soczewka pierścieniowa

In 1857 the light was upgraded with a Fresnel lens.

The tower later became the first to use the revolutionary Fresnel lens, in the early 1820s.

There are many light houses, some with detailed Fresnel lenses.

The light was concentrated and focused with a system of Fresnel lenses.

In 1834, the light was equipped with a Fresnel lens.

The light was a first-order Fresnel lens which stood 134 feet above the water.

It was built and first lit in 1905 with a fifth order Fresnel lens.

To control the focus of the light, a Fresnel lens was used.

A last check showed the Fresnel lens was still green.

The tower used to be white with a red band and had a Fresnel lens.