ocean2059 wrote:
This is going to be a very interesting lens offered by Voigtlander for sure. The optical design of this lens is a modified Tessa design. The traditional Tessar designs are three lens groups with four/five-element configurations. Both Voigtlander’s classic Heliar 50/3.5 and limited collapsible 50/2 are both five-element in three groups design (2-1-2), where Leica Elmar-M 50/2.8 is four-element in three groups (1-1-2), as does the Hasselblad/Zeiss CB 160/4.8 lens. Both the Leica and Hasselblad/Zeiss lenses have a larger front element whereas Voigtlander uses two elements in the front group design. The main advantage of traditional Tessar design is that it uses few elements to gather the light and as a result some of images have very natural and organic feel, particularly in relatively good lighting conditions, such as for late afternoon golden light. The disadvantage is that the f-stop of this type of design is pretty large since there are not a lot of glass elements to correct the light pass. The limited edition of the collapsible Voigtlander classic Heliar 50/2 was pushing the Tessar design limit a bit. But in this new lens, Voigtlander is adding an element in the middle group to a six-element three groups design (2-2-2). Hopefully this modified design will achieve good performance at f/1.5 and to improve/enlarge sharper center image circle, yet to retain the traditional smooth and natural look of the traditional Tessar characteristics.
The six element Heliar is then a Tessar, which has been modified to accomodate a greater lens speed of f/1.5 instead of f/2.8 in common Tessar types. (Contax/Yashica 45/2.8 Tessar, Leica 50/2.8 Elmar, Nikon 45/2.8P)
Aug 17, 2021 at 06:14 PM
Previous versions of bjornthun's message #15682906 « Official: Voigtlander Heliar Classic 50mm F1.5 VM »
