Moving up one step from there, a camera with a single element lens has a convex lens. It may be a meniscus lens which is convex on one side and concave on the other, but it is thicker in the middle than the edges and functions like a convex lens. (The meniscus shape helps the lens focus light on a flat focal plane.)

Friend,convex lens is used in phone camera.F first time.,it was my mistake

In our phone camera, which lens is used: concave or convex lens?

In a phone camera, both concave and convex lenses are used. The specific type of lens used depends on the purpose it serves within the camera system. Let's explore the different lenses and their functions in detail.

Convex Lens:
Convex lenses are thicker in the middle and thinner at the edges. They are also known as converging lenses as they converge or focus the incoming light rays. Convex lenses are primarily used in phone cameras for the following purposes:

1. Focusing: Convex lenses help in focusing the light rays onto the image sensor, allowing for sharp and clear images to be captured.
2. Zooming: In some phone cameras, zooming capabilities are achieved by using multiple convex lenses placed in a configuration that allows for variable focal lengths. This enables users to zoom in or out on a scene without physically moving closer or farther away.

Concave Lens:
Concave lenses, on the other hand, are thinner in the middle and thicker at the edges. They are also known as diverging lenses as they cause light rays to spread out or diverge. Concave lenses are used in phone cameras for specific purposes:

1. Wide-angle Photography: Concave lenses have a wider field of view and can capture more of the scene within the frame. This makes them ideal for wide-angle photography, where a larger area needs to be covered.
2. Correcting Aberrations: Phone cameras often use a combination of convex and concave lenses to correct various aberrations like distortion, chromatic aberration, and spherical aberration. The concave lens helps to counterbalance the optical imperfections caused by the other lenses in the system.

Composition of Phone Camera Lens:
The lenses used in phone cameras are not made of plain glass but rather multi-element lens systems that include both convex and concave lenses. These lenses are typically made using high-quality materials, such as specialized glass or plastics, to ensure optimal image quality.

Conclusion:
In summary, phone cameras use a combination of convex and concave lenses to achieve different functionalities. Convex lenses are used for focusing, zooming, and capturing sharp images, while concave lenses are used for wide-angle photography and correcting optical aberrations. The composition of these lenses involves the use of specialized materials to ensure optimal image quality for phone camera users.