Solinar
Analog Preferred
Murray - not quite right. The Heliar predates the first World War and is one of the designs which followed the original Cooke triplet.
The original Cooke triplet was 3 glass elements in 3 groups.
The Tessar design - which includes the Skopar and Xenar - adds a cemented doublet of two different types of glass to the third group to yield 4 elements in 3 groups.
The Heliar uses a cemented front doublet in addition to the rear doublet of the Tessar to yield a design that has 5 elements in 3 groups.
Back before anti-reflective lens coatings were common - a triplet design reduced the number of interior glass to air surfaces.
The original Cooke triplet was 3 glass elements in 3 groups.
The Tessar design - which includes the Skopar and Xenar - adds a cemented doublet of two different types of glass to the third group to yield 4 elements in 3 groups.
The Heliar uses a cemented front doublet in addition to the rear doublet of the Tessar to yield a design that has 5 elements in 3 groups.
Back before anti-reflective lens coatings were common - a triplet design reduced the number of interior glass to air surfaces.
