OPTICAL IMAGING SYSTEMS, IMAGING UNITS AND ELECTRONIC EQUIPMENT

Abstract

The photographic optical system comprises four lens elements in order from the object side to the image side along the optical path: the first lens element, the second lens element, the third lens element, and the fourth lens element. The first lens element has negative refractive power and its image-side surface is concave in its anti-axial region. The second lens element has positive refractive power. The third lens element has positive refractive power and its object-side surface is concave in its anti-axial region and its image-side surface is convex in its anti-axial region. The photographic optical system also includes an aperture diaphragm placed between the second and third lens elements. The invention also reveals a photographic apparatus comprising a photographic optical system and an electronic apparatus comprising a photographic apparatus.

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