Designed by Harting and influenced by the Cooke Triplet, the Heliar was placed on the market in 1902. The original patent (1900) shows a symmetrical arrangement with the rear group matching the front group, the second patent shows an alteration to the rear group with the positive element becoming bi-convex. Shortly after this Harting introduced another lens, the Dynar, where the elements in the outside groups were switched i.e. the positive element was on the outside. Later Heliar lenses were made to the design of the Dynar (an advertisement for the Heliar in the 1927 BJA shows the Dynar configuration). An f3.5 series was introduced after World War I.