crown lens

But girl, look how good you look in that flower crown lens!

������ Hall and Dollond did was to make the outer or crown lens of the objective as before, and place behind it a plano-concave lens of dense flint glass.

It will be seen that the flint glass component by itself is a concave lens and therefore neutralises in part, or in whole, the convex crown lens.

Fitted with a reversible crown lens for photography.

This had the effect of neutralizing the chromatic effect, or color aberration, while at the same time only part of the refractive effect of the crown lens was destroyed.