Leo G writes:
The Zeiss Biogon 35mm and a bunch of the rest are backordered.
But I found a Zeiss Distagon ZM 35mm f2 for Nikon -- what is the difference in Biogon and Distagon? I can't get a clean definition from Google. Would the same review apply?
DIGLLOYD: Biogon and Distagon are different types of Zeiss lens designs. Zeiss names their lenses by optical design; Leica names their lenses mainly by lens speed (Summilux, Summicron, Elmarit, Elmar), with some design qualifiers (“Super”,“ASPH”). Nikon uses “ED” and “VR”, and Canon uses “L” and “IS” (not nearly as sexy).
The 35mm f/2 Biogon is a rangefinder lens for the Leica M9 or Zeiss Ikon rangefinder cameras or ALLVIEW cameras like the Sony NEX-7. Great demand is being driven by the Leica M9 and various ALLVIEW cameras.
The Biogon design is not suitable for a DSLR due to mirror clearance issues; Biogon lenses have a short back-focal distance, so short that ray angle is often an issue, resulting in color shading. A 35mm f/2 Biogon for a DSLR does not exist.
The Zeiss 35mm f/2 Distagon is a DSLR lens for Canon or Nikon or Pentax; the Distagon design has ample back-focal distance for clearing a DSLR mirror, as well a design that covers the mirror/focusing screen properly.
A Biogon is always smaller and lighter than an equivalent Distagon, given the same focal length and f-stop, because it can be designed without regard for a DSLR mirror.