Canon Patent: RF 28-70mm F2.8 Lens

Canon patent application 2024104916 (Japan, published on August 6, 2024) discusses various optical formulas for a yet to be released RF lens: 28-70mm f2.8.

From the patent literature:

• Description of the Related Art: In recent years, imaging optical systems used in imaging devices have been required to have high optical performance, a high zoom ratio, and a small size.
• The zoom lens of Patent Document 1 has a lens group arranged in the order of positive, negative, positive, positive, negative, positive, from the object side to the image side. However, since the refractive power of the second lens group is strong, the chromatic aberration of magnification at the wide-angle end tends to become large, and the fluctuation of the curvature of field occurring during zooming tends to become large .
• SUMMARY OF THE PRESENT EMBODIMENTS: An object of the present invention is to provide a zoom lens which has high optical performance, a high zoom ratio and is compact.

Example 1

• Focal length: 28.80-67.90
• F-number: 2.88-2.92
• Half angle of view: 34.93-17.67
• Image height: 21.64
• Total length: 132.38-158.83
• Back Focus: 15.39-34.87

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