Maybe it is not realized that the way a magnifying lens works is based on the different refractive index of the lens versus the medium in which it is submerged. The refractive index of air is about 1.0; of water is about 1.3; of glass is about 1.6; and of plastic about 1.5. So a glass lens in air is very effective; but a plastic lens in water is the worst...hardly any magnification at all compared to being in air.
Use a glass magnifying lens unde waer, or better yet, use a compound lens with an air pocket sandwiched between two glass lenses.
Use a glass magnifying lens unde waer, or better yet, use a compound lens with an air pocket sandwiched between two glass lenses.
