12-08-2009, 03:11 AM   #63
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Why the heck didn't they market it
12-08-2009, 03:34 AM   #64
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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?


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