Q

What is the difference between a flat lens and conical lens?

A
The picture is the same regardless whether you select a flat pinhole lens or conical pinhole lens. The difference lies in the installation. Most people find it easier to install a conical lens in drywall or ceiling tile. The conical lens board requires less of a hole in the surface area of drywall or ceiling tile. By the same token, the flat lense is better when using it in something thin, such as a shirt or blouse. Both cameras only need a very small hole to see. The closer the pinhole lens is to the exterior surface of the material, the wider the field of view will be.
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